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May 11

before penicillin

Penicillin was not widely used before the 1940s but what did they use before then to treat illnesses such as inner ear infections strep throat and pneumonia? — Preceding unsigned comment added by Wrk678 (talk • contribs) 00:42, 11 May 2012 (UTC)

See Antibacterial#History, antibiotics are not as necessary to treat infectinos as much as we have come to rely upon them. For an ear infection for example, avoiding dairy/sugary products and keeping the ear dry can help while your body fights off the infection itself. Unique Ubiquitous (talk) 01:06, 11 May 2012 (UTC)

Basically these are infections which would have killed many people who acquired them: if the initial infection didn't see you off, then a secondary infection or complication may have. They still have the potential to kill people without good immune systems, such as elderly, children or people on immunosuppressant drugs. --TammyMoet (talk) 09:16, 11 May 2012 (UTC)

Well, that Polygonum I mentioned a few days back was also used for ear infections by Dioscorides [1] (see Panicudine, which I started then) - also Stipa of some sort, Psyllium; also an elxine, Parietaria or Helxine of which this translation's author seems uncertain of the identity, but which sounds like some seriously good stuff. I mean, remember, Dioscorides didn't know that purulent ears, inflamed tonsils, erysipelas (cellulitis), chronic cough, and "all types of inflammation" would be treated by antibiotic - yet he ascribes all those activities to this plant, and not to a different larger form of "helxine" for which he has a separate entry. I'm pretty convinced the ancients knew their stuff, even if they did occasionally add in some white lead in hair-raising concotions. We could learn a lot from them. N.B. there is absolutely zero information about antibacterial properties of the plants suggested as elxine in PubMed, despite that remarkable paragraph by Dioscorides. Wnt (talk) 12:06, 11 May 2012 (UTC) Note: Nicholas Culpeper, writing on Pellitory of the Wall, gives a description more like a painkiller. [2] Nonetheless, I'm not at all sure this is what Dioscorides was writing about. Wnt (talk) 14:42, 11 May 2012 (UTC)

I'm also surprised that the antibacterial properties of Honey aren't separately mentioned in the article quoted by Unique above. They've been well known about for some time, before being rediscovered by medicine in the last few decades. --TammyMoet (talk) 13:51, 11 May 2012 (UTC)

Inner ear infection is mostly caused by a virus, so no real treatment exists; Pneumonia was a killer disease before antibiotics; can't find a lot on treatments for these, it's as if before the 20th century everyone was busy trying to cure syphillis. Toxic metal compounds were used a lot, arsenic in the form of Fowler's solution, arsphenamine, or arsenic trioxide; thallium salts, various forms of mercury, like mercury(II) chloride. See also medical uses of silver. Ssscienccce (talk) 14:15, 11 May 2012 (UTC)

Actually, it is not impossible that an herb could be an immune modulator after the fashion of imiquimod; the right modulator might persuade the body to put on a different and possibly more useful immune response toward an infection. Wnt (talk) 14:42, 11 May 2012 (UTC)

The short answer is that prior to the development of antibiotics, a lot of people who developed serious bacterial infections died because there just weren't any effective alternatives. My grandmother's sister died in her late teens from an infection caused by a troublesome wisdom tooth. Without proper antibiotics, you're left with plain old supportive care: keeping the patient comfortable, supplying IV fluids as needed, and hoping for a good outcome. TenOfAllTrades(talk) 14:28, 11 May 2012 (UTC)

My doctor always told me that without antibiotics a inner ear infection will cause the eardrum to burst, not to mention the fact that an inner ear infection is extremely painful. Although some ear aches are caused by viruses most ear infections that last more than a day or two are caused by bacteria. — Preceding unsigned comment added by Wrk678 (talk • contribs) 01:41, 12 May 2012 (UTC)

Not sure if it was used for the three specific infections mentioned by the OP, but Sulfonamide (medicine) was used before penicillin. The Prontosil form of sulfa was introduced in 1935., and was effective against streptococci. Actual sulfa was an old drug (1906) and out of patent. It was very helpful in WW2and the article says it saved tens of thousands of wounded soldiers from death. Before sulfa came into use there was [[Arsphenamine}Salvarsan]], used starting around 1910 to treat syphilis. Before these, physicians used a variety of chemotherapeutic agents with limited success, such as carbolic acid, alcohol, iodine, and iodoform in the peritoneal cavity or elsewhere. These agents might kill pathogens, but tissue damage was also likely. Quinine was effectively used to treat malaria. A typical recommendation from 1904 was to treat infections by "absolute rest of both the patient and the part involved, drainage and evacuation of septic foci, soothing and cleansing applications to the parts, promotion of elimination and support of the patient." This is not so different from what a homeopathic doctor would have done at the time, except the "regular" or allopathic physician might open, irrigate and drain] the infected area. Not sure what the doctor of the pre-antibiotic era would do to treat an inner ear or throat infection, but a mastoid infection would be surgically drained, and antiseptics might be instilled in infected areas such as sinuses or the abdomen or genitals. By [3], war surgeons found it effective to use diluted bleach with other chemicals (Dakin's solution) to treat wound infections. Back in the 19th century, a physician would have likely treated an infection by administering a highly poisonous mercury compound called Calomel, by purging the patient with laxatives, and by bleeding the patient, which were rarely beneficial and all of generally increased mortality and had severe side effects. But even back in the US Civil War, some surgeons treated abdominal infections by irrigating with boiled (and cooled) water, before they had a clear germ theory of disease. Edison (talk) 04:17, 12 May 2012 (UTC)

For a project with strict rules against giving medical advice, I reckon this thread is dangerously packed with misinformation and quackery. We really shouldn't be describing non-professional "cures" here. HiLo48 (talk) 04:35, 12 May 2012 (UTC)

Do you have a beef with referenced historical information which answers the OP's question about how infections were treated before penicillin? Any accurate answer to a question about how things were done in an earlier era will describe ways which are no longer considered optimal, whether it is farming, fighting a war or fighting infection. Edison (talk) 04:39, 12 May 2012 (UTC)

Not at all, but a lot of the "advice" above is not "referenced historical information". HiLo48 (talk) 04:45, 12 May 2012 (UTC)

If you see misinformation above, or advice, by all means, point it out. Wnt (talk) 21:12, 12 May 2012 (UTC)

I see some ill-founded intuitive suggestions, based on original research, by guess, and by gosh, as well as my response which is based on a search of books from the pre-penicillin 20th century. Before penicillin there was sulfa, before that there was supportive therapy, giving the body a chance to heal itself and the immune system a chance to defeat the infection, along with operations to drain abcesses, boils, and other foci of infection, and the questionable use of chemical antiseptics which killed pathogens but also harmed body tissues, This is distinct from earlier medical quackery with calomel, bleeding and purging. Edison (talk) 03:40, 13 May 2012 (UTC)

I didn't see any misinformation there - there was no claim that was a good idea, just what the "doctors" did. It is of course true that many Western practices up even to the 1800s were frightfully backward by comparison with the standard of care one would expect in ancient Rome or medieval Islam. Wnt (talk) 18:11, 14 May 2012 (UTC)

Minimizing the effects of aging on skin

How a person can minimize the effects of aging on skin? Is life extension technologies or hormone replacement therapies developed enough to make someone look younger at their old age? What is the possibility of research progress in the next 30 years? Should Resveratrol supplement from a much younger age help someone to prevent aging-related changes in skin? What measures should be taken by someone who is 19 years old to delay aging? --NGC 2736 (talk) 03:58, 11 May 2012 (UTC)

While there is not a great deal of publicly available good scientific research on the subject of preventing skin ageing, beauty therapists are trained to advise on this. I'll give you some advice here, which any beauty therapist would be able to give you: drink plenty of water, use a good moisturiser day and night, cleanse your skin thoroughly before you go to bed and when you wake up, eat a balanced diet, don't smoke - and choose your grandparents well. Whether you should supplement with anything is medical advice which we can't give here. --TammyMoet (talk) 09:10, 11 May 2012 (UTC)

And don't, under any circumstances, lie around half-naked in the sun! FiggyBee (talk) 09:28, 11 May 2012 (UTC)

Calorie restriction, avoid over-cooked food, alcohol, fermented meat & donuts. Eat lots of salad and fruit. SkyMachine ⁽⁺⁺⁾ 09:52, 11 May 2012 (UTC)

What is the most accepted theory of aging? --NGC 2736 (talk) 10:17, 11 May 2012 (UTC)

See senescence for the general theory. As for skin, of those listed above, avoiding UV exposure is, by far, the most important. This can be done be staying inside, covering up when outside, using sunblock, etc. And absolutely never use a tanning bed. StuRat (talk) 15:03, 11 May 2012 (UTC)

See Photoaging for the specific theory relating UV-light and aging. OsmanRF34 (talk) 21:43, 12 May 2012 (UTC)

I think it goes well beyond theory at this point, it's an established fact. StuRat (talk) 22:18, 12 May 2012 (UTC)

It is a theory. But the proper meaning of 'theory' is not 'hypothesis', it is 'an explanation backed by facts.' Anyway,, I don't think there are any doubts in the connexion between UV rays and skin aging. ~~ — Preceding unsigned comment added by OsmanRF34 (talk • contribs) 11:59, 13 May 2012 (UTC)

Is Element Zero In Mass Effect Possible

In the Mass Effect series theres an element that effects the mass around it when charged with electricity. Its usually found near pulsars and neutron stars. Would this kinda thing be possible cause you can control gravity with this stuff. — Preceding unsigned comment added by Lightylight (talk • contribs) 04:23, 11 May 2012 (UTC)

Whether the stuff can control gravity or not doesn't matter. In either case, the stuff isn't possible. Plasmic Physics (talk) 08:21, 11 May 2012 (UTC)

See antigravity. The ideas are just as speculative but you'll get more respect from the crowd if you describe them in those terms. Wnt (talk) 11:45, 11 May 2012 (UTC)

Atoms are made of electrons, protons and neutrons. Elements are numbered according to the number of protons (which is the same as the number of electrons) that they have. An "element zero" would presumably have none of either - so it could only consist of neutrons. We actually have an article about this: Neutronium. An "atom" consisting of just one neutron would not generally be described as an "atom" - so we don't normally place it on the periodic table at number zero - but we could - and several people have actually done that. Sadly, a neutron left on it's own decays with a half-life of around 15 minutes - so there wouldn't be much of this stuff around for very long unless something was continuously replenishing it. You can also have groups of more than one neutron (which, technically, would be isotopes of neutronium) - and groups of two neutrons (Dineutron) have definitely been observed in nature. Tetraneutron (a group of four neutrons) is hypothesized to be possible - and there is some evidence that it actually exists, although this is controversial.

However, I doubt we'll find that we can control gravity or do anything else particularly exotic with neutronium. Sometimes science fiction is just fiction. 216.136.51.242 (talk) 15:07, 11 May 2012 (UTC)

Now that we're talking about actual neutronium, what is its theorised state in a neutron star - liquid or solid, or super-solid? Can it even exist in the liquid phase, or does it sublime under all conditions? Plasmic Physics (talk) 06:29, 12 May 2012 (UTC)

I should note that "Element Zero" is the nickname, not its place in the periodic table. That said I don't see a potential way any chemical, elemental or compound, could change its mass when subjected to an electric field. Mass is a function of gravity attraction, which, according to the most commonly accepted theory, is a function of the curvature of spacetime caused by an object "resting" on it (in a fashion somewhat similar to a giant rubber sheet). This is a massively gross oversimplification but it explains the problem well. The conservation of matter states that you cannot create matter, which is the only thing that has mass, or destroy it. For an "element zero" to be possible it would have to destroy in a reversible way mass when a current was applied so that its "dent" in the sheet would become greater or lesser. In general it would require the relativity model of gravity to be wrong and Gravitons to exist, and somehow the element to generate a field that interacts with gravitons. The theories that posit Gravitons have serious problems (as the article points out). And beyond that, even if Graviton theories were true it is probably not possible to interact with gravitons in a meaningful way because they would be massless particles that have a very low probability of any sort of interaction with other forces. HominidMachinae (talk) 19:26, 12 May 2012 (UTC)

is the file autorun.inf executable by itself?

I have an autorun.inf file in my USB and it looks like some kind of messy code in notepad, but I cannot find any other application linked to this file. I wonder if it is some kind of malware that is executable by itself?--Noname67097 (talk) 05:24, 11 May 2012 (UTC)

autorun.inf is a file checked for by Windows when you insert a CD or other volume device, and contains instructions about what to do when that volume is inserted into the computer. It is not an executable in itself, but can cause Windows to launch some other executable. FiggyBee (talk) 05:43, 11 May 2012 (UTC)

Thinking out loud, what if you rename a *.exe file to autorun.inf. Will windows execute the code? Zzubnik (talk) 11:24, 11 May 2012 (UTC)

Well, the article says it's a text file, so no sane computer should try to run it. Then again, this being Windows, who knows? Wnt (talk) 11:43, 11 May 2012 (UTC)

For the future, note you're probably better off with questions like this at the Computing Reference Desk. -RunningOnBrains^(talk) 19:41, 12 May 2012 (UTC)

What's the term for one way only traffic lane design?

Hi,

I remember years ago reading about a traffic plan system that avoided making intersections, and used only one way roads that fed into each other using over passes and under passes kind of thing. I'm trying to find the term that describes this type of roadway.

It would be like the artery / vein system in the body, where the blood flow is practically one way only.

Thanks

--InverseSubstance (talk) 06:49, 11 May 2012 (UTC)

Controlled-access highway?--Shantavira|^{feed me} 07:21, 11 May 2012 (UTC)

Sounds impractical. In addition to the high cost of all those bridges, you'd need a cloverleaf interchange to replace every intersection. Those use up a huge amount of land, concrete, and money. StuRat (talk) 14:54, 11 May 2012 (UTC)

Well it's the way every motorway junction is designed in the UK! TammyMoet (talk) 20:34, 11 May 2012 (UTC)

Not Junction 3 on the M50! Tevildo (talk) 11:25, 12 May 2012 (UTC)

You need to help me with what a "motorway" is in the UK. Obviously, not every road or driveway intersection has a cloverleaf, so are you talking about controlled-access highways only ? If so, that's the same as in the US. StuRat (talk) 02:32, 12 May 2012 (UTC)

It's not hard to imagine a system of streets that has forks but no crossings. I've seen plenty of districts, typically in city centres, in which all streets are one-way. It's somewhat harder to imagine combining these two features. But intersections and overpasses can both be avoided with roundabouts. —Tamfang (talk) 06:45, 12 May 2012 (UTC)

Roundabouts don't avoid intersections, they are just another type, with the same problems of having to be extra careful, slow down, and even stop in heavy traffic, with the risk of being T-boned. This can all be avoided with a well-designed cloverleaf. StuRat (talk) 16:00, 12 May 2012 (UTC)

But what do you do if you live in a Cul-de-sac? SkyMachine ⁽⁺⁺⁾ 08:28, 12 May 2012 (UTC)

Of course we have articles on everything: Motorway. This is what a typical motorway junction looks like from the air. This is what a typical motorway junction looks like if you're travelling down it. Note that if you want to leave the motorway you do so from the left-hand lane. --TammyMoet (talk) 09:13, 12 May 2012 (UTC)

If you're restricting the plans to one-way streets, you only need two slip-ramps (for going from road A to road B and for going from road B to road A, with A and B themselves continuing in their straight directions crossing over/under each other), not the usual of the usual set of eight ramps of a full cloverleaf (between A and B with two directions of travel on each, there are 8 permutations of directional connections between A and B). An alternative is to have A and B merge to form a single one-direction road for some distance and then diverge again. That seems to require more (or at least more specifically shaped) land. But it also might make more driver annoyance overall (*everyone* merges) unless there are lots of outside-edge lanes that do not require merging. Depending on whether A and B diverge from the same side (set of lanes) from which they merged or opposite, there could be an easier flow for drivers switching to "the other" road than for those keeping on "the same" one from which they came (and more weaving for the other set of drivers). A normal ramp configuration is easy to be unimpeded for drivers remaining on the same road but substantial deceleration and then acceleration and merging for those switching from one to the other. DMacks (talk) 18:54, 12 May 2012 (UTC)

With a properly constructed ramp, you don't have to slow down at all, and there's plenty of time to merge, or sometimes no need to merge, if the ramp becomes a new lane (which then becomes the exit ramp at the next cloverleaf). It's only when they try to skimp that you get tight turns without a slope, requiring you to brake. StuRat (talk) 23:59, 12 May 2012 (UTC)

WTC

This may have been answered before, but here are a few questions about the collapse:

1. Why did they collapse at such a high rate, if it was supposedly by a progressive process?
2. Why were contents of the office floors completely pulverised as if by explosive force? As noted by a firefighter, the largest recognisable component of any of the many desk phones that are bound to found at the site, was half a key pad. He also noted that the debris of the structure itself was basically turned to dust, instead of the rubble he usualy finds at a scene of a collapsed building.
3. What was the cause of the explosions in the vicinity of the 8 floor?
4. Allow me to speculate, is it possible for the towers to have been constructed with built-in demolision explosives?

Plasmic Physics (talk) 12:19, 11 May 2012 (UTC)

Probably:

1. Gravity & height. Things tend to get faster the further they have to fall.
2. What do you expect things to look like when crushed under tonnes of concrete which has fallen from hundreds of feet? How many collapsed tallest ever tower blocks has the fire fighter experience of?
3. Pass
4. Possible, yes. Most extremely unlikely. --Tagishsimon (talk) 12:37, 11 May 2012 (UTC)

You can find discussions of all that and more! starting with our 9/11 conspiracy theories article. --LarryMac | Talk 12:45, 11 May 2012 (UTC)

Plasmic, you seem like a clever person - how can you be at all attracted to ideas that a second cause is needed after someone flies a jet airliner into a building? I fairly strongly believe that the "9/11 conspiracy theories" are deliberate disinformation, disseminated to push the national discussion away from more realistic conspiracy theories, such as that the Bush administration or intelligence establishment or private companies or somebody paid bin Laden to fly those planes into the towers in order to justify creating a security state with massive spending on unproductive programs. In this way it would resemble the second-shooter theories of the Kennedy assassination, which divert discussion away from whether the Russians or American intelligence arranged with Oswald for the crime. Wnt (talk) 14:34, 11 May 2012 (UTC)

A conspiracy to create a conspiracy theory - would that be a meta-conspiracy ? Gandalf61 (talk) 14:38, 11 May 2012 (UTC)

That's a bit silly. Presumably the reason behind that conspiracy theory would be to make money for Halliburton, etc. However, considering that Bush and Cheney were already rich and powerful, it seems absurd to risk losing everything, and gamble on life imprisonment and humiliation, in order to increase their wealth a bit more. StuRat (talk) 14:44, 11 May 2012 (UTC)

Who said anything about imprisonment? Remember Arms-for-no-hostages? Remember Pat Robertson's support for Charles Taylor (Liberian politician)? This is the kind of stuff these people do, and even if they're caught they get away with it; it's not even an embarrassment except in the sense that they couldn't keep their unmentionables unmentioned. They'd muddy the waters a little, make it unclear whether they were paying to cause the attack or prevent it, the press would call it a scandal for a day or two, and people would move on. Wnt (talk) 16:20, 11 May 2012 (UTC)

You fail to understand the difference between killing foreigners and Americans. Politicians can get away with the former, but not with killing 3000 Americans, especially the rich ones working in the WTC. StuRat (talk) 16:24, 11 May 2012 (UTC)

Bear in mind we're talking about over $1 trillion dollars in spending generated by the attacks. That's a lot of money even for the richest people on the planet. So far as I know, there are no trillionaires ... yet. Wnt (talk) 16:32, 11 May 2012 (UTC)

But very little of that went to the decision makers in your conspiracy theory (Bush and Cheney). And the difference between being a powerful millionaire and imprisoned is a lot more than the diff between being a powerful millionaire and a slightly richer one. StuRat (talk) 16:37, 11 May 2012 (UTC)

If Dubya made any decisions for himself I'd be amazed. Wnt (talk) 16:55, 11 May 2012 (UTC)

I'm not a conspiracy theorist, but if you are interested where that money went — and a lot of it did go to people in the intelligence agencies — Dana Priest and William Arkin's Top Secret America book is pretty fascinating. George Tenet, for example, has made quite a tidy amount of money for himself as a "intelligence consultant" to the government in the post-9/11 world, to point out one guy in particular. The revolving door between intelligence/security professionals and high-paid security consultants has been spinning like a dervish since 2001. --Mr.98 (talk) 17:37, 12 May 2012 (UTC)

Backtracking a moment, I should point out that the existence of a disinformation campaign doesn't require that the allegation being suppressed is true. It is possible that a conspiratorial involvement by U.S. agencies or even by Russia or some other foreign country would become the object of such a campaign simply because it is seen as troublesome. For example, intelligence agencies after JFK's shooting might have wanted to downplay any possible role for Russia simply out of fear that minor politicians would start going on TV and calling for the nuking of Russia and ratchet up tensions to the point where a real nuclear exchange became more likely. Wnt (talk) 17:00, 11 May 2012 (UTC)

4) Considering that the WTC was built in the early 1970's, why would explosives have been built in back then ? This was long before al-Qaeda existed. StuRat (talk) 14:48, 11 May 2012 (UTC)

When George Bush designed the buildings in late 1960s, his plan was to be president in 2001. Sandboxer (talk) 15:18, 11 May 2012 (UTC)

 :-) StuRat (talk) 17:04, 11 May 2012 (UTC)

Once a couple of floors have let go, the dynamic impact loading so far exceeds the designed static loading capacity of the structure that there is no delay as the mass impacts the next floor. The kinetic energy released is ample to destroy just about everything. How many collapsed 100 (or even 10) story buildings has this firefighter seen?

As to the absurd idea of placing explosives in a building by design, I can assure you that architects and engineers spend their time more productively to assure that buildings protect their occupants (the relevant standard is called the "Life Safety Code"), and that nobody would countenance (or be insured for) such a measure. I'm pretty sure my professional liability insurance doesn't cover demolition explosives, nor did Minoru Yamasaki's. That of course ignores the general absurdity of the "controlled demolition" conspiracy theories, which unquestioningly assume that total demolition of WTC 1, 2, and as an afterthought WTC 7 were an obviously essential outcome, and not trusting that a couple of fueled 767s at high sonic speeds would create a satisfactory commotion, and ignoring that the Pentagon and Capitol weren't similarly leveled, and assuming that this conspiracy extends over decades and reaches into the highest levels. Acroterion (talk) 17:07, 11 May 2012 (UTC)

I have this theory that it was all caused by a bunch of religious nutters flying planes into buildings. HiLo48 (talk) 22:27, 11 May 2012 (UTC)

Nah. Too obvious. Remember the conspiracy theorists credo: The obvious explanation must always be discarded. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:51, 12 May 2012 (UTC)

I would have expected a debris field around the building, with a great many objects tossed some distance from the building, as things collide and columns buckle. and not all ground to powder under the main footprint of the building. Edison (talk) 04:01, 12 May 2012 (UTC)

I wouldn't. We had no reason to know what to expect. It was a one-off experiment, one we're not likely to reproduce any time soon. It hadn't been done before, and now we know what happens when a bunch of religious nutters fly planes into buildings like that. HiLo48 (talk) 04:16, 12 May 2012 (UTC)

The towers came straight down, piling on each other, and there were plenty of nearby buildings (at least one of which also collapsed later in the day) to kind of "contain" the debris, so the stuff that was scattered tended to be dusty (and a fair amount of it toxic - asbestos, maybe?) ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:43, 12 May 2012 (UTC)

Many times a tornado will destroy a house and countless small objects go missing, never to be seen again. And that's without millions of tons falling on them. If nothing else, the WTC attacks confirmed that they way they built it, which seemed so nifty at the time, with the exterior being the primary support, was a possibly fatal design decision. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:39, 12 May 2012 (UTC)

Hmmm, we don't have much to compare it with. For all we know, if it had one major support beam in the middle the terrorists would have taken it down with the van bomb. Or if were a visibly tougher building, maybe they'd have crashed the plane into the Empire State building instead and taken it down immediately with many more fatalities. We're so far out into anecdotal data here, no real experiments possible, it's impossible to say what would or wouldn't have been best to do at the engineering level. Wnt (talk) 23:47, 12 May 2012 (UTC)

WTC 1 and WTC 2 did not fall straight down in a neat pile. They collapsed on top of a dozen neighboring buildings. One building was an immediate total loss, and several others were damaged beyond repair. The towers did not turn into dust; trucks carried steel and concrete from the site for months. 88.114.124.228 (talk) 15:45, 12 May 2012 (UTC)

Yes, the surrounding buildings took much of the hit of the collapse (including the building across the street that collapsed later in the day). The dust cloud funneled through the surrounding streets. One thing to keep in mind is that in the cubic volume of any office, typically there's going to be a fair amount of "air". Obviously, when a 100-story building pancakes down, a lot of that air is going to be pushed out, leaving just the solid rubble. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:34, 12 May 2012 (UTC)

A significant amount (by mass, if not by volume) is also liquid (water in the plumbing, etc.). That would either drain away or evaporate, in short order, after the collapse. StuRat (talk) 23:53, 12 May 2012 (UTC)

Regarding 3, the explosion on the 8th floor: an emergency responder (firefighter or whatever) reported that he heard two explosions around this floor, so it's very plausible that indeed some explosions happened. The building had emergency power systems, powered by diesel fuel, and that were on separate floors, including the 8th. In the 8th floor there was one 275 gallon tank power generator.

Regarding 4: I'd rather say that lots of people would know it if it were true. There is not only the build-in during the constructing, but you'll have to take care that no one find the explosives during a renovation. OsmanRF34 (talk) 22:08, 12 May 2012 (UTC)

These conspiracy theories all seem to center around the way the buildings pancaked and crumbled. They assume that the buildings were properly constructed in the first place. My experience tells me that properly mixed concrete does not begin to deteriorate for something like a hundred years. properly mixed concrete tends ,when demolished, to break into large pieces held together with rebar. substandard concrete tends to pulverise when impacted and has little flexural strength. I have not reseached who the building contractors were and I'm guessing it was government funded. It is not unknown for contractors to pocket large sums of money on the back of substandard fraudulent construction. Amongst all the hype,furor and investigation, has there been one word investigating the construction. A scenario like that would certainly warrent some smoke screen from influential freinds.190.56.115.245 (talk) 00:47, 13 May 2012 (UTC)

The building was designed to 'pancake.' What would you prefer, it falling to any side in a highly populated area? And it wasn't converted into dust (as the conspiracy theorist say). And the issue was not the quality of the construction of the building. It could withstand a small ṕlane crashing, but a full-loaded jetliner is too much to any building. OsmanRF34 (talk) —Preceding undated comment added 12:09, 13 May 2012 (UTC).

How about this: the experts have said that the steel columns at the core of the building should have halted the collapse, and directed the force outward. Since the building was stronger in the core than toward the edges, the edges would have been falling faster. This should cause the collapse to lose momentum by redirecting falling debris outward instead of mostly downward. In the least, the floors should have pancaked around the columns, the violent vibrations of the bare columns should have twisted the collapsing building off the vertical and dragged it over, instead of it falling perfectly downward. The collision also caused assymmetric damage crosswise, even a small lag in failure would translate into an amplified effect visible further down the collapse. Plasmic Physics (talk) 01:39, 14 May 2012 (UTC)

Why is it that a demolision takes months to so carefully plan to ensure that a building falls as perfect as possible downward, when in this case it just happens naturally? Plasmic Physics (talk) 01:44, 14 May 2012 (UTC)

Well, a demolition doesn't want a building to probably fall perfectly downward! 9/11 shows that they managed to fall straight down on their own twice, but nobody knows what would happen on a third try. More to the point, the collapse of a very tall building will tend to be qualitatively different, because the downward force and moment of inertia is so much greater. Maybe if the fire burned away one whole edge things would have been different, but with everything failing more or less at once as whole floors were on fire ... it probably tends to be pretty symmetrical. Wnt (talk) 03:58, 14 May 2012 (UTC)

A controlled demolition would need to be a lot cleaner than that, or they would all be sued for the damages to the nearby buildings. Note that the same design features which keep buildings from falling over sideways while intact also work (somewhat), when the building is no longer intact, to keep the debris from falling over sideways. StuRat (talk) 04:11, 14 May 2012 (UTC)

If it was a covert demolition, then it would be kept out of the books and no one could be sued; there needs to be a balance between minimising collateral damage and maximising believability. I don't quite understand your second statement. Plasmic Physics (talk) 04:26, 14 May 2012 (UTC)

It's a question of stability. Let's consider an unstable design, like an inverted pyramid. That might very well fall over sideways, either while intact or when demolished. StuRat (talk) 05:26, 14 May 2012 (UTC)

That's not making sense - it does not take into account the assymetrical damage to the design. Plasmic Physics (talk) 06:06, 14 May 2012 (UTC)

When a ship sinks, the design that kept it unright while afloat does not neccessarily keep it upright while it sinks. Ships often list as they sink. Plasmic Physics (talk) 06:09, 14 May 2012 (UTC)

A ship with damage to one side fills with water on that side, which can weigh more than the ship. Not so with buildings. StuRat (talk) 06:46, 14 May 2012 (UTC)

A building with damage to one side weakens on that side, which can collapse before the other side. Plasmic Physics (talk) 07:08, 14 May 2012 (UTC)

Ah, but was the damage to one side? It would be one thing if a few floors of the WTC were two huge auditoriums, and one was full of plane and jet fuel while the other was empty. Then you'd expect the beams on one side to bend and give way, and the other to stay firm. But in truth, the jet fuel poured all over, some even flaming down the central elevator shaft AFAIK. It was more or less evenly distributed. Then the heat builds through hundreds of degrees, and the whole floors caught in flame (as the pattern of smoke indicated). The heat then increased much hotter than that. So it was a very uniform heating throughout the entire floor, not one calculated to put a strong push to send the top one way or another. And remember, the top had a huge amount of push going straight down - and no force at all to make it turn and flip sideways. Where would all that force come from to whirl around a fair-sized skyscraper (which is what the top of the WTC is) and to do so in only a few seconds or less between the time when it held firmly and when it had totally given way? Wnt (talk) 20:42, 14 May 2012 (UTC)

Columns closer to the impact zone should have collapsed before the columns further out, perhaps miliseconds apart. Much like a zipper effect. Even a small time difference between one side of collumns collapsing before the other, would cause a torque effect. Gravity v.s. a small support force acting around a fulcrum should produce a twisting, meaning most of the debris should fall off one side. Plasmic Physics (talk) 23:28, 14 May 2012 (UTC)

Well, here's the root of the problem: I don't see it that way at all. The sideways force shouldn't exceed that of gravity (shouldn't come near it, really) and milliseconds aren't enough time for gravity to move the building significantly. By the time it starts really moving ... it's moving down. Wnt (talk) 19:44, 15 May 2012 (UTC)

You're all repeating a common falsehood: the south tower did not fall straight down (watch for yourself); it fell a long way to the left (in that video.... I think that's eastward). Makes a lot of sense, since that's the side the plane hit the tower on.-RunningOnBrains^(talk) 02:01, 16 May 2012 (UTC)

But I guess that doesn't matter anyway. 9/11 "truthers" (BIG emphasis on the quotes) are all about distrusting the man/government/illuminati/whoever they think runs the world. You can poke a thousand different holes in their "theories", but they'll just adapt it and cherry-pick their evidence to find some way that the official story doesn't quite add up. Just like the "where's the plane" Pentagon garbage (fyi, it's right here), anyone who takes an honest look at all the facts would see that no other explanation than the official one makes even a small amount of sense (I'll allow for some slight plausible variations, like there were insiders in the government helping it along, but even that seems highly unlikely).-RunningOnBrains^(talk) 02:11, 16 May 2012 (UTC)

(edit conflict)I didn't say that there was a sideways force. The miliseconds between one side of the building and the other side is what is most important, not the difference between individual columns.

_________       ________         _____ _ _ _
|||||||||       ||||||||>       ////>>>.....     . . . . .
|||||||||       |||||||> >      ///>>.......     .. ... . . .
|||||||||       ||||||> >>      //>..... . .    .. .. . . . .     . . . . .
*********       ****-----       ----..... .     ........ . . .  .. . ... .. .
|||||||||       |||||||||       |||>>>---       ----..... . .   .. . . .. . .      . . ..
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Plasmic Physics (talk) 02:37, 16 May 2012 (UTC)

What about the other scenarion I described above?

_________        _______
|||||||||       <|||||||>       .........
|||||||||       <<|||||>>       .........           .
|||||||||       <<<|||>>>       .........         .....
*********       ---------       .........        .......          . . .
|||||||||       |||||||||      ..--H-H--..      ...H.H...       ...H.H...          H H
|||||||||       |||||||||       <|||||||>      ..--H-H--..     ....H.H....      ...H.H...
|||||||||       |||||||||       |||||||||      .<<|||||>>.    ....*H*H*....   ....*H*H*....
|||||||||       |||||||||       |||||||||       \|||||||/     . <*|||||*> .  .. .*|||||*. ..
|||||||||       |||||||||       |||||||||       |||||||||     . ||||||||| .  .. *|||||||* ..
|||||||||       |||||||||       |||||||||       |||||||||       |||||||||    .  |||||||||  .
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Plasmic Physics (talk) 11:39, 16 May 2012 (UTC)

Both your scenarios diagrammed above are what I would call "falling straight down" As Runningonbrains put it, the one tower fell "a long way" to the left. Maybe relative to a house trailer, yes, but relative to the size of the building? That's what I call "practically straight down". Same as your little particles in the first cartoon. Where do you think they're going to go, sailing away into the sunset, finding a building even further than WTC 7 to land on? No, they're going to do what isolated bits of stuff hanging over mid-air do, which is to fall down. Wnt (talk) 19:26, 16 May 2012 (UTC)

Agreed. If you consider how fast a particle would need to be moving sideways, even in a vacuum, to go, say, the height of the building sideways before hitting the ground, it would be a very high speed. Once you add the effects of wind resistance, collisions with other falling particles, and collisions with nearby buildings, going that far sideways becomes even less likely. StuRat (talk) 23:31, 16 May 2012 (UTC)

The second scenario supposes that the momentum of the collapse is redirected outward, effectively losing strength in the downward direction, halting the collapse. This should result in a pencil point.

As a reminder: these are not my scenarios. Plasmic Physics (talk) 01:41, 17 May 2012 (UTC)

Read Collapse_of_the_World_Trade_Center#The_collapse_mechanism, then come back if it still isn't clear. -RunningOnBrains^(talk) 01:55, 17 May 2012 (UTC)

That is exactly the mechanism that is being contested. Plasmic Physics (talk) 02:59, 17 May 2012 (UTC)

It explains quite clearly why your scenarios don't make sense. Even a single floor collapsing imparts forces 30-times the static force on the floors below, more than enough to progressively buckle the entire structure quite quickly. To be honest you've made such varying claims throughout this thread that I don't even know quite what you're arguing anymore. You make vague claims about "the experts" saying this and that but it's all heresay, and I doubt it is even partially true.

It is completely ludicrous to assert that the towers fell in any manner than has been already described in detail. Do you actually have a question? Or are you just trying to get the last word in this discussion?-RunningOnBrains^(talk) 03:42, 17 May 2012 (UTC)

It does not explain the second scenario. You're missing the point, progressive buckling ignores the design of the building. I'm asking why it should make more sense than the second scenario. Plasmic Physics (talk) 04:26, 17 May 2012 (UTC)

Transitional relativity ?

Hello,

does someone know if "transitional relativity" exists outside of Star Trek ? If so, what is it anyway?

Thank you. 194.199.79.181 (talk) 13:30, 11 May 2012 (UTC)

I can find no reference to 'transitional relativity' in science that does not relate to that single throwaway Star Trek gag, save for one book review that appeared in Nature in 1969: [4]. In that instance, the term is not being used to describe a particular branch of relativity, but simply to describe the type of textbook. That is, it is a textbook about the theory of relativity that attempts to bridge the transition between the way the subject is taught in (secondary, or high) schools and the way that it is presented in universities; it is the textbook that is transitional, not the relativity.

Additionally, there are a few references to 'transitional relativity' in contract law. TenOfAllTrades(talk) 15:15, 11 May 2012 (UTC)

Digging to Vesta's iron core

I just read that Vesta has an iron core with radius 107 to 113 km [5]; the protoplanet has overall dimensions of "572.6×557.2×446.4 km" as our article summarizes this (I can't access the original report at the moment, despite how much the taxpayers paid for this probe...). So depending on circumstances it is possible that a 100-150 km hole down into Vesta might get you to the very boundary of a frozen iron core. Vesta has about 0.022 g gravity (somewhere...) so the pressure at that depth would be something like a 2 km hole on Earth, which is to say, survivable. Whether there's a hope for some Krubera Cave with a correspondingly greater depth, going all the way down to the core boundary, well... in sci fi there may be. ;) And admittedly boring a 100 km hole, no matter how low the gravity, would be awfully ambitious for the human presence in space.

Nonetheless, suppose we could get down to this frozen core boundary. What would we find? Would there be big chunks of exotic mineral ores that are lighter than iron but heavier than all normal rock? Fields of diamonds like something out of Clarke's Jupiter? Maybe even liquid water and life, pressurized by the vast downward distance and heated by residual radioactivity? Wnt (talk) 18:39, 11 May 2012 (UTC)

Just as a note, Science (the journal) is a private company, that's why you can't access it, but you should be able to arrange a copy through your local public library, or if not any local university probably has access. Also all data collected by government-funded missions like NASA is in the public domain, so if you wrote them asking for data you could get it (although it might be a bit overwhelming if you didn't know what you were looking for). If you want to complain about access to scientific data, try dealing with the Europeans...they're heartless bastards who keep their science under lock and key. America is pretty much the only country in the world where scientific data is freely shared. -RunningOnBrains^(talk) 19:50, 12 May 2012 (UTC)

Even if it was packed with diamonds the cost of returning them to Earth would be far more than they are worth. This is especially true since we can create diamond in labs these days. StuRat (talk) 21:29, 11 May 2012 (UTC)

Oh, I know - especially diamonds, which are overvalued - but it could be a pretty visual image. I'm wondering what is down there, whether it's anything special. But Actually, based on how diamonds form, I suppose it's very very improbable, since the pressure needed is actually greater than Vesta could manage, I think! Unless they formed during some past collision and sank when it was molten or something, but then, I suppose they'd be microscopic, and they wouldn't sink anyway. Wnt (talk) 02:10, 12 May 2012 (UTC)

Cobra Mist

Have there ever been plausible suggestions for the cause of the Dopler-shifted noise that hampered and ultimately led to the shutting down of the Cobra Mist over-the-horizon radar system in 1973? And did this system cause the same interference as the Russian Woodpecker (and if not, why not)? The transcript of the report "The Enigma of the AN/FPS-95 OTH Radar (U)" can be found here, second half of the page. (It's a UFO site, but the transcripts seem genuine, the source in the Cobra Mist article only has the odd numbered pages). Ssscienccce (talk) 20:11, 11 May 2012 (UTC)

Not specifically about that radar, but noise is a common problem with all radar. In particular, things like water vapor droplets or flocks of birds close to the radar show up as much as large objects far from the radar. This problem is usually solved by attenuating the signal returned from nearby objects, so they once again are in proportion to returns from object far from the radar. I don't know if this was done with the Cobra Mist system. StuRat (talk) 21:27, 11 May 2012 (UTC)

Using pulsed wave signals, reflections from nearby objects would be filtered out on a timer basis. The main problem was the amount of ground backscatter, given the long distance the signal traveled (1000 to 3000km), it would receive the ground reflection of an area of maybe 1000 km², while a typical target would present a surface area of only 30 m². The pulse Doppler radar signal processor was required to suppress the ground backscatter by 85 to 90 dB relative to aircraft returns; for that, the transmitter and receiver were designed to have a very large linear dynamic range. Basically they depended on accurate doppler shift filtering to remove the ground backscatter, but for some reason the received signal contained a lot of noise in all the doppler shift ranges. It was as if they received signals from thousands of targets all traveling at different speeds. I found this document suggesting the noise could be due to range-discrete meteor echoes or to range-dispersive auroral scatterers. They conclude: The spectral behavior of the meteor-nose echo agrees very well with that of the FPS-95 noise. Theoretical tenets as well as experimental evidence force the conclusion that the FPS-95 noise is produced in part by meteor-nose echoes. However, it doesn't explain why the phenomenon was seen only over land, not over water, and the writers of the "Enigma" paper do not accept this conclusion. Ssscienccce (talk) 14:06, 12 May 2012 (UTC)

What is it that is constantly moving in large volumes over land, and never over sea? Why, road traffic of course! A single truck could be large enough to produce a detectable echo. On freeways and highways, you get clumps of vehicles moving together, and together they could be a large enough target. As traffic cops using radar know, when you have two directions on a road, you can get echos aparently indicating speeds that are multiples of the true traffic speed, as the bean refects from one vehicle to another, adding the speed of each. Please tell me that folks who spent vast sums of money knew this, and dealt with it somehow. Or have I missed something? Keit120.145.7.207 (talk) 12:51, 13 May 2012 (UTC)

That's a sensible answer! We can't have those! Space aliens are far more likely! Tevildo (talk) 16:45, 13 May 2012 (UTC)

Good point, they don't mention that in the report. Maybe the timing of the noise or the calculated speed wasn't consistent with ground targets, I don't know. Looking at the graphs in the report, the noise levels peak before and after the ground backscatter, maybe that's why they think it must occur when the waves reflect against the ionosphere. I must say their initial expectations were a bit high, there was talk about maybe later, if all went well, increasing the range with a second bounce of the ionosphere. Not sure if they meant ionosphere-ionosphere-target or ionosphere-ground-ionosphere-target ... Ssscienccce (talk) 21:17, 13 May 2012 (UTC)

Eating pearls

Are there any health benefits or risks involved in swallowing pearls? For example, if one is embedded in an oyster and swallowed by accident.

Also, how hard is a pearl? Would biting on one be more likely to break the pearl or a tooth?

(I tried to search for a reference desk item that is relevant to the health question. Got some about Pearl Harbor and "pearls before swine" but nothing relevant.)

Thanks, Wanderer57 (talk) 21:01, 11 May 2012 (UTC)

You could choke on a large pearl. If you manage to swallow it I'd expect it to be dissolved by stomach acid. I'd also expect it to break before your teeth, possible leaving sharp bits that could cut you. StuRat (talk) 21:19, 11 May 2012 (UTC)

If you drink a goblet of wine in which a pearl has been dissolved, make sure you know the motives of the person who dissolved it. --Trovatore (talk) 21:46, 11 May 2012 (UTC)

Pearl is 2.5 - 4.5 on Moh's scale of hardness, which is pretty soft. Made almost entirely of calcium carbonate and thus readily dissolvable in the digestive system as stated above. If you have swallowed it then the risk of choking is virtually zero. I can't agree that there are any health benefits or dangers. Richard Avery (talk) 08:09, 12 May 2012 (UTC)

Well, the record seems to show that it is very hazardous, if the provider of the pearl killed your father, his brother the king, and took over your father's throne and queen. Although in that situation you also need to watch out for poisoned rapiers. --Trovatore (talk) 21:54, 12 May 2012 (UTC)

Drinking pearls dissolved in wine or vinegar seems to have been a well-known (if rarely done) act of ostentation. Cleopatra performed the trick to impress Anthony.[6] Caligula was another pearl drinker, and Sir Thomas Gresham is said to have ground up and drunk a pearl worth £15,000 to impress the Spanish Ambassador according to this source or in drinking the health of Queen Elizabeth I when she visited his new Royal Exchange according to Brewers. Alansplodge (talk) 09:01, 12 May 2012 (UTC)

The Mohs scale is a measure of scratch hardness (that is, you can tell if your teeth will scratch the pearl or vice-versa). If you want to estimate the odds of damage to your teeth, you want an indentation hardness test or you want to compare the relative compression strengths (or, given the leverages and directions of force involved, you might need to factor in tensile strength). --Carnildo (talk) 01:42, 16 May 2012 (UTC)

Typically, a pearl is wrapped around a bit of sand from the bottom of the ocean. If that's something you want to consume, knock yourself out! ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:46, 12 May 2012 (UTC)

It could perhaps help digestion as a stomach stone. Count Iblis (talk) 02:18, 13 May 2012 (UTC)

May 12

Rate data for dissociation & recombination reactions

For chemical reactions of the form A + A + M → A₂ + M and the reverse A₂ + M → A + A + M, there is a range of published rate parameters (ie values to insert into arrhenious and modified arrhenious reactions) for all sorts of elements A. But the published data is restricted to only a few element/molecules M (the bath gas in lab tests) Almost entirely, M in published data seems restricted to N₂ and the noble gasses Ar, He, and Xe (Noble gasses are not of course terribly useful). Sometimes, but not always, you see M set to A or A₂, which is most useful. Sometimes you see CO₂. Is there a usable way to predict approximate rate constants where M is A, A2 or even useful things like O, O₂, N, and N₂, given rate constants for published values of M? Ratbone121.215.159.87 (talk) 15:00, 12 May 2012 (UTC)

Have you tried http://kinetics.nist.gov/kinetics/ ? Ssscienccce (talk) 16:03, 12 May 2012 (UTC)

Yes, of course. I've used it enough to know that it has many inconsistencies, traps for young players, and some errors. It's main value is that for any reaction in the database, it gives a list of references to look up. It is no help whatsoever with the question I asked. Ratbone121.215.147.93 (talk) 03:17, 13 May 2012 (UTC)

You probably won't find data for M = O (oxygen atom), except for A = O, because the O will have a greater affinity for A than another A. In other words the rate for A + A + O → A₂ + O will be very much lower than the rate for A + A + O → A + AO, and the reaction A + O + O → A + O₂, making product from the first reaction insignificant and thereby difficult to measure before all the O is used up. Keit120.145.7.207 (talk) 12:37, 13 May 2012 (UTC)

Lift controls

What happens if you press the button for the floor, on which the lift is parked with closed doors? --84.61.181.19 (talk) 16:33, 12 May 2012 (UTC)

What happens if you press the button for the floor, on which the lift closes its doors? --84.61.181.19 (talk) 16:36, 12 May 2012 (UTC)

What is the difference between pressing the door open button, and pressing the button for the floor you are currently on? --84.61.181.19 (talk) 16:39, 12 May 2012 (UTC)

I would guess that the answers depend on the control software for that particular lift, and on whether you are inside or outside. Why not experiment on real lifts and report your findings here? Dbfirs 16:41, 12 May 2012 (UTC)

What is the difference between old and new lifts in respect of my questions? --84.61.181.19 (talk) 16:42, 12 May 2012 (UTC)

In really old lifts, you open the door yourself, pushing the current floor won't do anything since the door stays unlocked until you select another floor, or someone on another floor calls the lift. Ssscienccce (talk) 17:26, 12 May 2012 (UTC)

It certainly depends on the elevator, but in my experience, if you're on a floor and you push the button for that floor, nothing happens, the elevator just sits there. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:30, 12 May 2012 (UTC)

FYI, the OP here has been elevated to the block house. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:42, 13 May 2012 (UTC)

What do these presumably space related acronyms mean?

Take a look at File:Mission_control_center.jpg and specifically the map of the earth; there are a bunch of regions on it - I've worked out that SAA is the south atlantic anomaly, and am pretty sure that the biggest ovals are going to be to do with daylight/darkness, but am not sure what the other things are. Google doesn't seem to be of help. The acronyms from West to East, so far as I can make them out (although I encourage you to look at the image) are:

• T???SW
• HTSS
• SAA (identified as South Atlantic Anomaly
• ShLK
• ????
• RDE
• KiPA
• ULDA
• USKA
• PPKA

Egg Centric 19:07, 12 May 2012 (UTC)

I'll admit, I'm stumped. At first I thought they looked to be the orbits of various quasi-geostationary satellites relative to the ground. Yes, geostationary satellites aren't perfectly geostationary, they typically wobble([7]) though these seem a lot more extreme than the typical wobble. But I agree with your assessment of SAA being South-Atlantic Anomaly, which makes my theory less plausible. I can speculate that maybe HTSS is some Hawaiian high-altitude observing station, as would be the various circles over Russia. Unfortunately I can't find many references to the above acronyms that seem relevant. -RunningOnBrains^(talk) 20:28, 12 May 2012 (UTC)

The Kaena Point Satellite Tracking Station is the site of the Hawaii Tracking Station or HTS, but that doesn't explain the extra "S". -- ToE 20:58, 12 May 2012 (UTC)

I agree that the large oval-like light and dark regions are daylight. The shape and size looks like File:Daylight.png (the lede image at Daylight). Even the specific part that is daytime makes sense: the Mission Control clock ("GMT" display top just to the left-of-center) is "063:15:00:44+" (3pm in England), in keeping with the "becomes dark" line about 30° east of England (about 2 hours of daytime left). DMacks (talk) 21:50, 12 May 2012 (UTC)

Searching [8] sniffs out a link at NASA, but I don't know what kind of file it is. (I dunno... lot of random noise when viewed as text... I might be Helen Keller reading the stucco wall here) Wnt (talk) 23:36, 12 May 2012 (UTC)

Searching for things related to the "PPKA" site, two interesting similars are "PKA" (acronym for the Russian Federal Space Agency) and Petropavlovsk-Kamchatsky, which is definitely in the correct location for that label. But this is definitely my WP:OR here. DMacks (talk) 03:22, 13 May 2012 (UTC)

Alright, found some more concrete information. ISS Ground Stations and Capabilities lists a bunch of Russian space-tracking installations, including things with identifiers "ULD", "PPK" (agrees with the lead I found by an unrelated search method), and "KLD". Soviet/Russian OKIK Ground Station Sites lists more sites with less information about them. DMacks (talk) 07:20, 13 May 2012 (UTC)

I suppose it goes without saying that "ShLK" is a Russian acronym of some sort (Sh is a single letter in Russian, Ш). --Mr.98 (talk) 15:13, 13 May 2012 (UTC)

The yellow circles with yellow letters in the upper right are indeed Russian ground stations. HTSS is a ground station in Hawaii. SAA is indeed the South Atlantic Anomaly. The blue letters in the center left are T171W, which is a TDRS satellite located at 171 degrees west. There are yellow letters over South America for TDRS 46 as well. anonymous6494 18:49, 14 May 2012 (UTC)

Herschel and life on the Moon, etc

Mormon cosmology says "Such beliefs were common in the nineteenth century and were even considered to be "scientific fact" by many at the time. For example, William Herschel, the discoverer of the planet Uranus, argued "[w]ho can say that it is not extremely probable, nay beyond doubt, that there must be inhabitants on the Moon of some kind or another?" Furthermore, "he thought it possible that there was a region below the Sun's fiery surface where men might live, and he regarded the existence of life on the Moon as 'an absolute certainty.'"

William Herschel says "Despite his numerous important scientific discoveries, Herschel was not averse to wild speculation. In particular, he believed every planet was inhabited,[16] even the Sun..."

So the first says that it was considered scientific fact by many. The second says that it was a wild speculation. Which is more accurate? And will someone correct one of the articles? Bubba73 ^{You talkin' to me?} 19:12, 12 May 2012 (UTC)

Those can both be true. Consider that today, the Earth having been created a few thousand years ago is "considered scientific fact by many". They are completely wrong, of course, and this belief has nothing whatsoever to do with science. StuRat (talk) 22:08, 12 May 2012 (UTC)

Did many scientists consider it a scientific fact that there was life on the Moon, etc? That seems to be what it is implying. Bubba73 ^{You talkin' to me?} 23:25, 12 May 2012 (UTC)

Note that the phrase "scientific fact" was in quotation marks. Anonymous.translator (talk) 01:44, 13 May 2012 (UTC)

I suspect "scientific fact" is too strong a phrase, quotation marks or none. It would have likely been considered speculation. Perhaps not "wild" speculation. It would have been considered likely that other worlds had life — as it is considered likely today, though we now know that the parameters for life on a planet are considerably more specific than they would have known in the 19th century. But even as late as the mid-20th century, the idea that Mars might be populated with plants (if not intelligent life) was considered not an impossible prospect. (Today, of course, the possibilities of life on Mars are reduced to looking for bacteria-like organisms.) Anyway, both the scare-quoted "scientific fact" and the "wild" seem like things worth demanding a reference for. "Wild" is not neutral in any case; and I would want to see someone asserting the "fact" that there was life on the Moon. --Mr.98 (talk) 15:01, 13 May 2012 (UTC)

I agree with you. Bubba73 ^{You talkin' to me?} 18:46, 13 May 2012 (UTC)

The Herschel quote technically belongs to the 18th Century - it was made in a letter to the Astronomer Royal Nevil Maskelyne according to this. However the idea of Cosmic pluralism wasn't a fringe idea in the 19th Century. Not that his writings quite live up to scientific rigour perhaps, but one writer that does spring to mind in the 19th Century is Thomas Dick, who I came across in the Great Moon Hoax article. His 1826 book The Christian Philosopher, or the Connexion of Science and Philosophy with Religion suggesting life on the Moon was widely known, in both Britain and the United States; whether it had any influence on Joseph Smith, I don't know. In another book published in 1837, Celestial scenery: or, The wonders of the planetary system displayed; illustrating the perfections of the deity and a plurality of world, basing his estimates on the population density of Britain and scaling accordingly, he estimated the population of the Moon to be 4,200,000,000, the population of Saturn's rings to be 8 trillion and the population of the Solar System as a whole to be 21 billion (give or take). (These figures taken from this book). FlowerpotmaN·(t) 23:17, 13 May 2012 (UTC)

May 13

While I know that it's a myth that you can stop a moving car...

...by shooting a .44 Magnum round though the engine block (did that belief come from a line in the film Taxi Driver, or was it one of the Dirty Harry movies - that people just picked up on?), is there any handgun cartridge at all that can actually do this? --95.150.167.241 (talk) 00:16, 13 May 2012 (UTC)

Technically, a .44 Magnum round could stop a car according to the law of conservation of momentum. However, a 1000 kg vehicle could only be going .0051 meters per second if the bullet was fired from exactly the opposite direction. Similar calculations could be done with other cartridges. Reaper Eternal (talk) 00:23, 13 May 2012 (UTC)

I guess it all depends on what you mean by "stop a car". If you mean stop it's forward movement immediately, it would be have to be going very slow, as noted above. If you mean to stop the engine, I don't think you're likely to cause much damage to the engine block. You could take out any number of critical components by chance, however. The fuel line, distributor, ECM, any number of wires, etc., could stop the engine almost immediately. However, this requires a lucky shot. If you are content to stop the car eventually, putting a hole in the radiator gives you a much bigger target. StuRat (talk) 02:17, 13 May 2012 (UTC)

Stopping a car with any speed would require a serious amount of force, enough to interrupt oil flow probably, or as mentioned above a very lucky shot. Puncturing the radiator, as mentioned, will lead to the engine eventually seizing, but will not be any sort of rapid stop. the largest production handgun in the world is the .500 S&W, which produces a stunning 2600 or more foot-pounds of force. This is nearly 700 Ft-lbs more than the puissant .454 Casull. If you were to assume that the round is similar to the indenter used in a Brinell scale test, then against a typical grey cast iron engine block, it would make an indent defined by: Brinell hardness = (2*force in Kgf) / ((pi * diameter) * (Diameter - Sqrt(Diameter^2 -Indentation^2))) in this case that would be 260 = (2 * 35946.2) / ((Pi * 12.7)(12.7- Sqrt(12.7 - D))). This simplifies to: 260 = 71892.4 / 39.8 * (12.7 - Sqrt(12.7 -d)). The simple answer is 12.55mm which is almost exactly 1/2 in. (one half inch is 12.7mm as seen above). Since the engine block is greater than .5 in. thick, it's unlikely the handgun bullet would penetrate. Since cast iron is fairly ductile it is unlikely to shatter, and it's unlikely to deform greatly from that impact. Keep in mind this is a best-case scenario with a full-caliber tungsten penetrator, like a military AP round.Ssscienccce (talk) 10:24, 13 May 2012 (UTC)

Don't count on a cast iron engine block (leaving aside that most are aluminium alloy these day) not shattering. I've seen more than one engine block with a dirty great hole in the side caused by a thrown conrod (caused by either incorrectly installed bigend bolts, or the conrod itself breaking). However, engines can continue to run under such conditions, if the driver can stand the horrible noise. And if you are shooting at him, he will. Keit120.145.7.207 (talk) 12:29, 13 May 2012 (UTC)

HominidMachinae (talk) 06:42, 13 May 2012 (UTC)

Your best bet would be having the engine destroy itself, since a turning engine has a lot more kinetic power than a bullet. Breaking the timing belt or a valve (if a bullet can reach there) would do serious damage. A bullet at the right spot can initiate catastrophic failure, I suspect.  ::I would think that hitting the gearbox might well (though not always) cause immediate locking of the damaged gears and hence transmission, but you'd probably need quite advanced automotive experience to know where it was on your particular target, and whether or not it was effectively shielded from your position. {The poster formerly known as 87.81.230.195} 90.197.66.211 (talk) 11:31, 13 May 2012 (UTC)

Two words: smart bullet. Of course, when a bullet has the plans of every car coded inside it and decides where to hit in a few microseconds, the days of allowing the pathetic human behind it to have a say when it is fired will soon come to an end. Wnt (talk) 15:16, 13 May 2012 (UTC)

Mythbusters kinda hit on this one a while back. They were doing a myth about phonebooks making a car bulletproof... until Carrie put a .50 caliber round through the engine block(episode). So, I'd say no, a handgun won't be able to pull it off. — The Hand That Feeds You:^Bite 21:15, 13 May 2012 (UTC)

Like I said above, no handgun round could do it, even with military ammo. However a .50 BMG round from a rifle was BUILT to take out light armor would do it handily. Vehicles are tougher than a lot of people give them credit for. Anything capable of taking out a vehicle will be military-grade and probably a squad-level weapon (IE a Boys AT rifle is about the smallest they get, and that thing is 70 pounds). HominidMachinae (talk) 23:10, 13 May 2012 (UTC)

How's about a .50 BMG round fired from a pistol? I believe that .50 BMG pistols have been built before - though probably only in numbers amounting to single digits by people who want to see what holding and firing a .50 BMG pistol looks/feels like. --Kurt Shaped Box (talk) 19:19, 14 May 2012 (UTC)

Rusting after burning

Why is it that metal seems to rust much quicker after it's been burned in a fire? Or is this just confirmation bias on my part? Dismas|^(talk) 01:27, 13 May 2012 (UTC)

How is that you've observed the rusting of scorched metal often enough that you observed patterns in it?? If it is because you live in a city that was recently a battlefield, I sincerely feel for you, but otherwise, that is kind of strange. ike9898 (talk) 01:46, 13 May 2012 (UTC)

Upon reading the question I immediately thought of the old campers' dictum (now strongly discouraged) in my country, Australia, of what to do with empty cans - Burn, bash and bury. As Tin can tells us, "Tin cans are made of tinplate (tin-coated steel)", and the burning removed the thin protective tin coating, thus allowing the steel to rust more quickly. If this response has nothing to do with the question, just ignore me. HiLo48 (talk) 01:56, 13 May 2012 (UTC)

That seems like the proper explanation, although I doubt if the tin melts entirely. More likely there are just holes created in it. The plastic lining on the inside may burn away entirely, however, exposing the inside to the elements. Another factor to consider is that cans, once burnt, might be left in a fire pit, where they are far more exposed to the elements (water, changing temps, etc.), than the intact can was whilst in a cupboard. StuRat (talk) 02:06, 13 May 2012 (UTC)

My guess would be that it would have rusted before being exposed to high temperatures had there not been some coating on its surface preventing its exposure to oxygen and water. Paint serves this purpose but perhaps other clear substances, the presence of which one may not be aware of, could have been present before heating but removed or damaged by heat. Bus stop (talk) 02:29, 13 May 2012 (UTC)

No, I don't live in a war zone. And it occurred to me to ask after seeing the rubble from a house down the road that had recently burned down. Someone had made a pile of all the appliances and other large metal objects that were taken from the home. Every bit of it was rusted. Off the top of my head, I remember seeing a sink, a water heater, what appeared to be a washer or dryer, a stove, a few mattress springs, and what appeared to be possibly a table saw. Since the fire, it's been rather dry here with the exception being a couple days this past week and, of course more localized, the spray from the fire hoses. The items were all covered in rust. Dismas|^(talk) 03:34, 13 May 2012 (UTC)

Protective coatings burning off (like paint, oil on tools..) or damaged by impact, moisture for days, chemicals in the water, galvanic corrosion if touching other metals. Ssscienccce (talk) 10:51, 13 May 2012 (UTC)

You know what the difference between burning and rusting is? Speed. Apply oxygen to iron using water as a catalyst, and you get rust. Apply oxygen to iron using heat to speed up the reaction rate, and you get rust. The ingredients are the same, the underlying chemical reaction is the same, and the end product (iron oxide) is the same. --Carnildo (talk) 01:51, 16 May 2012 (UTC)

Autism

Autism is described as being on a spectrum. Presumably 'profound autism' is one end of that spectrum. What is the other end of the spectrum? 'Extrely Nuerotypical'? ike9898 (talk) 01:42, 13 May 2012 (UTC)

People who have abnormally good social skills. Count Iblis (talk) 02:08, 13 May 2012 (UTC)

Asperger's syndrome is a mild form of autism, and then there is PDD-NOS and high-functioning autism. StuRat (talk) 02:26, 13 May 2012 (UTC)

Stu is onto it. A basic definition of autism is the reduced ability to see another's point of view. But the range of Autism is not on a line - it is multidimensional. As with most mental/pschological "problems", a highly intelligent individual can overcome the "problem" by consciously thinking about it and correcting his behaviour. In doing so, the individual may make his autism seem different. I've put the word "problem" in quotes because to a high functioning autistic, it is a matter of opinion whether it is a problem. There are fields of employment where autism actually helps. Wickwack121.221.89.38 (talk) 03:08, 13 May 2012 (UTC)

'Stu is onto it' == 'Stu is on the autistic spectrum'? ~~ — Preceding unsigned comment added by OsmanRF34 (talk • contribs) 12:13, 13 May 2012 (UTC)

I'm sitting on a spectrum ? I can't feel it down there. I'd love to discuss this further, but it's 5:19, which means it's time for me to rip up pieces of paper for no apparent reason. :-) StuRat (talk) 05:19, 14 May 2012 (UTC)

Well, I wouldn't know, but as his posts are friendly, and he never attacks other posters, I doubt it. Note that I said "onto it", NOT "on it". The meaning is quite different. Wickwack58.164.226.214 (talk) 14:35, 13 May 2012 (UTC)

There is a hypothesis floating around by a Bernard J. Crespi that autism and schizophrenia are at opposite ends of a neurological spectrum. He's been going on about this since at least 2008. You can find lots and lots of papers [9][10][11][12][13] etc. about genes that affect both autism and schizophrenia. The problem is, it's hard to really categorize the effect as "same" or "different"; often one or the other is more what you'd call "altered". So some people paint it as two disorders based on the same mechanism, this fellow says they are opposite - in biology, there is little real distinction between synonyms and antonyms!

The most intriguing way to settle the issue would be to put some autistic kids on low-dose LSD - not enough to have obvious trippy effects, but maybe enough to revert autism to normality, if LSD is "psychotomimetic", and if that is some effect opposite to autism. But naturally many things could go wrong in such an experiment and some may question its ethics. ;) Wnt (talk) 04:38, 13 May 2012 (UTC)

You must be joking. Autism, neither the effects, not the cause, is well understood, but it is clear that it is caused by a lack of something - possibly a full set of functioning mirror neurons http://en.wikipedia.org/wiki/Mirror_neuron, maybe that and/or something else. You won't correct that with any sort of drug, any more than you could correct blindness, due say to genetically damaged retinas, with drugs. With enough LSD, you could maybe get the subject to think he has vision though... If you give LSD to autistic people, what you can only get is two problems instead of one - socially inept people who can't think straight, and if enough, socially inept people who halucinate and suffere from delusions. Hardly an improvement. Scientific American had a couple of good articles on autism, the mainstream professional view of it, and the role of mirror neurons, in the last year or so. Wickwack124.178.183.79 (talk) 11:07, 13 May 2012 (UTC)

I don't see the evidence that something is missing - while there are indeed large-scale and permanent variations in autistic brain (the location in the cortex where processing is done, the disruption of the inferior olive, AFAIR), it is often the case in biology that very visible alterations to an organ are less important than small and reversible regulatory changes. I'm not entirely serious in the sense that the low-dose LSD experiment I proposed probably wouldn't work and would very likely be regarded as unethical; nonetheless, I think there's a chance it would be beneficial. Wnt (talk) 15:11, 13 May 2012 (UTC)

In 2002 Simon Baron-Cohen put forward a theory that autism is an extreme form of the male brain, and there is a more recent article here about it. So one answer to the question could be "maleness" (or, depending on whether you see gender as a continuum, "femaleness").--TammyMoet (talk) 09:46, 13 May 2012 (UTC)

In the medical field generally, and the psycology field especially, you can always, if you look, find some wizzo professor who has very different and even bizare views about something. Here in Australia, we had a, otherwise quite well respected, medical professor who kept claiming that smoking had no role in lung cancer. He got in the news from time to time until he got lung cancer and died. However, TammyMoet's link is interesting. Wickwack124.178.183.79 (talk) 11:07, 13 May 2012 (UTC)

[OP] So, would it be safe to say that a spectrum is a bad analogy for the range of autism and related conditions?ike9898 (talk) 13:02, 13 May 2012 (UTC)

Not at all. "Spectrum" is a good word for it. Just as we talk about light having a spectrum, meaning a range of colours, autism is a spectrum, because it encompasses a range of conditions. Not only because you can be mildly, moderately, or severely autistic, but because not all autistic people, even if they are of the same severity, will display the same limitations or advantages. It is multidimensional in impact, as I said. (Not forgeting that autism can be a disadvantage or an advantage depending on the circumstances the autistic finds himself in). Wickwack58.164.226.214 (talk) 14:29, 13 May 2012 (UTC)

1 year.

Earth 2 forms a ring centered on the Sun, located on the circle* of old Earth's orbit. Earth 2 is stabilized by its rotational motion at old Earth's orbital speed. Your job is to find a way of having seasons on the ring. The idea for producing seasons is to allow Earth 2 to oscillate in the direction of its axis, perpendicular to the plane of its ring. Assume that a line from the Sun to Earth 2 oscillates through 46° of angle, with the mid-plane of the oscillation containing the Sun. What is period of the oscillations, in units of years?

If the Sun is a perpendicular distance $x$ from the ring, I worked out the magnitude of force acting on the ring to be ${\frac {Gm_{sun}m_{E2}x}{(r^{2}+x^{2})^{\frac {3}{2}}}}$ which is approximately ${\frac {Gm_{sun}m_{E2}x}{r^{3}}}$ since $r$ is surely much bigger than $x$. It follows that the "spring constant" is ${\frac {Gm_{sun}m_{E2}}{r^{3}}}$ and the period of oscillation is therefore ${\frac {2\pi }{\sqrt {\frac {Gm_{sun}}{r^{3}}}}}$. I look up the numbers and substitute and get a result of a single year. Since the result needs to be given in years, I am suspicious of this result and may have made a mistake. Does anyone agree/disagree with what I have done? --Widener (talk) 01:52, 13 May 2012 (UTC)

*By the way, I am aware that it is actually an ellipse.

Would not the "spring constant" be negative (which will not sustain oscillation)? Wickwack121.221.89.38 (talk) 02:41, 13 May 2012 (UTC)

That would be under the interpretation that $F=kx$ rather than $F=-kx$. Widener (talk) 03:06, 13 May 2012 (UTC)

If I'm understanding the question correctly, is it not obvious that it will be a year? I don't see why you need to use any maths. Egg Centric 02:43, 13 May 2012 (UTC)

Assuming I've understood his text etc correctly, he's visualising a donut/toriod shaped earth that supposedly oscillates up and down its rotation axis. The real earth has seasons because its rotation axis is at an angle away from perpendicular to its' orbital plane, forcing the seasons to be the same period as the orbital period. Such a thing is inapplicable to a donut surrounding the sun. So he needs to calculate the period of this "new" mode of oscillation, which is not locked to the orbital period. It will not actually oscillate though. Wickwack121.221.89.38 (talk) 02:50, 13 May 2012 (UTC)

I was going to say that the oscillation could be made any arbitary period (and therefore presumably a year) by altering the amplitude but then noticed the 46 degree thing... I see the problem Egg Centric 16:13, 13 May 2012 (UTC)

(So presumably you don't want to model it as a ring, just model it as a point mass with a centre of gravity which happens to pass through the sun during the oscillation, which means the equations will be very simple. Although it's a decade since I've done any mechanics, as this thought probably demonstrates) Egg Centric 16:15, 13 May 2012 (UTC)

The statement that r is much bigger than x is not valid. It's bigger, but not enough bigger to make the approximation valid. The max value of x/r is tangent(23 degrees), which is about 0.42. Looie496 (talk) 03:07, 13 May 2012 (UTC)

I don't think this will actually work - the varying distance from the ring to the Sun means the idea of stabilising it by having it revolve at orbital speed doesn't work. The centripetal force from the Sun's gravity won't balance the centrifugal force from the revolution, since the revolution is constant and the relevant component of the Sun's gravity isn't. That means you're going to get internal forces within the ring, which will rip it apart (unless it is made of some hypothetical super-strong material). --Tango (talk) 19:32, 13 May 2012 (UTC)

I don't know what "stabilized" means here; rotation doesn't affect the tendency of a Ringworld to drift into the sun. —Tamfang (talk) 03:20, 14 May 2012 (UTC)

By the way, this sounds like a homework question to me, presumably for calculus class. Ah well, too late now. ;) Indeed, the Ringworld is unstable, but only small attitude jets are said to be necessary. The oscillation along the axis would be unrelated to its instability from side to side.

As for the question, the Ringworld is simply a vertical wall to hold its bits in place. Mass cancels out and is irrelevant. A particle of the ring is accelerated toward the sun at G m_sun/sqrt(x²+r_earth²), but toward the midline at that multiplied by x/sqrt(x²+r_earth²). So you have to integrate dx/dt for G m_sun x/(x²+r_earth²), I think... And I don't think that you can assume x is much smaller than r_earth, or else you wouldn't get seasons from it. Besides, knowing/looking up/figuring out this integral is presumably the point of the assignment. ;) Wnt (talk) 04:30, 14 May 2012 (UTC)

Its not likely to be homework, becasue as such it would be a trick question - its not solvable because it is not oscillatory. In any case, its ok, because this OP showed us he had a go at working it out. Wickwack124.178.138.77 (talk) 06:02, 14 May 2012 (UTC)

If it doesn't oscillate, what does it do? It's not an escape trajectory (you can imagine it starting at rest at one of the mid-winter/mid-summer positions, so the total energy must be negative), and there isn't enough going on for it to be on a bounded but non-periodic trajectory (it essentially boils down to a two-body problem). It's not quite simple harmonic motion (the restoring force is inverse square, rather than a simple linear force) but it's still an oscillation. --Tango (talk) 18:24, 14 May 2012 (UTC)

It is an escape trajectory, as the "restoring force" for oscillation perpendicular to the rotation axis is negative. Unless I've mis-understood the OP's question. Please re-read the original question, my third post (begins "assuming I've understood....". and then tell us what you think. Your previous posts (and possible EggCentric's) are sort of/partly consistent with a different interpretation - that of a toriod (or bottomless & topless thin drum) with its centre of gravity in eliptic orbit about the sun. That will give seasons, but is not consistent with the OP's explanatory words to his question. Wickwack120.145.187.143 (talk) 00:54, 15 May 2012 (UTC)

I agree with Tango that you have misunderstood the question. The idea is that you have a ring, with the sun at the center, then you give it an "upward" push. It slows down until the angle of the face of the ring and the sun is 23 degrees, then accelerates back "downwards" until it reaches the ecliptic again and starts decelerating, then at -23 degrees it accelerates "upward" again. I think you've gotten lost in the equations, because it's simple to see that it will be an oscillator if you look at the problem practically :)

And to the OP: As a rough check of your calculations, you could take the freefall time of a point mass with the same mass as the ring at an equivalent distance directly above the sun, then quadruple it to get the time for a full oscillation. Too lazy to do the calculations myself, but a quick back-of-the-envelope calculation tells me the oscillation period should be on the order of hours-days, not years. -RunningOnBrains^(talk) 03:53, 15 May 2012 (UTC)

Agreed. I think Wickwack is reliving the glory days of (Larry Niven says, MIT students chanting "The Ringworld is unstable". But here the Ringworld is being pushed perpendicular to the direction it was moving in Ringworld Engineers. Wnt (talk) 19:39, 15 May 2012 (UTC)

Unfortunately no glory days. I've had another think, prompted by Runningonbrains's method, and decided that it will oscillate after all. Wickwack124.178.42.68 (talk) 01:03, 16 May 2012 (UTC)

Why is CO not the anhydride of formic acid?

The acid's article does not describe why formic acid behaves differently from carbonic acid, which I viewed as simply a higher oxyacid of carbon.--Jasper Deng (talk) 03:30, 13 May 2012 (UTC)

I think you might be mis-reading how carbonic acid behaves when it dehydates: its reaction is O=C(OH)₂→O=C=O, which is a standard gem-diol dehydration to form a carbonyl (lose an H from the OH, O remains attached). Formic acid doesn't have a gem-diol, and forming CO from it would involve loss of H from the C itself. It's pretty difficult to envision losing H and OH from the same position and getting anything close to a stable structure in general: dehydrohalogenation from a single atom (R₂C(H)(X)→R₂C analogous to your O=C(H)(OH) proposal) gives a carbene, which is generally extremely unstable unless there is something special about the R groups.

On the other hand, carbon monoxide is an anhydride of formic acid (see our formic anhydride article for details about CO formation in this sense). The carbene-like structure for O=C: in particular is just a resonance form of carbon monoxide, and the lone-pair on the "carbonyl oxygen" is exactly special to fix the octet instability of this carbene. DMacks (talk) 03:48, 13 May 2012 (UTC)

My conclusion stemmed from the fact that CO itself does not seem to hydrolyze in a reaction like CO(g) + H₂O(l)→ H₂CO₂ analogous to carbonic acid.--Jasper Deng (talk) 03:56, 13 May 2012 (UTC)

Carbon monoxide does react with water, just not in the way your intuition thinks it does. See Water gas shift reaction. --Jayron32 04:11, 13 May 2012 (UTC)

I knew about that particular one... I guess that there's little reason for my previous predicted reaction? -Jasper Deng (talk) 04:13, 13 May 2012 (UTC)

(edit conflict) Formic acid is the first of a homologous series known as the carboxylic acids, and those form dimeric anhydrides. If you look at formic acid like acetic acid and propionic acid, you'll see the pattern. The oxidation state of carbon in all three of those is the same, whereas in the carbonate ion, the electronics are quite different. Another way to think of formic acid as quite different than carbonic acid: formic acid has one of its hydrogens bonded directly to carbon, whereas all of the hydrogens in carbonic acid are oxygen bound. Any of these ways of thinking of it will lead you to the more correct conclusions than you reached. --Jayron32 03:50, 13 May 2012 (UTC)

Sorta the same reason that phosphorous acid is diprotic while phosphoric acid is triprotic, I guess...--Jasper Deng (talk) 03:56, 13 May 2012 (UTC)

Have you looked at carbonous acid and methanediol? Plasmic Physics (talk) 07:03, 13 May 2012 (UTC)

Formic acid was once made at a large scale by dissolving CO in hot NaOH solution under pressure. So you could consider it to have some anhydride properties (stoichiometrically) Staticd (talk) 12:17, 13 May 2012 (UTC)

Are there any traits (genetic traits) that are only inherited from one parent?(mom or dad)

Like the mitochondrial DNA that is inherited only from mothers?--2.147.67.209 (talk) 06:43, 13 May 2012 (UTC)

Anything on the Y chromosome is inherited from the father. Boys only, of course. — kwami (talk) 07:53, 13 May 2012 (UTC)

Colour-blindness in boys comes via the mothers. There are others, but I can't remember them right now. HiLo48 (talk) 08:29, 13 May 2012 (UTC)

Yes, the mitochondrial DNA is only inherited from the mother. Since virtually everything inside that DNA is directly related to the function of mitochondria, you don't really see anything but diseases being passed in it (i.e. when it works, you don't notice, except that you're not sick/dead). See Mitochondrial disease for a list of potentially inherited traits. As mentioned above, the Y chromosome is only inherited from the father. Explaining what HiLo said, boys inherit their X chromosome only from their mother. Sex linkage lists a variety of diseases that are linked to the X chromosome. There is also the case of genomic imprinting, in which case you inherit the DNA from both parents, but the DNA from only one parent is active and determines the phenotype. There are maybe 90 such genes, spread out across the chromosomes. Someguy1221 (talk) 08:46, 13 May 2012 (UTC)

Greenland as three islands

There's been a problem with an unref'd or poorly ref'd assertion at Greenland for several years now. The common understanding is that Greenland is really three islands connected by ice. A look at a topographic map shows that's not true: the center is below sea level, but the rim is unbroken. However, AFAIK that's not where the story came from. If the ice sheet were to melt completely, the sea level would rise 6–7 m, and then Greenland would be three islands; conversely, it's thought that glaciation united what had been three islands (at a higher sea level than now). I can't find a decent ref, though. Does anyone know of one, or am I remembering it wrong? (I can find lots of maps of what Florida would look like if the Greenland icecap were to melt, just not what Greenland would look like.) — kwami (talk) 07:52, 13 May 2012 (UTC)

Another theory is that as the icecaps melt, the weight removed would allow the land to rise, so none of Greenland without icecap may be below sea level. HiLo48 (talk) 08:27, 13 May 2012 (UTC)

Not a "theory" but a well-known phenomenon. It's pretty slow, though. Short Brigade Harvester Boris (talk) 21:24, 13 May 2012 (UTC)

I traced the assertion back to 1951 - see the reference I added to the article. However, the original discoverers said nothing about sea level rise so I deleted that bit. --Heron (talk) 09:56, 13 May 2012 (UTC)

check out greenland geology map186.151.67.249 (talk) 11:18, 13 May 2012 (UTC)

OK, you write the article and then we'll check it out. -- ♬ Jack of Oz ♬ ^{[your turn]} 21:39, 13 May 2012 (UTC)

Canada & the northern US are still rebounding from the retreat of the glaciers 11 ka, so I think it might be a while before the same happens to Greenland.

Without a rise in sea level, it looks as though Greenland would be a single island with a giant lake in the middle. But that's not realistic: all that water has to go somewhere. The 1951 claim may not have addressed that, but it's been done since. — kwami (talk) 03:01, 14 May 2012 (UTC)

And to further complicate matters, consider that the warmer conditions needed to melt the Greenland ice cap would also melt the ice shelves off Antarctica, some mainland Antarctic glaciers, and some other smaller glaciers. So, should that extra sea level rise also be taken into account ? If so, perhaps Greenland would be fully submerged. StuRat (talk) 04:51, 14 May 2012 (UTC)

No, that would not happen even if the entire planet were ice-free. But correlations with Antarctica are speculative, and you could at least hypothesize that only the northern hemisphere would be affected, as a minimal model. Not likely, but if Greenland melts, the sea level must rise by at least the amount of melt water from Greenland, so that's the theoretical lower bound. — kwami (talk) 11:09, 14 May 2012 (UTC)

I have a hard time imagining and scenario where only the Northern Hemisphere warms up. StuRat (talk) 23:33, 14 May 2012 (UTC)

Some kind of giant hat, perhaps? FiggyBee (talk) 13:27, 15 May 2012 (UTC)

I suppose if Greenland drifted south that might have the same effect, although the tens of millions of years for this to happen by continental drift is vastly longer than the glaciation cycles, which are on the order of tens of thousands of years. StuRat (talk) 17:02, 15 May 2012 (UTC)

The Nature of Jupiter's Metallic Hydrogen Interior

The wikipedia article of Jupiter says that most of the interior is Metallic hydrogen a kind of degenerate matter. What I'm not clear on is how solid this state of matter would be. Does the metallic hydrogen act more like a liquid or a solid or a gas? Ignoring the gravitational effects, could a spaceship fly through it? I've always been under the impression that Jupiter was mostly a cloud of gas and now need to revise my incorrect ideas. Thanks for any help. --CGPGrey (talk) 10:15, 13 May 2012 (UTC)

It says that in the Jupiter article that there is liquid metallic hydrogen; a spaceship cannot fly through the centre of Jupiter; it is not simply a cloud of gas. Plasmic Physics (talk) 10:31, 13 May 2012 (UTC)

It is a planet with a ferrosilicate core, with a mantle of liquid metallic hydrogen, overlaid with a deep ocean of super-critical molecular hydrogen, topped off with a thick atmosphere of various gasses. Plasmic Physics (talk) 10:45, 13 May 2012 (UTC)

To get hydrogen solid, it would need to be below the triple point temperature, which is only 13.84 K. Not very likely within a large planet. Keit120.145.7.207 (talk) 12:21, 13 May 2012 (UTC)

But as the pressure on the hydrogen increases, so does its melting point. Conceivably, the pressure inside Jupiter could be high enough for solid metallic hydrogen to exist near the core. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 12:40, 13 May 2012 (UTC)

The triple point is where all three phases can exist. Maybe you mean the critical point. But that's thepoint where there's no more difference betweengas and liquid. Higher pressure may still make it a solid. Ssscienccce (talk) 12:55, 13 May 2012 (UTC)

I meant the triple point. Whoop whoop could be correct if the melt line, which begins at the triple point, "leans" significantly towards higher temperatures at higher pressures. From memory, there's not a lot of lean in the hydrogen melt line, but I don't have a phase diagram for hydrogen to hand. Keit120.145.7.207 (talk) 14:21, 13 May 2012 (UTC)

There are some conflicting statements in the metalic hydrogen article imo:

• The initial prediction about the amount of pressure needed was eventually proven to be too low.
• Because previous predictions of the nature of those interiors had taken for granted metallization at a higher pressure than the one at which we now know it to happen, those predictions must now be adjusted.
• at 345 GPa, hydrogen is still not a true alkali metal
• at 140 GPa ... the hydrogen might be considered metallic.
• The lead mentions solid metallic hydrogen but the rest of the article seems to talk about liquid only. It's a bit confusing Ssscienccce (talk) 12:55, 13 May 2012 (UTC)

Even if it's a gas, that doesn't mean a spaceship could fly through it. The density would be enormous, which means the resistance would be enormous too. It would take lots of energy to move the spaceship and all that energy would go into generating heat, so the spaceship would either not move or it would burn up. --Tango (talk) 20:03, 13 May 2012 (UTC)

There is a possibility that metallic hydrogen could be metastable at low pressures. Then if a giant Jupiter like planet is destroyed in a collison, there could be small fragments containing metastable metallic hydrogen, which could give rise to strange meteorites, see here. Count Iblis (talk) 20:54, 13 May 2012 (UTC)

Interesting idea, what would happen if such a meteorite, composed of solid metallic hydrogen, entered Earth's atmosphere? Could it perhaps be a candidate for the Tunguska event? Plasmic Physics (talk) 00:43, 14 May 2012 (UTC)

Maybe a reson why it could descend so far into the atmosphere, could be that the hydrogen centre was thermally insulated by another frozen gas such carbon dioxide (not likely). Plasmic Physics (talk) 00:48, 14 May 2012 (UTC)

I don't think you can have metallic hydrogen at any temperature if the pressure is not something "astronomical" - and by that I mean more astronomical than a meteorite. ;) Besides, I think if you work it out you'll find a meteorite contains more energy in its motion than it would have in chemical energy even if it were hydrogen ... but I don't know for sure. Anyone up for an exercise? ;) Wnt (talk) 19:37, 15 May 2012 (UTC)

Stronger superacids than fluoroantimonic acid

Since gold pentafluoride and bismuth pentafluoride are both stronger fluoride-ion acceptors than antimony pentafluoride, shouldn't hexafluoroauric acid, HAuF₆, and hexafluorobismuthic acid, HBiF₆, be even stronger superacids than fluoroantimonic acid? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 12:15, 13 May 2012 (UTC)

I think these superacids are in the Brønsted–Lowry sense, so acidity is "how strongly does the metal–F complex hold the H" not "how strongly does the metal hold the F?". AuF₅ might be the strongest Lewis acid, since that deals with electron-acceptor modes of the metal center. But adding HF to AuF₅ causes the whole thing to decompose--due to that acidity--and liberate fluorine and gold(III) fluoride (see [[doi:10.1002/1521-3773(20011001)40:19<3690::AID-ANIE3690>3.0.CO;2-5]]) rather than forming a [AuF₆]^– cluster. I know this exact question has been asked on WP before but I can't find it right now. DMacks (talk) 15:47, 13 May 2012 (UTC)

Heh...was my talk-page. See User talk:DMacks/Archive 13#Need help from the smarter where I had found some refs and related ideas. DMacks (talk) 20:40, 13 May 2012 (UTC)

Steel laptop and electroshock

How do they isolate the steel of those new laptops so you don't get a shock? OsmanRF34 (talk) 12:51, 13 May 2012 (UTC)

I don't think there are any steel laptops, although some are made from aluminium or titanium alloys. They are isolated in the same way as any other electricity-using equipment with metal part (washing machines, cars, stereos, toasters...), namely by making sure that there is no electrical contact from power carrying circuits to the frame of the device. If you want more details, iFixit has an article on disassembling a unibody MacBook Pro with pictures showing how the components are mounted on plastic circuit boards mounted inside the metal unibody enclosure. --Stephan Schulz (talk) 13:42, 13 May 2012 (UTC)

In countries following European standards, and countries that have their own standards more or less in harmony with European standards, laptops and any other appliance mus conform to one or two choices. With Choice 1, any and all exposed meatl work must be electrically earthed. The 'third pin' (the one that is different to the other two, or is aligned different to the other two) on the power plug carries the earth connection. Should any fault occur which would otherwise make the exposed metal live, the current is carried away via the earth connection, so you can't get a shock. With Choice 2, the laptop or appliance must conform to the standard commonly known as "double insulated", and must display the double insulated symbol (two squares, one inside the other). In double insulated equipment, it is designed in such a way that no concievable fault can, on is own, cause the exposed metal work to become live. This may be achieved by simply providing two insulating barriers, or by other technically acceptable methods. Choice 1 is the most common choice for personal computers & laptops. As a general rule, countries that have only 2-pin wall outlets (eg Japan) historically had lower electrical standards. However, these days, as manufacturing is for world markets, equipment is made to conform to European standards. Keit120.145.7.207 (talk) 14:12, 13 May 2012 (UTC)

Further to the above valid replies, all the laptops that I have ever seen in the last fifteen years run from a low voltage (usually 19v) fed from a "power brick" (Switched-mode power supply) which conforms to the EU double-insulation standards in isolating the whole of the laptop from any high voltages. Dbfirs 15:08, 13 May 2012 (UTC)

I think Dbfirs' answer is actually the most relevant one here. It is the power adapter that will have to comply to the mains standard, not the laptop, the laptop runs on relatively low voltage DC. The metal on the laptop does not need to be earthed externally as it is not a shock hazard. Vespine (talk) 22:53, 13 May 2012 (UTC)

Not all laptops have external power units. All the laptops (Toshibas mostly) they issued us with at work had internal power supplies. Wickwack121.215.40.247 (talk) 00:42, 14 May 2012 (UTC)

Ah, I wondered if they existed. I was trying to remember whether my first work laptop (heavy and bought in the 1980s) had an internal supply. I assume they conform to the same double-insulation regulations, rather than have all metal earthed. Dbfirs 07:23, 14 May 2012 (UTC)

Nope. Those Toshiba laptops were earthed via the third pin, the same as a desktop PC. Wickwack60.230.232.194 (talk) 07:52, 14 May 2012 (UTC)

Was this perhaps a few years ago? I first looked at the available models at the Toshiba site, but had to expand my search a bit to find one: a Toshiba t5200 from 1988, 8.5 kg, with built-in power supply. Who would have thought that the first laptops didn't run on batteries... Ssscienccce (talk) 11:20, 14 May 2012 (UTC)

Promiscuity and inbreeding

Would a fully promiscuous mating system reduce the minimum starting population needed to avoid problems related to inbreeding? Assuming equal gender ratios in the starting population. Horselover Frost (talk · edits) 16:31, 13 May 2012 (UTC)

As compared to a monogamous mating system, I mean. Horselover Frost (talk · edits) 16:32, 13 May 2012 (UTC)

A fully promiscuous mating system would make the problem worse, not better, since it would imply some level of mating between close relatives. But if you didn't really mean that, then I think the answer is that it would not make any difference, since every child has precisely two parents regardless of how promiscuous the mating is. Looie496 (talk) 18:21, 13 May 2012 (UTC)

a system of non-random mate choice for dissimilar individuals would be the best defence against inbreeding in a small population. (rats can smell out close relatives and some plants reject closely related pollen from fertilizing their eggs). Here are my calculations for a random mate choice system -

• monogamy with random partner: If an individual has 'n' offspring, probability of all n being inbred = probability of picking a close relative (p)
• promiscous mating with random partners: probability of all n being inbred = probability of picking a close relative n times = pⁿ < p for n > 1.

So yes, by my rough calculations for a toy model promiscuity is better than monogamy for inbreeding.Staticd (talk) 19:09, 13 May 2012 (UTC)

What do you mean by "problems related to inbreeding", or "fully promiscuous"? There are many separate issues at play in inbreeding, and not all of them are necessarily detrimental to the population. In the meantime, you may be interested in founder effects, and assortative mating. SemanticMantis (talk) 19:51, 13 May 2012 (UTC)

Lead poisoning and weight gain

Could children's bodies react to lead poisoning with weight gain--to sequester the harmful lead in fat tissue?Rich (talk) 19:54, 13 May 2012 (UTC)

I doubt it, since the article mentions as classic signs and symptoms in children: loss of appetite, abdominal pain, vomiting, weight loss. Ssscienccce (talk) 21:35, 13 May 2012 (UTC)

What you're talking about is an evolutionary response. Those only occur in response to problems which remain a serious threat to the species for thousands of generations. Thus, we have evolved a starvation response to keep us alive during famines. However, toxic lead exposure is rare today, and almost unheard of throughout most of human history. That's just not enough of a threat to the species to cause such an evolutionary response. StuRat (talk) 04:57, 14 May 2012 (UTC)

Stu, if by "toxic lead exposure", you mean exposure high enough to produce obvious symptoms, then its true that such exposure isn't common. However, lead is toxic, meaning degradation in rational behavior and measurable degradation in intelligence, down to very low levels. In response to another question, somebody posted a link to a study that showed that blood levels in US children had dropped in recent years. However, in western countries generally, lead is ubiquitous in the environment, resulting in blood levels around 30 to 100 ug/L. The USA has set an arbitary limit of 100 ug/L as safe, but that is not universally accepted - some experts think that is too high. Even so, a significant fraction of childen are above the US limit. It only takes a few industrial incidents or lead-using industry not complying with requirments, or some developer turning old industrial estates into residential, and you get children way over 100 ug/L. Here in Australia, lead poisoning of children gets reported in the media from time to time. See example report http://www.esperanceport.com.au/downloads/inquiry/Leadissueupdate2.pdf Wickwack124.178.138.77 (talk) 05:55, 14 May 2012 (UTC)

But evolution doesn't care about low-level exposure (please, no comments on my anthropomorphization of evolution). It would only care if a large percentage of people were prevented from reproduction, due to lead exposure. StuRat (talk) 23:30, 14 May 2012 (UTC)

Correct. Low level exposure to lead reduces your intelligence, but it doesn't take much brains to get a girl pregnant. Wickwack120.145.187.143 (talk) 01:02, 15 May 2012 (UTC)

I dunno about "toxic lead exposure is [...] almost unheard of throughout most of human history". Lead has a long history of all kinds of uses in western civilization, and it has been suggested (controversially) that sapa made in lead pots was a contributing factor in the decline of the Roman empire. Better documented, back to ancient Greece, is illness among miners, plumbers and potters who worked with lead. In the medieval and early modern period there were frequent outbreaks of illness caused by alcoholic drinks made with lead equipment or sweetened with lead (Devon colic). Of course, I agree with the rest of your assessment. :) FiggyBee (talk) 22:47, 14 May 2012 (UTC)

thd

what total harmonic analyzer measures? — Preceding unsigned comment added by Vivekmishra1988 (talk • contribs) 20:05, 13 May 2012 (UTC)

Total harmonic distortion. Tevildo (talk) 20:12, 13 May 2012 (UTC)

And THD analyzer. Red Act (talk) 20:17, 13 May 2012 (UTC)

How does myopia work?

I'm wondering how shortsightedness can work: apparently it is usually due to the eyeball being too long, but the point as I see it is that the lens focuses the image so that it will land on the retina. I can't see why we treat it as a focal-length mismatch between the eye and the lens, when the lens is adjustable. It does not have a fixed focal length, so what is the problem? Why can't it just compensate?

Another question: why do people's eyes so frequently get worse? Why don't they spontaneously get better? Assuming the eye is fixed in size and shape from one's early years, what is actually changing to make shortsightedness worsen, and why does it not improve? Thanks in advance, IBE (talk) 20:24, 13 May 2012 (UTC)

It does compensate, which is why they can still see things that are nearby. There is a limit to the range of focal lengths the lens can produce, though. Normally, that limit allows objects at distances from a few centimetres to infinity to be in focus. For shortsighted people, the range doesn't go all the way to infinity. For longsighted people, it starts further away. Some people (particularly the elderly) have both, so end up with a very short range - this can be corrected with bifocals. --Tango (talk) 20:45, 13 May 2012 (UTC)

The lens and the cornea, in combination, focus the light to a particular point. If you have normal vision, the image lands in the right place on the retina. If the eyeball is slightly misshapen, the focused image does not land in the right place. As Tango says, your eyes can adjust, but only so much - and their ability to adjust decreases with age. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:10, 13 May 2012 (UTC)

I think the reason why eyes get worse with age is that our ability to change the focus decreases, as a normal part of aging. There is sometimes an improvement in vision, such as in middle age, when people tend to go from having myopia to presbyopia. This can result in a short window when vision is improved. Eye exercises might also improve vision, at least temporarily. StuRat (talk) 05:04, 14 May 2012 (UTC)

Presbyopia unfortunately cannot help myopia: myopia occurs when the longest focal length is too short (principally a function of the cornea and eye length), and presbyopia is the lengthening of the shortest focal length without affecting the longest (because it is the ability of the crystalline lens to shorten the focal length of the cornea that is reduced). Put differently, presbyopia reduces a sort of depth of field of the eye, rendering some distances impossible to focus on without granting any other focusable distances in exchange. --Tardis (talk) 01:22, 16 May 2012 (UTC)

Myopia may be caused partly by doing to much near work, or for example children that read a lot and keep the book close to their face. The ciliary muscle is a ring of smooth muscle around the lens. When the muscle s relaxed, the lens is stretched (flattened) by the zonule fibers that connect to the ciliary muscle. When the muscle contracts, the ring gets smaller, there's less stretching so the lens becomes more spherical. How this would explain myopia is not certain, it seems there are several theories. Some researchers suggest myopic people use reading glasses (+ dioptry) for near work. Now the opposite usually happens, children get perscription glasses when they can't read the blackboard in class, and they keep them on when reading and writing. To focus correctly, the ciliary muscle will have to contract even more in that situation. But we don't know for sure. It's not clear why myopia doesn't worsen as rapidly with contact lenses as with glasses for example. Ssscienccce (talk) 12:29, 14 May 2012 (UTC)

what is cally disease

got it off of a mate and has same symtoms — Preceding unsigned comment added by Errrrrrcally (talk • contribs) 20:54, 13 May 2012 (UTC)

See a doctor. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:04, 13 May 2012 (UTC)

Cally disease is a disease from the planet Auron, in the TV fiction Blake's 7. Has someone pulled your leg or are you pulling ours? Wickwack121.215.40.247 (talk) 00:37, 14 May 2012 (UTC)

Maybe that's what his unstated symptom is: A pulled leg. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:22, 14 May 2012 (UTC)

May 14

Why is KCN basic but not KNO3?

KCN is basic because $CN^{-}+H_{2}O\leftrightharpoons HCN+OH^{-}$. Why doesn't this happen for KNO3? $NO_{3}^{-}+H_{2}O\leftrightharpoons HNO_{3}+OH^{-}$ ? --130.56.90.101 (talk) 01:06, 14 May 2012 (UTC)

Because HNO₃ is a strong acid, which means that the NO₃^- ion will not take an H⁺ from water. HCN is a weak acid, which by definitions means that CN^- will take H⁺ from water. The reasoning is the strength of the relative bonds. In this case, the H-O bond in HNO₃ is much weaker than the H-O bond in water, so there is no impetus for the H⁺ to leave water and join with the NO₃^- ion. With the cyanide ion, the H-C bond in HCN is considerably stronger than the H-O bond in water, so the transfer is exothermic, and the water readily gives up its hydrogen to the cyanide. --Jayron32 01:16, 14 May 2012 (UTC)

Are the injuries sustained by Tony Stark at all possible?

I'm re-watching Iron Man (2008 film), and shortly after the start Tony Stark is injured during a fire-fight and discovers when he wakes up that there are pieces of shrapnel stuck in his chest which are impossible to remove but which if unchecked will penetrate his heart killing him. It is mentioned by another character that this injury is not uncommon in 'his village', and hence he knows the solution is to rig an electromagnet onto Stark's chest to stop the shrapnel moving any further. Now the final part sounds to me like clear fantasy, and I doubt anyone could actually ever be saved from any known injury by sticking a large magnet on their chest. How about the rest though? Have people ever sustained chest injuries from shrapnel that haven't been killed immediately but have died later from the shrapnel finally reaching vital organs? And if not, is it a reasonably plausible injury to occur in the right circumstances? Or is the entire thing just a story to explain the premise, and has no basis in fact at all? Thanks in advance. 130.88.172.34 (talk) 02:01, 14 May 2012 (UTC)

Yes, people have been killed by delayed effects of shrapnel, but absolutely the last thing you would ever do with somebody with dangerous shrapnel inside them is to bring them into the vicinity of a strong magnet. Looie496 (talk) 02:12, 14 May 2012 (UTC)

I seem to recall a story of a US Civil War soldier, wounded near the heart. The doctors concluded that the shrapnel/bullet (I forget which) was best left in, as trying to remove it would likely be fatal. The soldier then lived out his life, and died, in old age. The autopsy showed that his aorta (or maybe vena cava), now weakened with old age, had been torn by the metal fragments. So, he was, in a sense, the last Civil War victim. StuRat (talk) 05:10, 14 May 2012 (UTC)

Interesting stuff, thanks both of you. 130.88.172.34 (talk) 09:40, 14 May 2012 (UTC)

You're welcome, may we mark this Q resolved ? StuRat (talk) 16:38, 15 May 2012 (UTC)

Weight loss question

According to Weight_loss#Intentional_weight_loss, "Weight loss occurs when an individual is in a state of negative thermodynamic flux: when the body is exerting more energy (i.e. in work and metabolism) than it is consuming (i.e. from food or other nutritional supplements), it will use stored reserves from fat or muscle, gradually leading to weight loss." The article does not make it clear exactly what stored reserve is used: fat or muscle? So in a state of negative thermodynamic flux, will a person loose fat or muscle? --NGC 2736 (talk) 04:07, 14 May 2012 (UTC)

Both. The object is to lose more fat than muscle, of course, and exercise helps with that. Also, that weight loss summary seems to neglect the possibility of retaining water. In that case, losing weight merely means losing water, which has nothing to do with "thermodynamic flux". StuRat (talk) 05:12, 14 May 2012 (UTC)

Thanks. I was searching the Wikipedia articles on this topic and just found Dieting#Fat_loss_versus_muscle_loss. It has an uncited claim "If the diet plan includes a daily caloric intake greater than the basal metabolic rate (BMR), the person will most likely lose fat. In contrast, if the person follows a diet that includes a lower caloric intake than the BMR, this person will lose fat but also a higher percentage of muscle." Although there is a citation tag there, just wondering whether it is true? --NGC 2736 (talk) 05:28, 14 May 2012 (UTC)

I think the logic there is that fat can only be converted to energy so fast, and if that doesn't provide enough energy, muscle will also be burnt. I don't see how the BMR rate is a magic dividing line, though. I would expect it to be more of a continuum, with muscle loss increasing as the rate of weight loss increases. Something else that can happen, of course, is that virtually all of the fat can be gone, say in starvation victims, in which case only muscle remains to burn.

Another factor is that, as you lose weight, less muscle is required to do normal activities. Less leg muscle mass is required to walk, less heart mass to pump less blood a shorter distance, etc. So, unless you increase your exercise rate to compensate, your body will naturally lose muscle mass, as we are designed to use the minimum amount of energy required, and excess muscles "waste energy". StuRat (talk) 05:34, 14 May 2012 (UTC)

Thanks for the explanation. It was helpful. --NGC 2736 (talk) 01:32, 15 May 2012 (UTC)

You're welcome. Can I mark this Q resolved ? StuRat (talk) 05:59, 15 May 2012 (UTC)

Thermodynamics of nuclear reactions

Do thermodynamic concepts like thermodynamic free energy apply to nuclear reactions analogously to the way they are applied to chemical reactions?--82.137.12.211 (talk) 11:14, 14 May 2012 (UTC)

If yes, how is the formalism adapted to nuclear reactions?--82.137.12.211 (talk) 11:21, 14 May 2012 (UTC)

Yes, provided there rate of nuclear reactions are fast enough to maintain thermal equilibrium. In the early universe, nuclear reactions were occuring at a fast enough rate to maintain thermal equilibrium between e.g. neutrons and protons. But as the universe expanded and cooled the reaction rate dropped, and the ratio between neutrons and protons became "frozen" at exp[(mp - mn)c^2/(k T)] where T is the temperature at that freezout time. The neutrons ended up in deuterium and helium. This ratio can be calculated quite accurately, and this leads to a prediction for the helium abundance in the universe consistent with observations. Count Iblis (talk) 16:27, 14 May 2012 (UTC)

Help identifying swallowtail

These used to grow on some citrus plants (lime/lemon/sweet lime/orange not sure what was planted) and on curry trees (Murraya koenigii) in Mangalore, coastal southern India. They look like Papilio_polytes but the wing pattern seems to be missing one white spot in the center. Once I have these Identified, I can rename the and describe the good ones (the pupa and prepupal larva) for further use in wikipedia.

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It doesn't look like all of our photos here have that white spot, if I understand what you're talking about - see File:Pandiyana_aristolochiae_polytes_helenus.png. In any case, this butterfly is subject to polyphenism between different forms, which means that there will be hybrid zones in which there are intermediate forms. Depending on the precise genetics, all sorts of funny things might turn up there. So the specifics become very important... it might help to get full text for PMID 20192689 . Your photo looks a lot like the stichius form - see [14] - though others called this in India have differing patterns [15][16][17][18]. Here's an illustration of the diversity in Vietnam. [19] And identifying mimetic butterflies from wing patterns can be chancy anyway! This might be the sort of thing where you have to be hardcore and base the ID on genitalia [20] - or, preferably, molecular genetics, which should give more certainty, and perhaps even some unexpected surprises. Wnt (talk) 07:20, 15 May 2012 (UTC)

Help Identifying another swallow tail

Found this pupa on a Caryota fish tail palm leaf in mangalore.

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Well, a swallow doesn't make a summer, nor a swallow tail a swallowtail. ;) Note that this butterfly has only four visible legs, with the others being, at least, much reduced. This, and also the general appearance of the wing veins, puts it in Nymphalidae, the brush-footed butterflies, not Papilionidae, the swallowtails. The same wing vein lengthened in the swallowtails can also be lengthened in daggerwings like this and this. Haven't figured out this one yet though... Wnt (talk) 17:04, 14 May 2012 (UTC) OK, I'm looking at Elymnias hypermnestra. It came up when I searched for "Caryota hostplants Nymphalidae". here's another image. I'm not sure this is the precise species, mind you, but I definitely smell a wumpus. Wnt (talk) 17:24, 14 May 2012 (UTC)

You might be better off asking at http://www.whatsthatbug.com/ SmartSE (talk) 17:25, 14 May 2012 (UTC)

Is it possible (however unlikely) for quantum fluctuations to violate conservation of energy?

Could a stable electron-positron pair just pop into existence out of nothing without annihilating afterwards? Goodbye Galaxy (talk) 14:51, 14 May 2012 (UTC)

Even if the entire Universe is the result of a random quantum fluctuation, the answer could still be no. As there seems to be just enough negative potential energy to cancel out all the rest. Hcobb (talk) 15:02, 14 May 2012 (UTC)

No. Energy (defined by the Hamiltonian) is always conserved in any quantum theory. -- BenRG (talk) 19:12, 14 May 2012 (UTC)

women

Why do women have titties all their lives when they only need them when they have a baby, and might not even have a baby for many years? Why couldn't they grow during pregnancy? — Preceding unsigned comment added by 95.26.220.146 (talk) 18:36, 14 May 2012 (UTC)

Well, they do grow during and after pregnancy, and they only "operate" during the period of nursing, that is the milk glands only produce milk during that time period. During the rest of a woman's adult life, the serve a more recreational purpose. --Jayron32 19:58, 14 May 2012 (UTC)

See also Secondary_sex_characteristic#In_humans. Basically, the processes involved start in utero, and there has been no strong selective pressure to change this state of affairs. Also, using the word "titties" in a science question makes you sound like a troll. SemanticMantis (talk) 20:03, 14 May 2012 (UTC)

Since I have found swimming with breasts quite a different experience to swimming without them (your bouyancy is very different, you can swim along on your front without using your arms while still keeping your face out of the water, etc), and given the Aquatic Ape Hypothesis, I have occasionally pondered whether this was a factor. But, even if true, I don't see how it could be shown conclusively in my lifetime. Short of a trip in the Tardis.... 86.161.213.137 (talk) 22:03, 14 May 2012 (UTC)

Men also have "titties", some more pronounced than others, and they have no practical application at any time. Bielle (talk) 20:02, 14 May 2012 (UTC)

Well, the nipples serve no purpose in men, but the fat, just like fat everywhere else, serves as a reserve energy source. StuRat (talk) 20:20, 14 May 2012 (UTC)

I'd beg to differ with you that nipples serve no purpose in men. They serve no milk in men, but are quite useful in other, more recreational, aspects of the human condition. --Jayron32 20:24, 14 May 2012 (UTC)

On an odder note, male lactation... ;) Wnt (talk) 20:32, 14 May 2012 (UTC)

Sexual selection is the primary reason for their permanance in human females. That human females have hidden ovulation and constant sexual display leads to conditions that ensure pregnancy in individuals that may have otherwise wished to avoid this biological process that might kill them when giving birth due to complications caused by the human infant's large cranium. Also human infants are dependant on parental care for a long time and prior to permanent human settlements it would have been routine for offspring to feed off mothers milk for several years until they became more independant and able to help with the foraging. SkyMachine ⁽⁺⁺⁾ 22:02, 14 May 2012 (UTC)

This guy from the Game of Thrones tv show has the most impressive man boobs I've seen for a while. Vespine (talk) 22:29, 14 May 2012 (UTC)

The evolutionary perspective is necessary here. Women's breasts are large because Homo sapiens is sexually dimorphic and sexual attractants play vital role in sexual selection. Breasts function as sexual attractants without which it will be difficult for women to find mates which is prerequisite for reproduction and continuation of the species. Read the followings:

• Hypothesis for the Evolution of Human Breasts and Buttocks
• Evolutionary Perspectives on Permanent Breast Enlargement in Human Females

If you are seriously interested in the evolutionary purpose of women's breasts, I'll suggest go through the book The Naked Woman by Desmond Morris. --NGC 2736 (talk) 00:52, 15 May 2012 (UTC)

Humans walk upright, which means falling over is possible and has the potential to damage the front of the chest in ways quite unlikely in mammals that walk on all fours - in fact it is very difficult to get a 4-legged animal to trip or fall over in any case. Also, in less advanced societies, fights amongst females may have occurred from time to time. Most of the volume of women's breasts is fat and not milk-producing tissue, even when lactating. This fat protects the milk producing tissue. There was evolutionary pressure to increase the amount of protecting fat - Before the invention of formula milk, damage, even minor bruising, to the milk producing tissue could mean the death of your baby - one you have now, and possibly one you have later. And of course breasts make girls attractive to boys. Wickwack120.145.187.143 (talk) 01:19, 15 May 2012 (UTC)

• Desmond Morris has some interesting ideas, but they are basically Just-so stories. I encourage anyone reading his works to put on their skeptical and critical hats! SemanticMantis (talk) 16:00, 15 May 2012 (UTC)

Attractive to boys ... girls, men and women, oh yes, and babies. Bielle (talk) 03:38, 15 May 2012 (UTC)

Another thing to remember is that birth control is not actually part of the standard design - evolution tends to keep women pregnant and children fighting for survival. I imagine that in some of our less enjoyable societies those breasts are still in near-constant use.

I should add that not only did Darwin pursue his well-known discussion of the reasons for male nipples in "The Descent of Man" - apparently even his grandfather had ideas about it. [21] Darwin wrote there that "Now if we suppose that during a former prolonged period male mammals aided the females in nursing their offspring, and that afterwards from some cause, as from a smaller number of young being produced, the males ceased giving this aid, disuse of the organs during maturity would lead to their becoming inactive; and from two well-known principles of inheritance this state of inactivity would probably be transmitted to the males at the corresponding age of maturity. But at all earlier ages these organs would be left unaffected, so that they would be equally well developed in the young of both sexes."^[22] It is curious to consider all of the ideas - sexual selection, "spandrels", modern-day male lactation - that he does not run through in this. Wnt (talk) 13:48, 15 May 2012 (UTC)

• "birth control is not actually part of the standard design - evolution tends to keep women pregnant" - Hmm. So what are you saying, feminism is in conflict with evolution? --NGC 2736 (talk) 14:02, 15 May 2012 (UTC)

Peace of any kind is in conflict with evolution, except as a short-term tactic, and indeed evolution is one of rape's most ardent supporters. Most of the development of human culture can be cast as a struggle between the loyalty of the human body and instinct to the genome and its propagation, versus the loyalty of the human mind and spirit to itself in all its incarnations as a new and fundamental force of nature. Wnt (talk) 15:34, 15 May 2012 (UTC)

Surely you've heard of evolution of altruism? It is also very shortsighted to say "evolution is one of rape's most ardent supporters." Evolution can act on social structures just fine (e.g. pair bonding), and offspring of rape may well be less likely to successfully procreate. SemanticMantis (talk) 16:00, 15 May 2012 (UTC)

Nevertheless, what possible explanation in evolutionary terms can there be for the occurrence of rape other than it must have reproductive advantages in some cases? - Lindert (talk) 16:38, 15 May 2012 (UTC)

? What possible explanation in evolutionary terms can there be for the occurence of men getting drunk and punching other people in the face, other than that it must have reproductive advantages in some cases? What about pedophilia? What about getting turned on by being hurt, or by hurting others? What about body dysmorphia? What about daring each other to do pointless dangerous things until you're seriously injured? What about abusing your children, even to the point of death? When you're talking about something carried out by less than 5% of the population, you can find all sorts of behaviours and tendencies that don't improve reproductive success. 86.161.213.137 (talk) 16:54, 15 May 2012 (UTC)

For many of the things you mention there are possible advantages, e.g. punching each other, daring to dangerous activities, hurting others etc. can kill weak individuals or eliminate competition. A pedophile may occasionally impregnate a girl other men are not interested in, thus outsmarting the competition. Otherwise, if these things are always detrimental and they continue to exist, that is a problem for evolution, because natural selection should cause detrimental traits to die out. Btw in some animal species rape is very common, or even the norm. Note that I am in no ways encouraging the aforementioned actions, morals should not be based on reproductive advantages. - Lindert (talk) 18:35, 15 May 2012 (UTC)

LOL, okay, I think you need to step out of the Just-so story realm. Seriously, look at your pedophilia thing. Do you really think that is going to give an advantage over just having sex with a grown partner, the small chance that the child will actually conceive, survive the pregnancy and childbirth, and the baby will be raised to successfully breed itself? There is a tendency among people who have learnt just enough evolutionary theory, but not quite enough, to attribute everything as 'just how evolution made it', exactly fit for purpose. But it is obvious that some aspects of humanity exist as aberrations, such as someone who seeks a doctor to sever their spinal cord because they feel they are 'supposed' to be wheelchair bound, or severe alcoholism, or someone who cannot control their anger and alienates other people, or a pedophile, or a rapist. It is true that more moderate versions of some of the traits that produce this aberrant behaviour can be advantageous: it is easy to see how someone being more aggressive about meeting their own needs, over the needs of others, and perhaps a desire to have more sex than normal, could be a successful strategy in some circumstances, especially if they have the ability to temper it as needed. And it is also easy to see how an extreme version of that trait might contribute to somebody deciding to rape little old ladies. But that is far and away from saying that rape itself is favoured by evolution. 86.161.213.137 (talk) 19:48, 15 May 2012 (UTC)

You misunderstand what I'm saying. I'm not saying that pedophilia or rape in general is advantageous. But in the case of someone who has no other options, i.e. no woman will take him, he's unable to compete in the struggle to reproduce, then as a desperate measure it is always better for the purpose of reproduction to resort to rape and/or pedophilia than to remain without a sexual partner. - Lindert (talk) 20:11, 15 May 2012 (UTC)

Not true. Lactation itself suppresses the menstrual cycle, making conception less likely. This means a breastfeeding mother is less likely to fall pregnant again. This is a form of natural birth control, with the evolutionary drive being that falling pregnant again so quickly is dangerous for the mother and child. This is natural birth control, which evolution favours. Births about a year apart tend to arise in cultures that do not view breastmilk as the best food for babies.

On top of that, when bodyfat falls below a certain percentage, the menstrual cycle stops. This is rare in modern developed countries except for in anorexics, athletes and models, but historically common. This is also a form of natural birth control, preventing conception when the mother is malnourished.

Your view of human nature red in tooth and claw sadly neglects that humans are intensely social creatures, who tend to naturally form societies. Forming societies, and raising their young within them, is one of the ways humans have historically survived and prospered.

Also, if rape were actually about anything like passing on genes, we would find that women of childbearing age were disproportionately targetted. In fact, we find the opposite: vulnerable women are disproportionately targetting, especially children and the elderly. The younger the rapist, the more likely they are to rape an old woman. It has nothing to do with passing on genes, and cannot be so excused. The actual strategy which has some success, is the serial cuckold, who has sex with willing women and then doesn't stay to raise the children. This allows for a greater initial quantity, but doesn't spend energy of ensuring the children survive and breed. This contrasts with the strategy of staying and investing time and energy is raising the children, which gives each child a better chance of survival and breeding, but risks raising someone else's child. Both strategies are clearly evolutionarily significant, as can be seen by studies that look at what male character women find most attractive at various times in their menstrual cycle. Note that neither strategy involves rape. Human societies tend to punish rape, even if they don't all agree on what counts. We evolved alongside our culture. 86.161.213.137 (talk) 16:10, 15 May 2012 (UTC)

Well, if you consider a situation like German camp brothels in World War II or Rape in the Bosnian War, rapists have no objection at all to women of the right age and characteristics for effective breeding. Wnt (talk) 19:33, 15 May 2012 (UTC)

Did I say they did? No, I said that the general pattern of rape does not suggest that it aims to increase offspring, since the general pattern of rape targets the vulnerable rather than the fertile. 86.161.213.137 (talk) 19:48, 15 May 2012 (UTC)

And that is simply a flawed argument. Just because the individuals targeted are no ideal opportunities for reproduction does not in the least imply that that is not the aim. Compare a lioness targeting mostly old, sick and young zebras. Does that mean the lioness does not aim for the best possible meal? A healthy adult zebra would provide much more food for the lioness and her family. It's just a matter of taking the easiest route instead of accepting a high risk of failure. The same goes for the rapist. - Lindert (talk) 11:48, 16 May 2012 (UTC)

Many primative cultures had birth control, some were very efficient. For example, initiation ceremonies of male Australian aborigines often involved cutting the penis so that almost all semen was discharged and not injected into the woman. When children were specifically desired, the fingers were used to close the hole and thereby cause all semen to be injected into the woman. They had been doing that for at least 40,000 years, long enough for other evolutionary pressures on breast size to act. But breast size in Australian aborigines is no different to that of Europeans. In some cultures, it is believed that women had their own secret methods. Also, evolution does not act to keep females pregnant. When times are tough and food scarce, too many children consume too many resources, and can actually reduce group survival. Wickwack124.182.184.54 (talk) 15:02, 15 May 2012 (UTC)

Sounds amazing. Is there a good source for that initiation story? HiLo48 (talk) 11:57, 16 May 2012 (UTC)

Oh my God, there are still weird things in the world of which I have no inkling. Penile subincision. While I had a vague appreciation that human genetic diversity shouldn't be shoehorned into a hierarchy by the judgmental, I had no concept that some cultures would actually view something akin to hypospadias as the normal/desirable condition. But interesting as that is, 40,000 years is not much time by evolutionary standards. Wnt (talk) 15:40, 15 May 2012 (UTC)

Will Mira B explode?

How close is Mira B to the Chandrasekhar limit? Hcobb (talk) 18:44, 14 May 2012 (UTC)

As the article you linked to says, Mira B appears to be a main sequence star, not a white dwarf, so the Chandrasekhar limit isn't relevant. --Tango (talk) 23:57, 14 May 2012 (UTC)

Wasn't every white dwarf formerly on the main sequence? —Tamfang (talk) 06:12, 15 May 2012 (UTC)

The article says recent measurements indicate it is a white dwarf of 0.7 solar mass, half the limit. —Tamfang (talk) 06:12, 15 May 2012 (UTC)

glass in soil

I purchased some soil from Home Depot to put on my garden. After I spread it on my garden I noticed when the light hits it it looks like it has little tiny pieces of broken glass in it. I'm assuming they added this for decorative reasons. Is this possible? I'm surprised the government would let them do that--Wrk678 (talk) 22:27, 14 May 2012 (UTC)

Probably not for decorative reasons, nor is it broken glass. A better bet would be the presence of small rock bits in your soil, which possibly may have been polished to that state by the amount of agitation its processing involves. It could also be a supplement material for certain required elements, like magnesium. Just musing.--Jasper Deng (talk) 22:31, 14 May 2012 (UTC)

I don't think so because it is clear--Wrk678 (talk) 23:03, 14 May 2012 (UTC)

Unless it's in shards, it's most likely just quartz sand. I doubt if it was added intentionally. StuRat (talk) 23:20, 14 May 2012 (UTC)

I've seen some batches of soil from those stores with bits that look a lot like mica. DMacks (talk) 00:44, 15 May 2012 (UTC)

Is it possible you're looking at vermiculite? (Which according to the article might actually be more disturbing....) Wnt (talk) 01:14, 15 May 2012 (UTC)

expanded vermiculite is used in soil. It's also the substrate of choice for growing magic mushrooms :-) Ssscienccce (talk) 11:45, 15 May 2012 (UTC)

whatever it is, I think it was added intentionally because I also found it in some cow manure fertilizer I purchased--Wrk678 (talk) 01:56, 15 May 2012 (UTC)

I believe that they add sand to improve drainage. StuRat's answer sounds likely to me (we're agreeing again!). Alansplodge (talk) 09:50, 15 May 2012 (UTC)

Mica and perlite are also common ingredients in soil mixes and soil additives. Mica especially can occur in clear, glassy flakes. SemanticMantis (talk) 11:11, 15 May 2012 (UTC)

It could well be glass. When glass recyclers round here get small fragments of glass they just crush them very small and mix it into potting mix. This is because it is too hard to separate the different colours when the glass is broken into small bits. Graeme Bartlett (talk) 13:03, 15 May 2012 (UTC)

May 15

Surfactants

Which have the best cleaning property : anionic surfactant, cationic surfactant or nonionic surfactant? — Preceding unsigned comment added by 113.162.202.31 (talk) 02:59, 15 May 2012 (UTC)

I guess that would depend on what you are trying to emulsify. I assume you know the difference between the three types? (I do.) Plasmic Physics (talk) 06:22, 15 May 2012 (UTC)

Proper Dimensions for Mortality Rates

Compare these two statements:

"XXXXX syndrome has a mortality rate of 8%."

and

"XXXXX syndrome has a mortality rate of 8% per annum."

Is it usual to express mortality rate per unit of time, e.g., "8% of people with this syndrome are likely to die within a year"

Or WITHOUT a dimension of time, e.g., "8% of people who develop this syndrome are likely to die from it eventually."

Thanks, Wanderer57 (talk) 04:19, 15 May 2012 (UTC)

Mortality rates for non-permanent conditions are often offered without a dimension of time. But if you actually dig into the literature used to cite the statement, you will always find time measurements or additional caveats buried in the methods of measurement, even they're not presented as part of the short conclusion. Someguy1221 (talk) 04:26, 15 May 2012 (UTC)

Agreed. For something like influenza, it's likely to either kill you, or not, in short order, while with a disease like diabetes, you might live with it for years before it finally kills you (or something else does). So, flu mortality doesn't need to be broken up by year, while diabetes does (although the total mortality rate from diabetes is also useful). StuRat (talk) 05:57, 15 May 2012 (UTC)

how much farther does a giraffe see

Hi,

how much farther does giraffe see? I mean due to vantage. --80.99.254.208 (talk) 10:59, 15 May 2012 (UTC)

The article Horizon contains various methods to calculate the distance, but first you need to measure your giraffe! Roger (talk) 11:16, 15 May 2012 (UTC)

Right, I just popped out and held down a giraffe long enough to measure it. Turns out they're between 5 & 6 metres tall. Assuming an average of 5.5m, using the calculation from the Horizon article we get a 'distance to the horizon' for the average giraffe of 8.37 km. That's 3.67 km further than the average human (4.37km at an average height of 1.7 m), a little less than twice as far. - Cucumber Mike (talk) 11:42, 15 May 2012 (UTC)

Wow, that's dramatic. Like, "If I have seen farther than those who came before me, then it is because I am a giraffe." — Preceding unsigned comment added by 188.6.70.25 (talk) 12:34, 15 May 2012 (UTC)

...or stood on the shoulders of the giraffes before you. :-) StuRat (talk) 16:22, 15 May 2012 (UTC)

Maybe it's giraffes all the way down. Gandalf61 (talk) 16:25, 15 May 2012 (UTC)

Note that this assumes a perfectly flat (actually spherical) surface with no trees or other objects in the way. And, since giraffes are that tall to reach leaves on even higher trees, we can assume that there frequently are trees blocking the view. StuRat (talk) 16:24, 15 May 2012 (UTC)

You also have to make an appointment for your giraffe to see an optometrist, because he might not actually be capable of seeing clearly all the way to the horizon anyway. Roger (talk) 16:30, 15 May 2012 (UTC)

Apparently giraffes do have excellent vision. As for the question, why do giraffes have long necks, the answer is that they have smelly feet. (*rolling tumbleweed* .... but my inner child is rolling in the aisles) FlowerpotmaN·(t) 16:56, 15 May 2012 (UTC)

You mean hooves. — Preceding unsigned comment added by 165.212.189.187 (talk) 14:02, 16 May 2012 (UTC)

Magnetic moment of a neutron

How does the quark structure of a neutron acount for its magnetic moment?--188.26.22.131 (talk) 11:35, 15 May 2012 (UTC)

There is a Neutron magnetic moment article, but unfortunately it's not much more than a stub. Red Act (talk) 19:21, 15 May 2012 (UTC)

The individual quarks within a neutron generate their own magnetic fields. And so the neutron will have its own magnetic field that is the superposition of the fields of its constituent quarks, resulting in a measurable magnetic moment even though it has no net charge. This is similar to how an electric dipole can have an electric field even though it need not have any net charge. And that's as much as I can tell you, for I don't know how to calculate magnetic fields/moments in quantum physics, much less how to superimpose the fields within a baryon. Someguy1221 (talk) 01:28, 16 May 2012 (UTC)

Lemonade (Citrus limon × reticulata)

How do I germinate lemonade seeds, what do I need to do to produce healthy seedlings? I have decided to use a paste made from crushed wheat biscuts mixed with water as a growth medium. The seeds have already been dried, naturally of course. Plasmic Physics (talk) 11:44, 15 May 2012 (UTC)

I found citrus seedlings are quite hardy when they are planted/germinated in sandy well drained loam (buried around 2cm deep). Once they grow a bit, they can be transplanted into their final destination. Will need the advice of someone better at horticulture for this though. (BTW, why are you trying to use that particular growth medium? I would expect that It to just help bacteria and fungi grow causing it to sour and form a film on the roots. Also I am not sure how much extra benefit the seeds would gain from the medium as the seeds are quite big. Again, just OR and speculation) Staticd (talk) 12:38, 15 May 2012 (UTC)

Staticd's instructions on medium and depth are good. I see that you are in the UK. It is probably not warm/ bright enough there right now to get fast results outdoors (e.g. not enough degree days), but it should work, given that you don't let it get moldy or drop below 40 F. If you are less patient, you could sprout it indoors, and provide supplemental lighting. It is important to not let it dry out, but also not to keep it sodden. "Evenly moist" is what you're going for. Lastly, your choice of medium does indeed seem bizarre, and likely to end in a moldy mess. Did someone suggest it to you, or did you read about it somewhere? Even if you don't want to buy peat pots, or potting soil, sandy loam is a far superior sprouting medium than crushed biscuits. Good luck! SemanticMantis (talk) 13:22, 15 May 2012 (UTC)

I'm actually posting from New Zealand, I live in a multistory appartment building; I'm growing it indoors for now. Thanks, I'll try and find some sandy loam. Plasmic Physics (talk) 15:00, 15 May 2012 (UTC)

Growth media are better suited for bacteria, fungi or cell cultures. Germination is what you wantSsscienccce (talk) 13:37, 15 May 2012 (UTC)

Is my idea then completely unsuitable, or will it just impede their development? Plasmic Physics (talk) 15:00, 15 May 2012 (UTC)

I feel that it will impede their growth quite dreadfully (going by my experience with pots having insufficient drainage and attempts at fermenting foods to get microscopy samples) so please don't try this unless you have a good source or you want to experiment. (Please do tell us the results if you do try it, I'm quite curious). Citrus plants need a lot of sun, but florescent light should do just fine. (They use them in the growth chambers at my research lab. Staticd (talk) 15:21, 15 May 2012 (UTC)

It contains a lot of nutrients your plant cannot use, but molds can. Plants mainly get water and inorganic nutrients from the soil. I doubt they can absorb carbohydrates, they get their carbon from CO2. A seed normally contains enough energy to grow the seed leaves, and then photosynthesis takes over. I'm not saying it's impossible to grow in such a medium but they have to compete against molds for which this is the perfect substrate, and there's lots of spores floating around. That's why substrate for growing mushrooms is sterilised in a pressure cooker first. Ssscienccce (talk) 17:17, 15 May 2012 (UTC)

It's amazing what mould can do. I remember saving bread end-crusts, before throwing them on the lawn when I get the chance. I forgot about a particular collection, and when I finally remembered, I found that mould had completely turned it into green dust. I made the mistake of opening the bag it used to be in, it sent a stiffling, noxious green cloud into the air. I also noticed that bread kept in a bag and chilled, and then returned to room temperature, will mould faster than a bagged bread kept at constant room temperature. I think it has to do with the reduced vapour pressure, which caused liquid water to condense on the bread. Plasmic Physics (talk) 03:01, 16 May 2012 (UTC)

Please send us photos when those lemonade seeds grow. I'd like to see what type of carton they sprout: Wax paper? Plastic? ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:45, 16 May 2012 (UTC)

I'm using a disposable plastic catering tray. Plasmic Physics (talk) 03:01, 16 May 2012 (UTC)

And another one bites the dust, eh Bugs? I liked it though. Richard Avery (talk) 07:25, 16 May 2012 (UTC)

Personal experience alert: about ten years ago, I managed to germinate three lemon seeds from a supermarket lemon by using a two-litre lemonade bottle. Cut it in half, fill about two-thirds of the bottom half with soil and/or compost (we have a fairly heavy clay soil where I live in the UK, but it didn't do any harm; I suspect sandy loam would be better), then plant your seeds in and wedge the top back on. Put it in a warm, sunny place for the seeds to germinate. If they need extra water, dribble some in through the top of the bottle. Eventually I planted mine in pots and kept them in a warm lean-to on the side of our house; they lived until they got too big to move around between summer and winter. Have fun, Brammers (talk/c) 10:08, 16 May 2012 (UTC)

Thanks.

Another question: are lemonades grown outside of australasia? Plasmic Physics (talk) 12:01, 16 May 2012 (UTC)

To be clear, "Citrus limon x reticulata" is one possible composition of the Meyer lemon. Is this the fruit being discussed here? And have some people in NZ started calling them "lemonades"? (Note as explained in the article, "Meyer" was the guy who introduced the original Chinese hybrid into the U.S., so I doubt our term applies there, at least) But this has a poster saying that lemonades are much sweeter than Meyer lemons. And this says limon x reticulata is more like a lime! NCBI delivers nothing of note about Meyer lemons, but Google Scholar yields a source talking about a Citrus meyerii[23] But ARS-GRIN calls lemonade a "hybrid of unknown parentage" [24] The joking above reflects that in the U.S. "lemonade" is strictly a drink and is never used to name a type of fruit. Clearly it would be much appreciated if some taxonomists would do a little molecular biology here! Wnt (talk) 15:28, 16 May 2012 (UTC)

Help identifying moths

Found this hawk moth/hornworm on some sort of colocasia.

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Found this pupa on a ficus(?) like shrub that grows wild around coastal India. A leaf is visible in the second pic. The moth never had any wings and I can tell that It was a female as it laid a whole lot of eggs a few days later.

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• 

Found this pupa on the same species as the previous moth.

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• 
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Thanks. Hope to make at least some of each set useful for articles once they have been Identified. Staticd (talk) 12:28, 15 May 2012 (UTC)

These appear to be the Theretra clotho [25], the wingless female Orgyia antiqua perhaps?, and the Glyphodes bivitralis.[26] (Disclaimer: I am not a lepidopterist! But I do like these bugs. :-))--Modocc (talk) 06:41, 16 May 2012 (UTC)

relationship between telomere length and cancer risk

Hello,

I am writing a biology paper on inhibiting telomerase to fight cancer, and I'd appreciate some help in interpreting the literature that's out there thus far. I'm not a biology student, but I did this research for a general education biology course at my college.

My literature review is focusing on this study published by Terry earlier this year, which stated that there is no clear relationship between telomere length and cancer risk. However, that seems to contradict the findings of Martinez-Delgado and others, who did find that shorter telomeres could present a risk factor for cancer. Indeed, my lit review has found that scientists have hoped to develop cancer therapies that focus on telomerase inhibition as a way to target malignant cells, and such methods rely on a strong association between telomere length and cancer risk. I know that it's not unusual for scientists to arrive at different conclusions, but what bothers me is that I can't find any articles online that attempt to reconcile these divergent findings. For example, I couldn't find any reactions to the Terry study, which seems to have overturned much of the previous literature. Am I looking at the wrong websites or databases, or am I approaching this paper in the wrong way? 128.135.100.102 (talk) 15:57, 15 May 2012 (UTC)

Not an answer, but have those considering such a treatment considered the side effects ? The telomere length is important for all cells, not just cancer cells, after all. While cancer cells reproduce more often, and thus will suffer from short telomeres sooner, all the cells in the body eventually will (except perhaps nerve cells which don't reproduce). StuRat (talk) 16:29, 15 May 2012 (UTC)

(aside to Stu:) Nerve cells do regenerate, in a few different ways. See Nerve_regeneration, Neuron#Nerve_regeneration, and Neurogenesis. The idea that they don't is just another incorrect "fact" they taught us in highschool ;) SemanticMantis (talk) 18:43, 15 May 2012 (UTC)

The lede in your first link says "...the central nervous system is, for the most part, incapable of self-repair and regeneration". StuRat (talk) 18:50, 15 May 2012 (UTC)

Sure it does. It then goes on to discuss a few different forms of regeneration that do occur. My last link says "Adult neurogenesis is an example of a long-held scientific theory being overturned." That's all I really wanted to point out. SemanticMantis (talk) 19:18, 15 May 2012 (UTC)

I was initially looking at the wrong study.. Anyway, the main or only difference I can see is that Martinez talks about age adjusted telomere length. The effect she found decreased with age, the highest OR was in women under 30. The ovarian cancer article gives a median age at diagnosis of 63, with 4.7% in women under 34. Maybe that explains part of the discrepancy, that the effect Martinez found would be smaller in Terry's study who grouped the subjects by telomere length instead of age? I believe some data could even support both conclusions, see Simpson's paradox. I also noticed that mutations in BRCA1 and BRCA2 genes were linked with an increased risk, and in the BRCA1 article there's a list of specific mutations depending on nationality; Is it possible that the relationship between telomere length and cancer risk would be related in some mutations, but not in others? Ssscienccce (talk) 19:30, 15 May 2012 (UTC)

The papers are just simply too new to have received any responses yet, I think. Note that the Martinez-Delgado paper cites the Terry paper. Looie496 (talk) 18:22, 15 May 2012 (UTC)

Even taking both papers at face value, they are not contradictory, as they deal with different cell types. A critical tumor suppressor in one tissue may be completely dispensable in another. Someguy1221 (talk) 19:07, 15 May 2012 (UTC) Sorry, I think I read the abstracts too fast. Someguy1221 (talk) 20:08, 15 May 2012 (UTC)

It looks like both consider correlations between peripheral blood leucocytes and ovarian cancer. As is too often the case, it looks like the smaller study had the significant (p<0.001) result, and the larger found no correlation. But I wouldn't want to simply discount the role of telomeres, because the larger study found that variation in TERT. We'd have to get the full papers, pick over every detail of who was chosen for each study, consider the second author's discussion very carefully ... and even then, this is the sort of thing that might have to be resolved over the phone, if at all. Some questions in my mind would be if they were able to control in any way for the effect of cigarette smoking, obesity and so forth [27] and if there were any technical differences in how the studies did it. The problem is, I doubt it's the shortening of the telomeres per se that will cause cancer; it's probably what happens when a short telomere is found, or when there's no telomere at all. So my gut feeling is that the length of the telomere is the distraction and those polymorphisms in TERT are closer to what you should be interested in. It seems conceivable to me that you could make a drug that would affect TERT and have no effect on telomere length at all, yet affect the risk of cancer e.g. by affecting cellular senescence mechanisms. Wnt (talk) 19:16, 15 May 2012 (UTC)
Here's a numeric example that would give opposite conclusions: 10 young women with short trlomere's: 8 of them have cancer (80%). with long telomeres 30 out of 40 have cancer (75%). The numbers for old women are: short telomers: 60/100 (60%) long: 15/30 (50%) For both groups long telomers give a lower percentage. If you take the totals: short telomers: 68/110 (61%) long telomers: 45/70 (68%). So Martinez would find that short telomers increase the risk for young (80% to 75%) and for old women (60% to 50%) , while Terry would conclude that short telomers decrease the risk (61% to 68%). Ssscienccce (talk) 20:21, 15 May 2012 (UTC)

Grasshopper in Zion National Park

Grasshopper in Zion National Park

I was looking for a page similar to de:Wikipedia:Redaktion Biologie/Bestimmung, but it seems that there is none. Anyway, I hope is the right place for my question.
I took a photo of a comely grasshopper and uploaded it to Commons. However, since neither me nor editors from de.wikipedia were able to identify the species, it is not very useful. I hope a biologist from the Southwestern United States may help.
Place: Zion National Park; time: August. --Leyo 21:23, 15 May 2012 (UTC)

I'm not a biologist, but it looks a lot like Melanoplus femurrubrum to me. Cf. this image, for instance. Deor (talk) 23:03, 15 May 2012 (UTC)

I'm no entomologist, or more specifically, I'm no orthopterologist, but that looks like a very good match to me. ;) Vespine (talk) 23:47, 15 May 2012 (UTC)

:-)

Deor, you seem to have hit the bull's eye. Thank you. --Leyo 07:32, 16 May 2012 (UTC)

Non-ethanol effects of alcoholic beverages

Can anyone find any information about why different alcoholic drinks have different effects independent of the volume of ethanol consumed? The effects of champagne, red wine, whisky, rum, gin and beer are all subtly different, yet I've never read anything to explain why. The volume of water has some effect with beer, but the hops have others; presumably the herbs used in gin make a difference too, as do the flavonoids in red wine. Are there are secondary metabolites that brewers yeast produces during fermentation that are bioactive in humans? SmartSE (talk) 01:00, 16 May 2012 (UTC)

Whilst we're at it, can anyone improve on the first sentence of Ethanol#Pharmacology? SmartSE (talk) 01:06, 16 May 2012 (UTC)

I'm guessing this is mostly observer bias. Someguy1221 (talk) 01:11, 16 May 2012 (UTC)

Someguy is probably close to the answer. There have been numerous studies which show that a large portion of drunkeness is psychological, and not directly related to the ethanol itself. I have seen countless studies and demonstrations which show the placebo effect on drunkenness; people who are given non-alcoholic beverages and told they are alcoholic show signs of intoxication. It is quite likely that different types of drinks make you feel certain ways, not for their chemical composition, but for the social implications of what they represent (champagne or fine wine feels sophisticated, big fruity drinks seem fun, etc. etc.) so your internal feelings likely represent something of that beyond the mere chemical effects of the drink. That's my guess, anyways. --Jayron32 01:47, 16 May 2012 (UTC)

There's a few other possible factors at play as well: Many people can have an adverse reaction to sulphites found in certain drinks, especially wine. Anecdotal evidence suggests that drinks high in sugar can result in a worse hangover, but I have yet to find a reliable source for this. Also, if you have had a bad experience with a certain liquor (as in, you end the evening worshiping the porcelain gods), it is more likely to make you feel ill in the future: see Taste aversion. -RunningOnBrains^(talk) 01:54, 16 May 2012 (UTC)

fusel oils are supposed to worsen hangovers. Staticd (talk) 07:15, 16 May 2012 (UTC)

Ripping someone a new one

In among all the -ostomies and -plasties and whatnot, there's got to be a medical term describing the forcible creation of a new asshole. What would it be? --Carnildo (talk) 01:56, 16 May 2012 (UTC)

Giving someone a new asshole is actually a necessary medical procedure following certain types of rectal cancer. I see various articles calling this "rectal reconstruction", but I haven't seen anyone apply a fancy name to it. Someguy1221 (talk) 02:02, 16 May 2012 (UTC)

Ok, that actually made me laugh... I guess if we take the lead from tracheotomy, it would make it a rectumotomy, not sure if that sounds quite right, maybe rectotomy might need someone with some latin skills to figure out the correct spelling.. This reminds me of defenestration, the technical word for throwing someone (or something) out a window. Vespine (talk) 02:51, 16 May 2012 (UTC)

Newborns also can have an imperforate anus, which, as you can imagine, needs to be fixed fairly quickly. StuRat (talk) 03:18, 16 May 2012 (UTC)

What about colostomy which is quite a common procedure for people with advanced colonic cancer where removal of the colon is necessary. The exit is usually placed on the lower left or right front abdomen for the obvious reason that anastomosing the colon to the anus is difficult and likely to give poor control. Richard Avery (talk) 07:17, 16 May 2012 (UTC)

As proctology is the branch of medicine dealing with the rectum and anus, would it be proctostomy? As an aside, the proctologist at my local hospital is Mr Shatwell. Prime example of nominative determinism. --TammyMoet (talk) 08:44, 16 May 2012 (UTC)

Wouldn't a proctostomy be the removal of a proctologist impacted in your nether regions ? StuRat (talk) 16:15, 16 May 2012 (UTC)

List of Self Limiting diseases?

I'm trying to find this list. It appears that wikipedia does not have such a category. Many definitions I've found will list a few, but so far I've got gastroenteritis, hepatits, the common cold, dyptheria, tonsillitis, llaryngitis. I imagine an exhaustive list would be huge, but can anyone find (or has seen) a list of the most common 20 or so? Vespine (talk) 02:43, 16 May 2012 (UTC)

I don't think many of those qualify as "self-limiting" as they are limited by our immune response. A truly self-limiting organism would control it's own population, say with waste which is toxic to itself in sufficient quantities. StuRat (talk) 03:13, 16 May 2012 (UTC)

Self limiting in medicine has a slightly diffent meaning to that of general biology. From the article: the term may imply that the condition would run its course without the need of external influence, especially any medical treatment. Vespine (talk) 04:16, 16 May 2012 (UTC)

Don't all diseases run their course with or without medical treatment? 112.215.36.183 (talk) 10:16, 16 May 2012 (UTC)

If you count "death" as an allowable outcome, then yes. I presume, however, the OP is asking about diseases that don't normally result in death if left untreated. If that is the case, then I'd remove diphtheria from that list. --TammyMoet (talk) 11:06, 16 May 2012 (UTC)

If you search wikipedia for articles containing self limiting, you get 2464 results. The description usually has enough info to know if it is a self-limiting disease. Examples: Scheuermann's disease, Scleredema, Vernal keratoconjunctivitis, Transient synovitis, Epiploic appendagitis, idiopathic scoliosis, Mondor's disease, Acute posterior multifocal placoid pigment epitheliopathy, Pityriasis alba, Cricopharyngeal spasm, Necrotizing sialometaplasia... For a list of the most common ones, I guess the best way would be taking a list of the say 50 most common diseases and check which ones are self-limiting. Problem is finding such a list, I can't even find two sources that agree on the nr 1 (gum disease according to one tabloid), even found a list that had sociopathic personality disorder in the top five. Ssscienccce (talk) 16:55, 16 May 2012 (UTC)

red giant's maximum diameter

How big is red giant at the maximum diameter. Can some red giant be as big as Mars orbit. How we know how big will our red giant be? Does some red giant get as big as 2 AU or as big as 3 AU? What is the size range of red giant from the smallest to the biggest?--69.228.133.188 (talk) 02:44, 16 May 2012 (UTC)

Does red giant answer any of this ? Note that the "size" is usually given as mass, which tends to be fairly constant, versus volume or radius, which can change dramatically. They list 0.5 Suns to 10 Suns as the range, with any stars more massive than that called red supergiants. (The illustration in that last article answers your Mars question.) As for how they know what the Sun will do, that's based on it's mass. StuRat (talk) 03:02, 16 May 2012 (UTC)

If your question was specifically "What is the biggest star?", see VY Canis Majoris. Its radius is estimated to be between 8.4 and 9.8 astronomical units, which is almost out to the orbit of Saturn. You may also be interested in our List of largest known stars. As far as our sun, it is estimated its radius will only be about 1.2 AU at its maximum, so the Earth will likely escape destruction due to its increased orbital radius by then (not that any of us will be around to care). -RunningOnBrains^(talk) 03:26, 16 May 2012 (UTC)

1.2AU isn't the maximum, it continues to say that it will eventually grow to 2AU. Vespine (talk) 04:14, 16 May 2012 (UTC)

My question was the biggest red giant in size, not the red supergiant or biggest star. I am asking for largest red giant only.--69.228.133.188 (talk) 05:34, 16 May 2012 (UTC)

Well then the answer is about 200 solar radii (2AU); the cutoff between red giant and red supergiant is quite fuzzy, if not arbitrary. For instance, Epsilon Aurigae at 135 solar radii is described as a red supergiant, while Rho Persei at 164 solar radii is considered merely a Asymptotic giant branch star (i.e., red giant).RunningOnBrains^(talk) 05:50, 16 May 2012 (UTC)

An inquiry into the nature of solenoids

The equation $B_{z}={\frac {\mu _{0}}{4\pi }}{\frac {2\pi IN}{L}}\left[{\frac {d+L/2}{\sqrt {(d+L/2)^{2}+R^{2}}}}-{\frac {d-L/2}{\sqrt {(d-L/2)^{2}+R^{2}}}}\right]$ gives the axial magnetic field strength $B_{z}$ in a solenoid. This is true for the case where every turn of conductor in the solenoid has the same radius $R$. Would you expect the magnetic field strength measured in a coil consisting of many layers of turns, each with a slightly different radius, to be higher or lower in magnitude than that predicted by this equation using the inner radius of the solenoid? --130.56.84.118 (talk) 02:53, 16 May 2012 (UTC)

Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our policy here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. Anonymous.translator (talk) 03:23, 16 May 2012 (UTC)

GRRROOOAAAANANNNN. My line of reasoning was that the answer is higher because the many layers reinforce each other. Is this right? --150.203.114.37 (talk) 03:42, 16 May 2012 (UTC)

We actually can't answer your question because you didn't tell us enough about the multi-layered solenoid. Are you taking a solenoid with the same number of turns and simply altering the radii of the turns? Are you wrapping an additional solenoid around the original? Are you scrunching the solenoid up so that it's shorter and fatter? What is the distribution of radii with respect to the original radius? If you make the total circuit length longer, are you changing the total voltage to keep the current constant, or are you dropping the current to keep the total power output constant? Someguy1221 (talk) 04:08, 16 May 2012 (UTC)

I don't suspect this is a homework question, as it is more a test of algebra skills than magnetic understanding, and a generic math teacher is not likely to set such an applied question. On the other hand, electronics technicians and radio hams often ask this - they tend to only find the single layer formula in books etc.

Assuming you want to know what happens if you have the same total number of turns in a multilayer solenoid as in a single layer solenoid, with the current, wire gauge, and everything else the same, for comparison, the asnwer is simple: Apply the formula to each layer separately. The total axial field strength is the sum of the fields contributed by each layer. As the layer radius is lower (denominator) terms in the calculation, the layers are progressively less effective moving out from the inner layer. Therefore the total axial field strength in a multi-layer solenoid is less than that for a single layer coil of the same turns, and less than that estimated by taking the inner layer radius. However, if wire gauge is reduced so that the radial distance occupied by the turns is the same, you'll get near enough the same field. This is because the improved contribution of the inner layers is balanced by the reduced contribution of the outer layers. Keit120.145.9.168 (talk) —Preceding undated comment added 04:40, 16 May 2012 (UTC).

There seems to be some laziness in presenting an equation which contains 2 pi in the numerator and 4 pi in the denominator. Please simplify and ask again. Is it correct to infer that mu nought is the permeability of free space, I is current in amperes, and L is inductance in ohms? Is R in meters or centimeters? (My education included physics textbooks using both units of distance). Edison (talk) 05:34, 16 May 2012 (UTC)

You made me look at his formula again. It doesn't look right - for a start the Ln (natural log) symbol is missing. However, L in this case is not inductance (& inductance is not measured in ohms), but the length of the coil. Keit124.178.152.203 (talk) 07:18, 16 May 2012 (UTC)

Looks right to me, L being the length, and d the distance from the center (between -L/2 and L/2). If I understand the question correctly, it's whether using this formula for a multilayer solenoid, with R equal to the inner radius, would underestimate or overestimate the field strength? Assuming we're still talking about a solenoid of length L with N turns, I'd say the measured field strength would be lower, since the real radius is larger. Ssscienccce (talk) 17:44, 16 May 2012 (UTC)

Orbital Chainsaw

The Orbital Chainsaw would consist of thousands of small "teeth" satellites in Low Earth orbit. Each such tooth would have a reasonable sized solid state laser that was powered by ultracaps that were then refilled by solar power during the 99% of the orbit when that tooth wasn't over a useful target.

Each tooth is only over a target area for a short period of time, so only needs enough power storage to cover lasing for that short period of time.

The Orbital Chainsaw would have a thousand and one uses. From laser propulsion for laser powered aircraft and satellite launches (to fill in more teeth satellites), to weapons uses such as shooting down hostile ICBMs or satellite launches and dealing with gatherings of terrorists or other dissidents.

So why hasn't this been implemented yet? (What exactly is the flaw in this brilliant (pun intended) scheme of global domination?) Hcobb (talk) 10:58, 16 May 2012 (UTC)

You would need literally millions of satellites. Not very practical. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 11:09, 16 May 2012 (UTC)

Expensive. Plasmic Physics (talk) 11:10, 16 May 2012 (UTC)

Very—it would require more money than the entire U.S. gross national product. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 11:12, 16 May 2012 (UTC)

I don't know about the number but I agree cost seems to be a big factor. Consider say the cost of Iridium satellite constellation (which only involves 66 active satellites) or Globalstar or Orbcomm involving communications satellites. For example if we take Iridium, scale up the cost for your fancy laser satellites, times it by 50 for your proposal involving thousands of satellites (with some discount for the large number) and you probably end up with something more then the entire Military budget of the United States. Also while probably not banned by the Outer Space Treaty, I think it's clear such an extreme Militarisation of space is unlikely to be popular. The Strategic Defense Initiative was rather unpopular, and considering the existing ability of the US to nuke the entire planet many times over, the advantages seem slim considering the cost and unpopularity of such a move, mutually assured destruction is generally considered to remain a powerful deterence to any large enemy. In terms of 'rogue states', the US already have their Missile Defense Agency allegedly for that purpose. And smart bombs and UAVs to deal with gatherings of people they don't like. I think many would question how achievable most of your stated goals are anyway (using them from satellite launches sounds like wishful thinking to me). Nil Einne (talk) 11:37, 16 May 2012 (UTC)

Just compare the cost of the system against what is spent on commercial jet airliner fuel every year and it pays for itself in no time.

As for the number needed, assuming a reach of 200 km, fewer than 5000 satellites are needed to cover the entire Earth. Hcobb (talk) 12:05, 16 May 2012 (UTC)

Unlikely. Assuming this implausible amount, you would require 6332.573979 satellites. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 12:13, 16 May 2012 (UTC)

Exactly who is going to pay to get them up there? Plasmic Physics (talk) 12:19, 16 May 2012 (UTC)

Yeah. It is much easier to get citizens to pay for things to move them places than it is to get anyone to pay for orbital weapons already racked with other problems. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 12:46, 16 May 2012 (UTC)

And capacitors to store power collected in one orbit (1 hour) would have to store megawatts of energy. These would be big and heavy. Graeme Bartlett (talk) 12:39, 16 May 2012 (UTC)

And that would give complete 100% global coverage at all times (die penguin scum!). A few dozen would be sufficient for satellite launches. (At which point the launch costs go way down.) Hcobb (talk) 12:22, 16 May 2012 (UTC)

"And that would give complete 100% global coverage at all times." Wrong. Because circles do not tesselate, you would need at least twice that number. And practically, you would need twice that, to provide redundancy and allow for failures. Which comes out to over 25,000 satellites. And a number of satellites this large would be extremely difficult to keep from occulting each other, colliding with each other, dragging each other out of orbit etc. Dyson sphere#Dyson swarm lists the problems with such a large swarm of satellites. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 12:33, 16 May 2012 (UTC)

They only have to worry about occulting each other if they block a significant fraction of the sunshine striking the Earth. Given a a few meter diameter satellite every hundred km, this isn't much of a problem. As for energy storage the satellite would only be in a position to fire for an average of 200 km (not the full diameter of 400 km, because passing directly overhead is rare) and since it is traveling at 7 km/s it only fires for half a minute. Given a solid state laser of 100 kw, this is only three megajoules of power storage or 30 kg of ultracaps. Hcobb (talk) 12:59, 16 May 2012 (UTC)

Were the satellites light enough to be significantly helped to orbit by each others' lasers, then whenever one of the satellites fired its laser, the recoil would be enough to throw it into a higher orbit, possibly causing it to tumble as well, and forcing EITHER the launch of a replacement satellite, in which case the satellites would be literally one-use-only, necessitating replacement whenever fired, which would VASTLY increase the costs, OR the expenditure of large amounts of fuel to bring it back down to its rightful orbit.

Also, for attacks on ground-based targets, atmospheric attenuation might be a problem for objects near the satellite's horizon.

Firing the laser against property of another nation would be an act of war. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 13:04, 16 May 2012 (UTC)

It is also doubtful whether another space-faring nation would allow the development of such a system without deploying its own laser-armed killer satellites. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 13:11, 16 May 2012 (UTC)

Because of the energy conversion issues, the Solar sail effect of the solar cells would be much greater than the laser recoil and almost, but not quite, vanishing small. It still makes a tiny bit of sense to be able to tilt the solar cell wings to (very very slowly) bleed off excess rotational momentum from the stabilization reaction wheels. One imagines that any country able to achieve Prompt Global Strike against any target on or near the Earth within one second of locating that target wouldn't care very much about what other countries thought about it. Hcobb (talk) 13:21, 16 May 2012 (UTC)

See my post above about enemy killer satellites. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 13:24, 16 May 2012 (UTC)

Also, the force exerted by the laser on another satellite would be exactly equal to the force exerted on the satellite firing its laser. Have you any knowledge of Newton's third law of motion or the law of conservation of momentum? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 13:30, 16 May 2012 (UTC)

See Space-based solar power. I'm afraid you're golfing pretty far into the woods this time. There are limits on how precisely you can focus a laser from orbit. And using light defeats much of the purpose of space-based power since it gets absorbed in the atmosphere anyway. And a geosynchronous array loses only 75 minutes of sunlight to the Earth's shadow twice a year. And the satellites can be useful for power generation without being military assets. Wnt (talk) 14:54, 16 May 2012 (UTC)

Compatibility (mechanics)

Can someone explain to me in ver simple terms what compatibility in mechanics is? I've read the article on Wikipedia & many books but they all confuse me. Thanks.Clover345 (talk) 13:50, 16 May 2012 (UTC)

It means that a certain kind of parts can be used with ("are compatible with") a certain device. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 13:54, 16 May 2012 (UTC)

Well, I've read the Wikipedia article http://en.wikipedia.org/wiki/Compatibility_(mechanics), and I'm none the wiser. But it has nothing whatever to do with what Whoop whoop said. The word "compatibility" is apparently used in the sense that certain conditions must be satisfied for the math theory of deforming/bending a solid by distributed force to be valid, such as not tearing. The article needs to be re-written, or at least a preamble added, in ordinary language, so us ordinary mortals can figure out what possible use it might be. The wiki article was written by some math nut who likes the sound of his own gibberish, and thinks that links to other math nut stuff means something. Wickwack120.145.133.138 (talk) 15:30, 16 May 2012 (UTC)

It's unusual to see an article entirely written by one editor, but no, it's not total gibberish. You might like to read our article on Finite strain theory first, but unless you are "into" tensors, that might not make much sense either. I agree that the lead needs to be written for non-specialist readers. Dbfirs 16:04, 16 May 2012 (UTC)

I think it has to do with: 1) the deformation must be continuous, ie a curve or surface must still be a curve or surface after the deformation, and 2) the formulas or matrix representing the distortion have more unknowns than there are independent variables, so you'll have additional constraints, which are the compatibility equations. Edit: just found the Continuum mechanics article. Ssscienccce (talk) 19:05, 16 May 2012 (UTC)

Whether I saw the moon.

I saw a thin white cresent, perhaps waxing, not far above the horizon, roughly in the east, from London at 9:00 this morning. Was it the moon? 82.31.133.165 (talk) 14:01, 16 May 2012 (UTC)

Very likely yes. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 14:06, 16 May 2012 (UTC)

The Moon is in its waning crescent phase right now, and would appear as a thin crescent near the eastern horizon (and not too far from the sun) in the mornings. Also, there just isn't anything else that looks like a crescent moon in the sky, really, ever. TenOfAllTrades(talk) 14:10, 16 May 2012 (UTC)

Actually, the crescent was indeed waning. I confused waxing and waning. Thanks. 82.31.133.165 (talk) 19:20, 16 May 2012 (UTC)

Controversy on Gravitational Singularities

If the universe had begun from a single point of zero volume and infinite density and mass, then why is the present universe so imperfect? — Preceding unsigned comment added by 205.178.233.168 (talk) 14:04, 16 May 2012 (UTC)

"Imperfect" in what way? If you mean the uneven (yet still highly homogeneous and isotropic) distribution of matter, our article on cosmological inflation gives credit to quantum fluctuations magnified to large scales during that period, and further references the galaxy formation and evolution and structure formation articles. — Lomn 14:15, 16 May 2012 (UTC)

So far as I know - correct me if I'm wrong - this "point" never really existed, not even in theory. To quote our article, "This singularity signals the breakdown of general relativity. How closely we can extrapolate towards the singularity is debated—certainly no closer than the end of the Planck epoch." Given how much stuff is said to have happened in the first second after the Big Bang - see Chronology of the universe - it is hard to think of any part of the process as "actually" being "instantaneous" in any meaningful sense. It is simply absurdly fast and absurdly small by our yardsticks - by the vibrations of cesium atoms, for example. But in the philosophical sense - the sense abused by some as described in Religious interpretations of the Big Bang theory - I think it would make more sense to view our universe as infinitely "old" (in the sense of a logarithmic time), but "receding to the horizon" as we look backward to ages where different properties of matter predominated. So there is no need to explain this contradiction - indeed, if we extrapolate from any time we can actually observe, the hypothetical first point, if it existed, would be an imperfect point. Wnt (talk) 14:44, 16 May 2012 (UTC)

Spontaneous symmetry breaking Hcobb (talk) 16:52, 16 May 2012 (UTC)

Beryllium barrier

What would be happened if beryllium-8 were a stable isotope? --84.61.181.19 (talk) 17:09, 16 May 2012 (UTC)

The entire universe would scream in horror. Looie496 (talk) 17:32, 16 May 2012 (UTC)

Big bang nucleosynthesis#Heavy elements briefly discusses one consequence. I'm not sure how much sense it makes to discuss this happening in isolation though - would it be possible to change physics in such a way that this isotope becomes stable, but nothing else is affected? 81.98.43.107 (talk) 18:00, 16 May 2012 (UTC)

If beryllium-8 were 10 eV lighter, it would be stable. --84.61.181.19 (talk) 19:20, 16 May 2012 (UTC)