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August 4

Spotting nocturnal animals at night

So, I recently put up a bird feeder in my yard. It is on ~7 foot pole with a birdhouse/feeder on top in which I put sunflower seeds. The birds love it. But during the night, something eats all the seeds. I put a squirrel guard on the pole, and have personally witnessed (during the day) that it does a good job of keeping squirrels out of ther feeder. So I'm a bit stumped as to what is eating all my birdseed overnight. I had previously heard that there was a certain color light (red, green, blue?) that nocturnal animals can't register, and will approach feeders even though it is illuminated. I would like to know what color light this is so I can put one in my yard. I really just want to sit on my porch and spot the culprit, and not have deal with expensive infrared lights, or motion-cameras. Any assistance would be appreciated. Quinn ^{❀ BEAUTIFUL DAY} 00:30, 4 August 2011 (UTC)

I should say that I already have an exterior light fixture in the yard, with a regular old "white" light, so I'm hoping I can just change the bulb to a different color. Quinn ^{❀ BEAUTIFUL DAY} 00:32, 4 August 2011 (UTC)

I'm pretty sure it's red. Have you just tried to 'catch them in the act'? I have exactly the same thing happen at my place and it's possums they aren't timid at all, they'll walk on our deck even when the lights are on and we're out there too with guests over. It won't be possums where you are, but maybe whatever it is isn't as shy as you think. Vespine (talk) 01:08, 4 August 2011 (UTC)

Not sure where you think I am, exactly, because possums are pretty common in central Mississippi. Regardless, I don't think it's possums for the very reason you stated; whatever it is, it is very sneaky...won't come out when I have the lights on. I wonder if it could it be some sort of bug (insect) eating the seeds? Quinn ^{❀ BEAUTIFUL DAY} 01:23, 4 August 2011 (UTC)

Aah, so you call them possums too, they're technically opossums, we have possums in Australia. Vespine (talk) 03:29, 4 August 2011 (UTC)

A bat? The Northern flying squirrel? Are you sure it isn't just the birds getting up earlier than you? AndyTheGrump (talk) 01:29, 4 August 2011 (UTC)

I'd vote for a bat, too, although they mostly eat insects, but I imagine some might go for bird seed. Just in case it is something on foot, perhaps a raccoon, I suggest spreading some sand at the base of the pole so you can look for tracks the next morning. StuRat (talk) 02:14, 4 August 2011 (UTC)

Chupacabra. Either that or the Southern flying squirrel. Chances are 50/50. μηδείς (talk) 02:04, 4 August 2011 (UTC)

Ooops, yes, wrong squirrel species. :( AndyTheGrump (talk) 02:08, 4 August 2011 (UTC)

A good little mystery. Is the pole smooth metal or climbable? How far from the pole is the nearest tree? Birds can gobble seeds vwery quickly. You have probably thought of all this.

As for color of light, in our neck of the woods they sell strobe lights for the purpose of discouraging wildlife from coming near. The idea is to place the light where the animal cannot approach without looking at it. If something is climbing your pole, a downward-pointing strobe on the pole might have an effect. Wanderer57 (talk) 02:17, 4 August 2011 (UTC)

BTW, how do you know it's not birds eating the seeds ? You said they are eaten at night, but are you always up right at dawn ? The proverbial "early bird" might very well be the "culprit". StuRat (talk) 02:22, 4 August 2011 (UTC)

Could be birds, I suppose. If so, that's fine. That's what the feeder is for. But I'll get up at night and check it, and one minute the feeder is full...an hour later it's completely empty. And it holds a lot of seed. Getting kind of expensive, really. I should clarify, I don't simply want to identify it...I want to figure out the best way to catch it in the act so I can "get rid of it" if you catch my drift. Quinn ^{❀ BEAUTIFUL DAY} 02:48, 4 August 2011 (UTC)

So, in a nutshell, my question is: Is there a good way to observe wildlife at night? And again, a FLIR camera is a bit out of my price range. Quinn ^{❀ BEAUTIFUL DAY} 02:53, 4 August 2011 (UTC)

At my house (southeastern Canada), raccoons empty out bird feeders regularly, and these are feeders that hold 4 kilos (+/-10 pounds) of sunflower seeds when full. Unlike your predators, though, 'coons are not afraid of lights, even if I turn the lights on as they are feeding. Only opening a door they can see will get them to amble off, and they return minutes after I go back indoors. We finally had to electrify a plate at the base of the pole. 'Coons are smart and they test it every month or so. (For those of you reading this from the U.K. or other European points, don't panic; the shock is very mild from North American voltages.) Bielle (talk) 03:17, 4 August 2011 (UTC)

Maybe the creature eating it couldn't care less whether it is day or night. Therefore empty it out before dark, if possible. Then try to observe it unobtrusively from a distance at frequent intervals during the day. If it is a nocturnal creature it may make an exception and come out during the day, if it has become habituated to finding food at your feeder. Bus stop (talk) 03:28, 4 August 2011 (UTC)

That might work. Though come to think of it, you could simply take the feeder indoors at night, and leave the whatever-it-is to find food elsewhere. After all, I don't suppose it realises it is a bird-feeder. It found a source of food, so it eats it. If you do succeed in whacking it over the head with a baseball bat or something, another one is likely to discover the source of food later (unless you have exterminated the last surviving 'whatever'), so killing it doesn't solve the problem. AndyTheGrump (talk) 03:39, 4 August 2011 (UTC)

I have had the experience with raccoons as Bielle, if there's food they are quite willing to come into lit areas. Is this a tube-style feeder or more of a platform feeder? It could simply be that crows or other larger birds gobbling it up. I once came home to find that a bear had figured out how to open my iron silo feeder, which is metal and cannot be opened while hung up on its hook. The bear appeared to have swatted it down and knocked it around until the lid came off. Now I hang it up where bears can't reach. Beeblebrox (talk) 04:06, 4 August 2011 (UTC)

Beeblebrox, if you have bears, then you shouldn't have bird feeders. If you manage to keep them out, then they will still be in your yard, hungry, and angry, which is a very bad combo. StuRat (talk) 05:28, 4 August 2011 (UTC)

For the record, I think Racoons would eat you if you fell asleep outdoors at night. They aren't particularly aggressive or vicious, just an annoying combination of smart and persistant and not giving a shit. My dad went for YEARS trying to devise novel systems to keep the racoons out of our trashcans, and every year the racoons would figure it out. If we could somehow convince racoons to put on snazzy suits and wear sunglasses, they'd make perfect superspies. If the OP lives in an area with racoons, I'd vote for that as the likely culprit. Where I grew up, racoons weren't spooked by anything. We'd stand on our back steps at night and try to scare them off by throwing sand and rocks at them. They'd just look at us like we were crazy and go back to looting our trashcans. --Jayron32 05:52, 4 August 2011 (UTC)

Um, the problem is the strange desire that only those observed taking advantage of charity deserve it. The feeder's motivation is far from selfless. Next he'll want commercial endorsements and signed releases. Charity is charity, and commercialism commercialism. μηδείς (talk) 05:29, 4 August 2011 (UTC)

• @StuRat: Don't worry, I am well aware of bear danger (now). I've moved since that incident, at my new place the feeder is 20+ feet off the ground and the neighborhood bear has never even tried to get at it. We don't put seed in it in the spring when they are super-hungry and tend to come to town and get into people's garbage or dog food. Beeblebrox (talk) 18:48, 4 August 2011 (UTC)

Good job, Beebles. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 11:51, 5 August 2011 (UTC)

OP again: Doubt anyone is still paying attention to this, but in case you're interested, it turned out to be squirrels. It is a platform feeder on a 7 ft. pole, and even though I have an squirrel guard (an upside down metal cone beneath the feeder), which seemed to keep them out during the day, I caught a couple of squirrels raiding it just before day break. One squirrel would put its hind legs on the pole, and reach up and grab the rim of the cone. The other squirrel would get on it's back, and reach up and rake all of the seed off the platform onto the ground. Then they'd feed. This amazes me for 3 reasons:

• It's pretty ingenious what they are doing.
• It requires cooperation, in which the one that could reach the feeder rakes the seeds on the ground for both of them, when it could just as well have jumped from the other squirrels back onto the feeder and had it all to himself.
• The don't do this during the day when I know they're watching. When I'm on my porch watching the feeder, the squirrels remain on the ground, and act like they can't get around the squirrel guard.

Anyway, I've decided to just put a cupfull of seed in at a time, and figure that the squirrels are just a fact of life. Thanks for the suggestions. Quinn ^{❀ BEAUTIFUL DAY} 01:10, 5 August 2011 (UTC)

Not just "a" fact of life. The fact of life. μηδείς (talk) 01:44, 5 August 2011 (UTC)

@Quinn: That's actually pretty awesome. Nature can be amazing quite often. Thanks for sharing! --Jayron32 03:10, 5 August 2011 (UTC)

Now I'm concerned that you've unintentionally created a lab for the development of super-intelligent squirrels who will soon rise and enslave the human race. :-) StuRat (talk) 03:46, 9 August 2011 (UTC)

Response to Creationwiki

What is talk.origins's response to Creationwiki's refutations of Index to Creationist Claims? What are its people's response? — Preceding unsigned comment added by 110.174.63.234 (talk) 02:12, 4 August 2011 (UTC)

This is the Wikipedia science reference desk. Is this a question about a science-based matter? AndyTheGrump (talk) 02:16, 4 August 2011 (UTC)

Well, I think this is a science-based matter. But I don't see the need for more responses -- if there are some, will there need to be a response to the response to the response to each talk.origins item, which is itself a response to a creationist claim? At some point one just has to rest one's case. Looie496 (talk) 02:59, 4 August 2011 (UTC)

This is a science matter but it isn't really something for RD/S. If you want talk.origins responses, look in the web archives and some usenet archives of talk.origins like Google Groups. This should be relatively easy. If you can't find any, this likely means none exists. You are welcome to start a thread on talk.origins, observing appropriate netiquette (both general usenet netiquette and the specific netiquette of that group), if you really want responses but consider what Looie497 has said before you get your hopes up. Note even if anyone here posts to talk.origins, they shouldn't be giving a response like they would on talk.origins. Bear in mind talk.origins is just a usenet group, and the talk.origins archive is primarily someone's archive of selected posts to the usenet group. There is no such thing as an 'official' talk.origins response and if anyone did want to response, it would ultimately only be the response of that person. 06:42, 4 August 2011 (UTC)

Edit: As I expected, a quick search easily found a response to creationwiki on the archive site here, basically saying what Looie496 said. There is also some mention of creationwiki in this discussion [1] although I don't know if it's something in their rebuttal to the index. Bear in mind the archive has had minimal updating since 2006.

On the other hand, many discussions on the actual usenet group show up in a simple search [2] (safe search off), some of them may relate to the rebuttal to the index.

Nil Einne (talk) 06:55, 4 August 2011 (UTC)

It may be worth mentioning that the talk.* hierarchy was created especially to house discussions that tend to go back and forth forever with nobody ever changing their minds. Along with talk.origins there's talk.abortion, talk.politics.mideast, etc. These groups have existed for decades, and every possible argument and counterargument has probably appeared there already; it's just a matter of finding it. -- BenRG (talk) 07:57, 4 August 2011 (UTC)

ABO/Rh retype

i got my medical check-up result,and was curious about the medical terminology.ABO :O — Preceding unsigned comment added by 173.2.212.31 (talk) 05:32, 4 August 2011 (UTC)

See blood type. StuRat (talk) 05:46, 4 August 2011 (UTC)

International space station

Do the space stations have the ability to transform electricity through any equipments to the earth? provide the answers as quickly as posible to my email if any — Preceding unsigned comment added by Ebysebastian (talk • contribs) 06:56, 4 August 2011 (UTC)

The ISS, and previous stations (Skylab, Mir, and the Salyuts) only generate a small amount of power, enough for their own use. People have suggested giant space power stations which beam power down to the earth - see space-based solar power. -- Finlay McWalter ☻ Talk 09:13, 4 August 2011 (UTC)

Agreed, they don't have the ability to transfer electricity to the earth. (Well, maybe a tiny amount, if they charged a battery there which returned to Earth with the Shuttle.) StuRat (talk) 22:05, 5 August 2011 (UTC)

humans on other planets

actually universe is huge...we born on earth .which is in milkyway galaxy and our star sun..how about the evidence of the aliens or living creatures on other galaxies ? they too have huge stars and some dwarf galaxies too...is there any evidence or any reports those things? — Preceding unsigned comment added by Pebel vsrk (talk • contribs) 09:05, 4 August 2011 (UTC)

No evidence yet - see SETI. You need to clarify whether you specifically mean "humans" or "any intelligent life form". Humans are definitely unique to Earth. Roger (talk) 09:25, 4 August 2011 (UTC)

You know that how? --Trovatore (talk) 09:49, 4 August 2011 (UTC)

From the Australian Bureau of Statistics, "Our best estimates indicate that roughly 100% of all people live here." HiLo48 (talk) 10:25, 4 August 2011 (UTC)

Doesn't seem to be in the ref given. Anyway you haven't indicated how they would know.

If the physical universe has infinitely many galaxies, which it well may, and if there is a fixed positive probability of humans in any given galaxy, then by analogy to the infinite monkey theorem there is a probability of 1 (which is not the same as certainty — see almost surely) that there are humans in some other galaxy. Of course the "fixed positive probability" bit is a bit of a materialist assumption; it is not a given that "human" is definable in terms of configuration of matter. --Trovatore (talk) 20:45, 4 August 2011 (UTC)

Using the same argument, there must be a planet with intelligent pink flying pigs, or anything else you can imagine, and one identical to Earth except that this question was never asked! Seriously, though, I would remove the positive requirement on Trovatore's probability and get an answer of zero, but that is just my opinion. Estimates are just not valid from our slight knowledge of the origin of life because they "beg the question", and the universe might still turn out to be finite but unbounded. Dbfirs 07:35, 5 August 2011 (UTC)

The universe could turn out to be finite, but it might not. As I understand it the evidence is pretty balanced at the moment. That is, the confidence interval for the curvature includes the value zero — the simplest models for nonpositive curvature are infinite, for positive curvature, finite. There are compact models with negative curvature but in my admittedly non-expert opinion they come across as forced (they're things like a solid dodecahedron with opposite faces identified).

Curious why you think the probability per galaxy should be zero? Remember that you have to get exactly zero (or at least, for any positive ε, only finitely many galaxies where the probability is greater than ε) to avoid the conclusion that it will almost surely happen somewhere if the universe is infinite. Just saying the probability is not greater than one in $10^{10^{1000000000000000000000000000}}$ isn't good enough. --Trovatore (talk) 08:39, 5 August 2011 (UTC)

Yes, I deliberately chose zero because of my opinion on the origin of life (but this is not the place to argue over opinion). The question also arises as to whether the theoretical existence of something (planets, intelligent life, pink flying pigs) at an infinite distance constitutes existence as we know it. I rather liked Andy's comment regarding the Drake Equation in an answer below. Dbfirs 12:02, 5 August 2011 (UTC)

See also our article on extraterrestrial life.--Shantavira|^{feed me} 09:29, 4 August 2011 (UTC)

The only origin I can think of that would have a probability of exactly zero is some sort of deliberate creation, where the creator declined to do it elsewhere. I actually do believe in God, so I won't rule that out; I'm just curious whether that is in fact what you meant. It's a little hard to understand why God would have made such a big universe to put people in only one tiny corner of it, though.

As for infinite distances, there are no infinite distances involved in the scenario I'm talking about. The universe itself would be infinite, but the distance between any two points would be finite. So even if the existence of something infinitely far away would not constitute "existence as we know it", whatever that means, that doesn't change anything. If you meant that existence just so far away that we can never find out about it is not existence, well, that seems dangerously close to the rather discredited notion of logical positivism. --Trovatore (talk) 19:13, 5 August 2011 (UTC)

Yes, that's my reason for believing the zero probability, but I did say that it was only my opinion, not something I would try to prove. On the topology of possible universes, you are no doubt more knowledgeable than I, but I struggle to imagine an infinite universe in which all distances are finite, unless you are thinking of a Multiverse. Perhaps the universe is stranger than I can imagine? Dbfirs 19:49, 5 August 2011 (UTC)

Simplify — think of the real line. The real line itself is infinite, but the distance between any two points on it is finite. --Trovatore (talk) 19:51, 5 August 2011 (UTC)

Yes, sorry, my brain obviously wasn't functioning properly when I wrote the above. Your simplification occurred to me, and I (metaphorically) kicked myself before I read your reply. I should have compared the question of other intelligent life with the well-known question "Are there seven consecutive sevens in the decimal expansion on pi?" since we know the infinite structure of the straight line and mathematical 3- or 4-D space (-time), but we don't know the infinite "pattern" of pi. Dbfirs 06:43, 6 August 2011 (UTC)

... continued to explain my thinking ... The distance of the seventh consecutive seven in the decimal expansion of pi from the decimal point (using a metric of one unit per decimal place) could well be infinite -- no-one knows. By analogy, the distance from us to the nearest planet with pink flying elephants (or pigs or whatever you imagine) could well be infinite -- no-one knows. It all depends on whether an infinite universe is truly random, and that, currently, is a matter of faith, not science. Dbfirs 21:52, 6 August 2011 (UTC)

Evidence: Wow! did someone reply to our call? Cuddlyable3 (talk) 12:12, 4 August 2011 (UTC)

Before anyone jumps on to analyzing the atmospheric dynamics of hypothetical planetary systems in the reception-zone of the positive and negative feedhorns of the "Wow!" signal, how about the far simpler analysis of the PSRR of the signal processing circuit? How about the bit error rate of the digital computer that processed it? How about a root locus stability analysis of the analog and digital signal filters? How about intermodulation introducing an out-of-band signal into the spectrum under study? Four spurious samples of low-resolution data, with a duration lasting less than one minute, which have never been reproduced, do not constitute evidence of anything. I have never actually seen the circuits for the Big Ear; but I have spent a good amount of time in the formal and informal study of radio signal processing; and I see interesting bursts of noise every day. In all cases, if I care to investigate the noise, it invariably comes down to one of these benign factors; in other words, the "extraterrestrial signal" is "terrestrial noise." Very often, radio-noise is due to distant lightning strikes; or your neighbor opening their refrigerator door, causing the compressor to turn on, surging a few amps through the shared AC power transformer. The magnitude of these electromagnetic signals is much larger than any signal ever received from Outer Space - and they are noise. If you're lucky, you might be able to pick up extraterrestrial noise. At that stage, you can analyze its properties, compare it to known physics, and usually, you can say "hey, neat! My goofy radio contraption successfully detected ... radio signals from a stray electron in the high atmosphere that got a little hotter than usual because of direct sunlight." And you can publish your results in Science or Nature. Or something. But, to conclude extraterrestrial intelligence from four spurious samples defies any sort of procedural study of the signal. The Wow! signal is noise. This conclusion is obvious. Thorough understanding of radio physics, or at least an elementary primer in basic signal processing, is a prerequisite to legitimate radio-SETI. It is incredibly frustrating when legitimate scientific analysis takes a back-seat to populist sensationalism. Such silly and unfounded claims discredit the entire SETI effort. Or, to rephrase: if you don't know what noise looks like, how can you claim to know what a signal looks like? Nimur (talk) 18:19, 4 August 2011 (UTC)

Nimur you misrepresent the analysis by Dr. Jerry R. Ehman Ph.D. as having "concluded extraterrestrial intelligence from four spurious samples" that you declare are obviously noise. Please read his report to understand better. You are wrong about the received signal duration. Proper evaluation of the Wow! signal involves estimating the probability of a terrestrial source or conceivable combination of sources causing an emission on a frequency that is globally protected for radio astronomy and which, during its detection, matched the scanning lobe shape of a receiving horn that I understood to be calibrated against point sources in space that are not in dispute. You parade a select few signal-to-noise limitations as though they are relevant to faulty design of circuits for the Big Ear that you have not seen! Some extraordinary evidence is needed to back your claims that 1) serious radio astronomy is pursued oblivious to lightning and refrigerator power surges, and 2) you know things about signal processing that were not common knowledge to Ehrman and co-workers at Ohio State University Radio Observatory. Here is where you will find them now and here is more background information. Reading your post gives the impression that you are trying to discredit actual SETI work. Cuddlyable3 (talk) 17:59, 5 August 2011 (UTC)

The report linked above was never subjected to peer review. There is no shortage of academic, industrial, and professional journals that would be happy to publish meritorious, high-quality scientific results related to experimental radioscience. That's all I have to say about this subject. Nimur (talk) 20:08, 5 August 2011 (UTC)

Yes Nimur, professional journals such as Astronomical Journal, Vol. 72, p. 793, Observations of Planetary Nebulae at λ3.75 cm., Author: Ehman, J. R. I believe you have nothing to say about Ehman's work or qualifications. Cuddlyable3 (talk) 21:30, 5 August 2011 (UTC)

Two points: (1) the article you have just linked makes no mention of the Wow! signal; (2) ... because its publication date is 10 years prior to the reported Wow! signal. Did you even read it? It was a brief paragraph about radio observations. I too have authored brief paragraphs about radio observations in peer-reviewed journals; that fact does not mean everything I say about space-aliens is true. The fact that a scientist may have previously presented solid work in a journal does not mean that all his future work is infallible. I did not say anything about Ehman's work or qualifications. I made a very specific statement: this report, which you linked earlier, was not subject to peer review. I don't really feel like your argument is going anywhere; but, you may choose to believe whatever you like. If you want to believe that the Big Ear report and the Wow! signal represent good science, you are entitled to your opinion. Nimur (talk) 23:57, 5 August 2011 (UTC)

Nimur, you complained about Ehman's work in terms of "goofy radio contraption", "populist sensationalism" and "silly and unfounded claims". Some explanation of how a scientist able to present solid work in a peer reviewed professional journal has allegedly decayed so much so fast is called for. What are you saying, if anything, about space-aliens? I indented your post as a reply to mine and hope you don't mind. Cuddlyable3 (talk) 13:49, 6 August 2011 (UTC)

So you argument is... the fact that his work a decade previous was peer reviewed makes up for the fact that the work in question was not? If that's the case, I have some shares in a cold fusion plant I'd like to sell you... and maybe a little intelligent design as well! (As well as some N-rays, if you're feeling flush...) --Mr.98 (talk) 02:41, 7 August 2011 (UTC)

Nimur, somewhere occluded by your mockery you have asserted three - 3 - times that Dr. Ehrman's work report is not peer reviewed and therefore (?) does not represent what you call good science. After defining a question the scientific method starts with observation of data and proceeds to formulating a falsifiable hypothesis. You may find Peirce's explanation of Abductive reasoning enlightening. The SETI activities that you find so discredited has a defined question and is in the data collection phase. It has not yet produced a falsifiable hypothesis for an obvious reason: the present lack of cooperative aliens. When and if these things are in place you may see peer reviewed articles. For now, investigations proceed by the work of many well qualified (but under-funded) workers while you just present your superior thoughts here. Your latest mocking comparisons with cold fusion fraud etc. are offensive. Cuddlyable3 (talk) 10:32, 7 August 2011 (UTC)

There is as of yet no really compelling evidence. As to the likelihood of estimating the probability of anyone being "out there" to receive and reply to a signal, you might check out the Drake equation, which at least helps to clarify exactly what would go into such an estimation of probability. Personally I am pretty pessimistic about the idea of useful two-way communication between Earthlings and anyone else, unless special relativity is very, very, very incorrect or the quantum world grants some kind of work-around. --Mr.98 (talk) 14:22, 4 August 2011 (UTC)

World War II US Submarine Equipment

I would like to know what companies made periscopes and TDC's for US submarines of WW II, please 24.89.36.162 (talk) 11:09, 4 August 2011 (UTC)

On page 280 of U.S. Submarines Through 1945: An Illustrated Design History by Norman Friedman, it states that "C&R" (Convoy and Routing?) called for bids for 10 periscopes to its 1929 specifications in January 1930. It goes on to say that "all three manufacturers bid." This appears to refer to Kollmorgen, Barr and Stroud and Nedinsco (Nederlandsche Instrumentim Compagnie), a subsidiary of Zeiss. Kollmorgen won the bid. Unfortunately, that's as far as Google Books would let me see. This periscope manual published just after World War II lists five manufacturers: the three I've already mentioned, Keuffel and Esser and Bausch & Lomb. According to this Undersea Warfare magazine article, Kollmorgen was also "the dominant U.S. periscope manufacturer" of World War I. Hope that helps. Does TDC stand for Torpedo Data Computer? Clarityfiend (talk) 21:07, 4 August 2011 (UTC)

Temperature inside an atomic nucleus, & what if it were cooled

Hi, I've heard that a sample of rhodium was recently cooled to 10^(-10)Kelvin, just above absolute zero. That being true, isn't it also true that the temperature inside each of the many nuclei in the sample was higher? Would it be possible someday to cool the nuclei as well, slowing the internal motions inside each nucleus? Thanks, Rich Peterson24.7.28.186 (talk) 11:59, 4 August 2011 (UTC)

Temperature is a property of the bulk material. You really start to get into problems if you try to define temperature for an individual molecule or atom. Furthermore, absolute zero only defines zero molecular motion, not zero energy, so there will still be, for example, exchanges of gluons and mesons inside of the nucleus which are holding it together, and those interactions will occur even at fractional kelvin temperatures as low as you note. --Jayron32 12:35, 4 August 2011 (UTC)

• So I've heard(about absolut zero and zero point motion). What's your point?-Rich Peterson199.33.32.40 (talk) 00:34, 5 August 2011 (UTC)

I'm not sure what you mean that absolute zero ... defines zero molecular motion. Surely molecules as well have zero-point motion; it's just smaller than it is for smaller particles. This is a good place to remind everyone that temperature, in general, is not about kinetic energy. --Trovatore (talk) 20:58, 4 August 2011 (UTC)

The nuclei of stable isotopes are already in their ground state and cannot be cooled any further. Unstable nuclei release excess energy when they decay which happens spontaneously. The concept of temperature doesn't really make sense for such a small system. Dauto (talk) 14:26, 4 August 2011 (UTC)

• the thermo article here seems to say that ten fermions is enough. Wouldn't a rhodium nucleus have about 100 fermions?--How do we know a stable nucleus can't be cooled? Are you saying that in principle it can't be cooled further(except, when an alpha particle once in a while tunnels out, say), or that so far it has never been observed or method devised? Thanks.199.33.32.40 (talk) 00:34, 5 August 2011 (UTC)

It can't be cooled because there are no accessible states with lower energy so no energy can be removed from the nucleus. The number of particles here is not important. What's really important is the distance between energy levels which is of the order of 1 MeV. That means that excited states only become accessible at temperatures around 10 billion Kelvin (Give or take an order of magnitude). At energies much lower than that the nucleus effectively behaves as a single particle with no internal structure. Dauto (talk) 02:59, 5 August 2011 (UTC)

Maybe the OP is thinking of a Bose–Einstein condensate. Roger (talk) 14:36, 4 August 2011 (UTC)

What makes you think that could be the case? There is nothing about that in the question. Dauto (talk) 15:41, 4 August 2011 (UTC)

Hmmm, do nuclear isomers represent a "temperature" of sorts? Wnt (talk) 18:17, 5 August 2011 (UTC)

In principle I suppose they could, if you had enough excited states available that the behavior of the system started to become stochastic. But it doesn't make any sense that I can see to say, for example, that technetium 99m has a "higher nuclear temperature" than techetium 99, because it's just a single step from one to the other. There is no identifiable equilibrium around, and without some notion of (at least approximate) equilibrium, thermodynamics makes no sense. --Trovatore (talk) 19:47, 5 August 2011 (UTC)

Well, what about if we(if we could)heated up a stable isotope of uranium into a million degree plasma and observed a .1% decrease in halflife? Wouldn't that mean tunnelling out of the nucleus was becoming more probable, hence indicating a higher temperature inside?RichPeterson199.33.32.40 (talk) 22:07, 5 August 2011 (UTC)

Green birds in Greater London

I was startled by the sight of a flock of about 20-30 birds whizzing past my window yesterday. They were all bright green. I'm no bird expert (hoping someone here is) but they put me in mind of parakeets, but I only got a fleeting glimpse, so can't ofer much more description. Any good ideas what they might have been? (Surely not parakeets?) --Dweller (talk) 12:48, 4 August 2011 (UTC)

Probably parakeets. Grandiose (me, talk, contribs) 12:51, 4 August 2011 (UTC)

Rose-ringed Parakeets (aka Ringnecked Parakeets), perhaps? There are several self-sustaining populations of feral parrots in the UK... --Kurt Shaped Box (talk) 13:04, 4 August 2011 (UTC)

That's unbelievable... thank you, it could well be. If you can point me to any photos of a bird (or flock) in flight, that'd be great. --Dweller (talk) 13:10, 4 August 2011 (UTC)

Is File:Psittacula krameri -Whitefield, Bangalore, India -flying-8.jpg of any use to you? Take a look at Alexandrine Parakeet too - it's a similar-looking (but larger), closely-related species that is also sometimes found as a feral bird, though less often. --Kurt Shaped Box (talk) 13:17, 4 August 2011 (UTC)

Ah. Now I'm not so sure. While I only got a fleeting look at the disappearing flock, I don't recall their tail feathers being so fan-like. I thought their shape in flight might, repeat might have been more swallow-like...? --Dweller (talk) 13:50, 4 August 2011 (UTC)

Okay... How about the Monk Parakeet - in flight: File:Myiopsitta monachus -Florida -two flying-8b.jpg, though I suppose that you would have noticed the grey colouration? I believe that there are some in the UK. TBH, I couldn't tell you what they look like when moving - I've only ever seen this parrot in photos. Have you checked out these species on YouTube, btw - I suspect that there will be HQ video of all of them in flight (probably pets flying around someone's front room), and there may even be vids of the specific flock of feral birds that you saw... --Kurt Shaped Box (talk) 15:22, 4 August 2011 (UTC)

I think they must have been parakeets, especially now you've convinced me there's considerable variety in tail feather appearance between varieties. Yes, I'll check out Youtube. How extraordinary. Never seen them before. --Dweller (talk) 15:27, 4 August 2011 (UTC)

Yes they're parakeets. I see them almost every day now. 82.43.90.27 (talk) 14:17, 4 August 2011 (UTC)

They have certainly been there since the 1960s. I recall as a child being told that they escaped from a pet shop on the Goldhawk Road. There was also a flock of Budgerigars but they don't survive cold winters so well.Elen of the Roads (talk) 15:34, 4 August 2011 (UTC)

Yup, Rose-ringed Parakeets. There is a large population from the west London suburbs (see Kingston parakeets), all the way up the Thames valley. A common sight, though they often draw attention more by their noisy calls. If you saw a flock of thirty, I'd suspect that they were roosting nearby. AndyTheGrump (talk) 15:44, 4 August 2011 (UTC)

Also hawks and owls hate Budgerigars for being tame, its a bit harder for them to catch Paras.

There's been a wild flock of wild parakeets at Englefield Green for over ten years now but recently the population seems to have exploded for some reason. Was at a barbee over at Egham on Friday, there were litteraly hundreds of them flying over the garden, some came within 10 feet of us. We were like Whoa!!! So spectacular... If you want to photo them Runnymede Park is a happy hunting ground. FeydHuxtable (talk) 15:58, 4 August 2011 (UTC)

Just to prove the point about how common they are, I've just had two fly past my window (SW London suburbs), squawking loudly... AndyTheGrump (talk) 18:06, 4 August 2011 (UTC)

I can only assume nothing eats them. London clearly needs the return of the Red Kite, successfully reintroduced into Northamptonshire about 10 years ago. Elen of the Roads (talk) 20:23, 4 August 2011 (UTC)

I suspect that a Kite would prefer easier targets. The parakeets gregarious nature will make preying on them difficult, and they are agile fliers - and Kites generally prefer to scavenge anyway. One might be tempted to introduce the parakeets natural predator (whatever that is) to control the population, but that is a tactic that has misfired before. I think the ecosystem of south-east England has bigger problems than the parakeets anyway - and ironically, the London suburbs, where our noisy friends have settled, are probably more ecologically diverse than the small remaining areas of 'nature' we have. Then again, for a bird that evolved in the mountain uplands, an ecosystem consisting of tree-filled gulleys between vertical cliffs is probably ideal - we think we live in a man-made environment, but the parakeets may see it differently. AndyTheGrump (talk) 03:42, 5 August 2011 (UTC)

More info on parakeets in London here, here, and here. What I find unbelievable is that there are some people in London who don't know about them... !! Ghmyrtle (talk) 09:13, 5 August 2011 (UTC)

I live in east London, a mile and a bit from the Olympic Park, and had never seen one until a visit to Kensington Gardens last month. It seems they are fastidious in their choice of neighbourhood! Alansplodge (talk) 16:48, 5 August 2011 (UTC)

what effects onbody organs human hanging death

dear sir,

human hanging death ,deadd body organs is it use full for donate or transplent like eye,kidney,lungs .

after death how much time for donate human body organs

thanks & regards shivkumar(india) — Preceding unsigned comment added by 27.97.208.211 (talk) 17:47, 4 August 2011 (UTC)

A better question is what effects DON'T onbody organs human hanging death. --Goodbye Galaxy (talk) 18:33, 4 August 2011 (UTC)

A lot depends on the exact method of hanging used. See Hanging#Medical effects for details. Beeblebrox (talk) 18:53, 4 August 2011 (UTC)

At the very least, it pretty much rules out a neck transplant. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:17, 4 August 2011 (UTC)

removed OP's email Bazza (talk) 15:09, 5 August 2011 (UTC)

Good question. I'd think that organs in the head, like the eyes, might be damaged by a spike in blood pressure. The jerk at the bottom isn't so severe that I'd expect it to damage the organs of the abdomen. Then the other issue is that you'd need to remove those organs immediately upon death. This contrasts with cases where somebody is brain dead, but the body lives on in a hospital, where the organs don't need to be removed until the recipient is prepped for surgery. So, this might be a rather limiting factor with hangings. StuRat (talk) 22:01, 5 August 2011 (UTC)

Mike the Headless Chicken lived for 18 months. This suggests that a brain-dead hanged body can be kept alive for a while. Do not try this at home. Cuddlyable3 (talk) 13:32, 6 August 2011 (UTC)

Freeview signal, UK

1) Why do some channels have a stronger signal than others? Shouldnt they all be the same? 2) How many Freeview channels could be encoded into one analogue TV channel? 92.24.140.101 (talk) 19:41, 4 August 2011 (UTC)

The answer to 1 is that it still depends how far you are from the television mast, and what the intervening terrain is like. As to 2 - I'll leave that to the engineers among us. --Elen of the Roads (talk) 20:26, 4 August 2011 (UTC)

Almost all UK TV terrestrial TV reception antennas are directional Yagi antennas with reflectors. They have to be pointed at the broadcasting tower. To receive signals from two different towers you'd need two different antennas feeding the same outlet, which is a very rare thing to do. So, for a given receiver, if you're receiving two channels they're still from the same tower. -- Finlay McWalter ☻ Talk 20:42, 4 August 2011 (UTC)

Freeview (that's UK Digital Terrestrial Television broadcast using the DVB-T standard) broadcasts a bunch of channels in one digital stream, at a given frequency. That's called a "multiplex" - this page lists the different multiplexes. So you'd expect to see the same signal strength for BBC1, BBC2, BBC3, BBC-News, and the others in the same miltiplex (because they're all carried on the same stream on the same frequency). A different multiplex, at a different frequency, is going to have somewhat different strength: so ITV1 and Five should be the same as one another, but not necessarily the same as BBC1. Wikipedia has some pretty detailed articles about specific transmitter towers - looking for example at Emley Moor it lists the frequencies at which each multiplex is broadcast; with a bit of digging you should be able to figure out the tower and frequencies that you're receiving. As you can see in the Emley Moor article they don't broadcast all the muxes with the same power. Even if they did, radio signals at different frequencies propagate differently: they interact differently with the atmosphere and with water suspended in it, they diffract over the terrain differently, and interact differently with your general-purpose TV antenna. -- Finlay McWalter ☻ Talk 20:28, 4 August 2011 (UTC)

As to your second question (about how many digital channels one can fit into the space freed by turning off an analog TV channel in analog switchoff) - it depends on how they configure the MPEG compression for a given subchannel - they're currently fitting 7 conventional subchannels onto MUX2, for example. HD channels will typically consume much more bandwidth, and so you'd expect to see fewer on a given MUX. This is much the same arrangement for digital radio (T-DAB); the UK's DAB service has been criticised for having too many channels and so having to reduce the effective bitrate for each stream (see this article). A very informative paper about analog switchoff in Europe is here. -- Finlay McWalter ☻ Talk 21:09, 4 August 2011 (UTC)

Brownian ratchet

Hi, I have a couple of questions about the Brownian ratchet setup, but with ratchet disconnected, leaving just the paddle wheel, free to rotate as it chooses. Assume the paddle wheel is massless and frictionless.

1. Does the paddle wheel do a random walk, so that eventually it will inevitably have rotated by any given amount, just as tossing a coin will inevitably eventually produce any given surplus of heads over tails or vice versa? If so, does this rotation occur at zero energy cost?

2. As the vanes of the paddle increase in size (remember it's massless and frictionless), all other things being equal, do the random movements of the wheel, measured as angular displacement, become larger, smaller, or remain the same?

86.181.170.252 (talk) 19:59, 4 August 2011 (UTC)

1. Yes, and yes.
2. The random movements become smaller because the number of collisions grow proportionally to the area but the surplus collisions in one direction due to random walk only grows proportionally to the square root of the number of collisions becoming statistically less important for larger objects.

Dauto (talk) 20:17, 4 August 2011 (UTC)

Thanks. As regards (2), I can see the surplus grows on average with the square root, but isn't the surplus the only thing that matters? More surplus = greater movement? 86.181.170.252 (talk) 21:13, 4 August 2011 (UTC)

If the paddle wheel is massless, its behavior when a particle hits it doesn't seem to be very well defined. What happens to it and to the particle? Rckrone (talk) 23:22, 4 August 2011 (UTC)

The massless thing was inspired by the article Brownian ratchet, but looking more carefully, I see that actually only the conecting rod is said to be massless. I don't exactly understand why, if the other parts have mass, it's necessary to specify that the rod is massless. But, in any case, if it makes no sense for the paddle mass to be actually zero, then can we just say that it is negligibly small? I guess really I just didn't want the increasing mass of a huge real physical wheel to be taken into account when calculating the scaling behaviour that I was asking about. 86.181.170.252 (talk) 23:41, 4 August 2011 (UTC)

Yeah, after thinking about it I realized that if you just take it to be vanishingly small, the spot on the wheel where the particle hit would get velocity twice the component of the particle's velocity in the angular direction, so it's not really a problem. Anyway, the angular velocity of the paddle wheel after a collision would depend on how far from the axis the particle hit it. If the wheel is bigger, more particles are hitting farther from the axis so the angular speed after each collision would be smaller on average. Rckrone (talk) 23:48, 4 August 2011 (UTC)

So, if k^2 is the vane area, we're first of all saying that average surplus collisions is proportional to k. Then these collisions are evenly distributed over radial distance 0 to some number proportional to k. And this all adds up to a net decrease in average angular motion as k increases? 86.181.170.252 (talk) 00:53, 5 August 2011 (UTC)

If the mass of the paddle wheel is small compared to the particles, its angular velocity doesn't really accumulate. Instead the angular velocity at any given time is completely determined by the last particle to have hit it. That said, the average angular speed depends only on the speed of the particles and the radius at which they hit the paddles. The number of collisions doesn't matter. Rckrone (talk) 01:59, 5 August 2011 (UTC)

No wait, this isn't quite right. The paddle wheel basically gets pushed around bouncing of the particles, but if two particles come pushing it from opposite directions they can pinch the paddle wheel and be deflected in some way. I think the paddle wheel speed will get very high in this situation as it gets reflected back and forth, but I'm not sure what the speed will be after the particles are deflected. I think the moral of the story is that the wheel behaves weirdly if it doesn't have appreciable inertia. Rckrone (talk) 02:10, 5 August 2011 (UTC)

The wheel speed can be calculated using the Equipartition theorem which gives

$\langle E\rangle ={\frac {1}{2}}I\langle \omega ^{2}\rangle ={\frac {1}{2}}k_{B}T$

Where omega is the angular speed. That gives unsurprisingly an infinite speed for a massless wheel. Dauto (talk) 03:11, 5 August 2011 (UTC)

Although the momentary speed might have to be factored in somewhere in the calculations, what I'm ultimately interested in is the overall rate of progress of the wheel. I may have this wrong, but if it's a random walk, then I think there should be a single parameter characterising the "speed" of the walk. To model this we can say that in each very small timestep Δt, the wheel will move c*sqrt(Δt) radians in a random direction, then c is the number I'm interested in (does that sound right?) 86.181.170.252 (talk) 02:34, 5 August 2011 (UTC)

Living liquid

Would it be possible to have a living liquid? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 20:47, 4 August 2011 (UTC)

Do you mean like a Changeling? Dauto (talk) 20:53, 4 August 2011 (UTC)

Or an amoeba? --Jayron32 20:55, 4 August 2011 (UTC)

Yeast frequently exists as a liquid. Those eternal cell lines that the oncologists use are liquids. Amoebae are just liquid in a bag - but then the human body is mostly water. I suppose it depends on how you define 'liquid' in a biological, rather than a physical sense. --Elen of the Roads (talk) 21:17, 4 August 2011 (UTC)

Yeasts (and other laboratory cell lines) exist as cells suspended in a liquid; it is incorrect to describe them as liquids. Cells don't exist as single phases of matter. They contain several distinct solid, liquid, and 'fluid' phases. TenOfAllTrades(talk) 23:31, 4 August 2011 (UTC)

This is a somewhat complicated question to answer. When the molecules suspended in a liquid become too large, it starts to be called a "colloid"; if they're large enough it becomes a "solid" (like plastic). I vaguely remember reading that around the turn of the 20th century much was made of the colloidal nature of life, before thinking about it that way became passe. In somewhat a similar way, a cell is made up of a droplet of liquid surrounded in a membrane which is also liquid (though without more reinforcement from extracellular matrix (more or less a solid) such a cell is quite vulnerable anyway) - but is a vesicle or a liposome a "liquid" in the same sense that a homogenous solution would be considered one? So when asking how to make liquid life... well, it seems like mostly a matter of creative description. If you want to avoid the cell membrane, you might consider a virus; or you could imagine some complex "cell" in which all the biochemical components are covalently linked together so no membrane is needed; but if it's too big it would sediment in a test tube on standing and would that count as a liquid? ... I think the boundary blurs as you look at it. Wnt (talk) 05:18, 5 August 2011 (UTC)

I meant (sort of) a large multicellular organism that is held together only by surface tension and the other forces holding liquids together. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 11:50, 5 August 2011 (UTC)

How about some slime mold? Wouldn't that be a viscous liquid for some species anyway? Googlemeister (talk) 16:21, 5 August 2011 (UTC)

Well, the issue is, what's the difference between a dissolved solid and a wet solid? Especially when it contains a vast range of different compounds? Because proteins crystallize, we know that their interactions are sufficient to make them solid; so in order to exclude forces that hold solids together, the hypothetical lifeform should have no protein-protein interactions - or at least none on a large scale (how large?). Non-Newtonian fluids are confusing enough with just one or two ingredients. Wnt (talk) 16:44, 5 August 2011 (UTC)

Hanging: suicide or execution?

If someone is about to be judicially hanged, but they jump off the platform themselves, is it considered suicide or execution? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 20:50, 4 August 2011 (UTC)

You're thinking of the last man to enter Parliament with honorable intentions? --Trovatore (talk) 20:51, 4 August 2011 (UTC)

In UK law it made no difference - death on the scaffold was always considered to be execution, particularly as the death penalty usually specified what was to be done with the body. In any case, suicide was until recently considered a mortal sin by the Christian church, while the abovementioned Guido Johnson was (possibly still is) hailed as a martyr. --Elen of the Roads (talk) 21:38, 4 August 2011 (UTC)

1) The Catholic Church does not consider Guy Fawkes a martyr, and I'm not sure it ever did. He was executed for trying to kill people, not for his faith. 2) The official position of the Catholic Church on suicide includes "Grave psychological disturbances, anguish, or grave fear of hardship, suffering, or torture can diminish the responsibility of the one committing suicide." [3] I think avoiding being drawn and quartered is a pretty fair 'grave fear' of 'torture', especially given that the torture was intended to imminently kill him anyway. 86.161.210.242 (talk) 12:20, 5 August 2011 (UTC)

Surely a person who jumps away from certain death is no suicide, whether he breaks his neck or not. It makes me wonder, though, whether we would be unpleasantly surprised to find out who is celebrated as a martyr on September 11, 2201... Wnt (talk) 23:23, 5 August 2011 (UTC)

We would be pleasantly surprised just to be alive in 2201. Cuddlyable3 (talk) 13:26, 6 August 2011 (UTC)

At least as far as the long drop method formerly used in the UK is concerned, there was no platform to jump off: the drop was achieved by a large double trapdoor that opened under the victim. Picture here. AndrewWTaylor (talk) 11:29, 5 August 2011 (UTC)

August 5

Question (acetone)

I used Acetone to clean my car windows. The fumes and vapors from the Acetone got so bad that it irritated my eyes and body. What can I do to get rid of the fumes and vapors? Thanks and hope to hear from you soon. Thanks for the answers, is there any more suggestions. — Preceding unsigned comment added by 174.111.55.161 (talk) 01:30, 5 August 2011 (UTC)

If that question still requires an answer, let us know. μηδείς (talk) 01:48, 5 August 2011 (UTC)

Roll down the windows and drive for an hour with the air blasting through the car. You might wish to read our acetone article. Looie496 (talk) 01:50, 5 August 2011 (UTC)

If the vapour saturation is high enough, duck and light a match. Plasmic Physics (talk) 02:02, 5 August 2011 (UTC)

Watch out, some idiot will try that and sue... but seriously, acetone is a small, highly volatile molecule which easily diffuses into the air and blows away. Also, in small amounts acetone is a normal metabolite in the human body - though in diabetics it can build up to acetone breath and become part of a pathology. So as long as you let the car air out enough that you don't smell it (assuming a normal sense of smell) it should not be a hazard at trace levels. Wnt (talk) 05:24, 5 August 2011 (UTC)

Can hardly sue Wikipedia for misinformation, it is a wikia afterall. Plasmic Physics (talk) 08:04, 5 August 2011 (UTC)

No, but they can get a court order to force Wikipedia to reveal your identity, and then they can sue you. --Jayron32 16:16, 5 August 2011 (UTC)

That would be a problem for them, my identity is not contained with Wikipedia. Plasmic Physics (talk) 19:33, 6 August 2011 (UTC)

Not at all. Wikipedia doesn't have a list Plasmic Physics = David Smith of 327 Magnolia Way, Cardiff completely fictional, off the top of my head, no real person or address to my knowledge, but they can access all the IP addresses you have ever used with this account. This is not easily available, nor just handed out (see WP:CHECKUSER), but they can certainly look it up and hand it over if necessary. These IP addresses will probably mostly correspond to your Internet Service Provider, who will know who was assigned which IP addresses at what time. Some addresses might be your local library, some might be other houses and places, but you can be found if someone really wants to find you. (You could make it a lot harder in some ways, though, if you could be bothered: most people don't bother unless their access to something fun is cut off without it). 82.24.248.137 (talk) 23:08, 7 August 2011 (UTC)

Luckily, where I live you're protected from other people's misuse of commonsense, unlike the USA. Plasmic Physics (talk) 23:35, 7 August 2011 (UTC)

Is using acetone to clean car windows a good idea? Seems like a great way to ruin the rubber seals and allow leaking later, or to damage the paint on the car. Googlemeister (talk) 12:49, 5 August 2011 (UTC)

Agreed, bad idea. Use the blue window washer solution made for cars. But, now that the deed is done, I suggest rinsing it thoroughly, rolling all the windows down, and letting is sit for a while. StuRat (talk) 21:51, 5 August 2011 (UTC)

Thomisida

White and pink crab spider

. Good morning everybody. This spider is surely a member of the Thomisidae family. But I'd like to know the exact species. I photographed it in July, in my garden, lower St-Lawrence region, Prov. of Quebec, Canada. Dhatier (talk • contribs) 03:21, 5 August 2011 (UTC)

Good morning. That is a very fine photograph. Cuddlyable3 (talk) 12:40, 5 August 2011 (UTC)

It's a goldenrod crab spider, Misumena vatia, the most widespread of the genus Misumena (flower crab spiders). Occurs all throughout the northern hemisphere. I have requested a rename.-- Obsidi♠n Soul 16:00, 8 August 2011 (UTC)

WHAT PERCENT OF THE PLANETS IN THE GALAXY HAVE LIFE

i know it is hard to say for sure, so your best guess is fine. also, do most planets with life have aliens (sentient) or just trees and bugs and single cell organisms?--Fran Cranley (talk) 03:42, 5 August 2011 (UTC)

The short answer is that nobody knows. The long answer is to look at the Drake equation, fill in the necessary fields with whatever value you consider appropriate, and then admit that you don't know either. All we know is that this planet has life, and that it took a long time to evolve to its present state - so a modicum of care over the health of the planet might not be misplaced. AndyTheGrump (talk) 03:50, 5 August 2011 (UTC)

From what we have observed, it seems there could be 1,235 planets outside the solar system that we can detect (as of Feb 2011). There are also 8 planets in this solar system. As far as we know only 1 of them has life (but we could be wrong). So if you want to calculate a percentage based exclusively on what we have observed of the Galazy so far, it is 0.0805%. Obvioulsy there is a vast amount of unobseverd planets, so that percentage doesn't mean anything at all. --Lgriot (talk) 11:21, 5 August 2011 (UTC)

We don't know if any of the "observed" extrasolar planets have life ("observed" in quotes because we mostly just deduce their existence indirectly from spectrographic and brightness variations when observing their parent stars). We have found no blindingly obvious signs of life on other planets in the solar system, but we have extremely rarely even looked for signs of life at any of the known or suspected extrasolar planets. Our tools for doing that are wholly inadequate at the moment. Indeed, our inadequate observation equipment very much limits the type of planets we can detect to implausible candidates for life. Life on Earth evolved essentially as soon as the surface cooled down. This suggests that primitive life may be very frequent. On the other hand, complex life seems to have taken ~3 billion years to evolve from single-celled ancestors, and wether Earth has evolved intelligent life yet is debatable ;-). --Stephan Schulz (talk) 11:44, 5 August 2011 (UTC)

Where do we find anyone intelligent enough to debate that? Cuddlyable3 (talk) 12:38, 5 August 2011 (UTC)

I believe life must be far more prevalent than intelligent life. As noted above, life on Earth seemed to start as soon as the proper conditions existed, so I would assume this would also happen elsewhere. However, if there were many planets with advanced technology, then we'd expect to have heard from some by now. Perhaps there's a middle ground, with many planets containing whales and such, which are somewhat intelligent, but either not quite intelligent enough for extra-planetary communication, or simply lacking the hands, tentacles, etc., needed to do so. StuRat (talk) 21:46, 5 August 2011 (UTC)

What I'm a bit scared about is that the reason for the Fermi paradox may well be that technological civilisations destroy their habitat (and thus themselves) before they learn to leave it... --Stephan Schulz (talk) 23:46, 5 August 2011 (UTC)

Simple solution to that: don't try and learn to leave it. We'll live forever, then ;) --KägeTorä - (影虎) (TALK) 14:15, 6 August 2011 (UTC)

Water flowing on Mars???

A Martian dry river bed?
~AH1 ^(discuss!) 14:06, 8 August 2011 (UTC)

NASA is saying they see evidence of briny water flowing on present-day Mars, perhaps under the surface. How on, erm, Mars is it possible for water to be liquid when it should freeze or evaporate in the cold and thin atmosphere? Wnt (talk) 05:01, 5 August 2011 (UTC)

The simple answer is that the conditions under the surface must be different enough from those at the surface to circumvent the problem you describe. Dauto (talk) 06:14, 5 August 2011 (UTC)

Do planetary geologists predict higher pressures underground on Mars sufficient for liquid water to exist? -- 203.82.81.40 (talk) 07:39, 5 August 2011 (UTC)

The key is "briny". Pure water would definitely not be in a stable liquid state at the temperatures that they observe at these sites (250 to 300 K). Salt decreases the melting point of water (by up to 70K, they say) and makes it more stable. --Wrongfilter (talk) 11:28, 5 August 2011 (UTC)

I see someone has started a pretty nice article on seasonal flows on warm Martian slopes, which clarifies that even though the water may be only as salty as Earth's oceans, the slopes are 250 to 300 K. I hadn't realized that anywhere on Mars ever got up to such balmy temperatures! But what still confuses me is why it doesn't evaporate instantly. Is there some way that a relatively thin layer of soil could maintain a partial atm of pressure? Wnt (talk) 16:18, 5 August 2011 (UTC)

Yes, that is what I am wondering. From a Terran point of view, the atmosphere of Mars seems rather vacuous (MSL pressure of ~ 0.6% earth atmosphere. Also, where can I read abou the physical properties of brine? Wrongfilter suggests a 70K freezing-point depression, but our brine article gives 21.1 K (delta temp). Can the boiling point be elevated over this at such low pressures? -- 203.82.93.106 (talk) 20:23, 5 August 2011 (UTC)

I recall reading that Mars was at 20 degC when one of the probes landed on it, but I don't recall which probe it was and if that value turned out to be a measurement error or anomaly. Googlemeister (talk) 20:26, 5 August 2011 (UTC)

Per Climate of Mars the orbitally observed range is -143 to +27 C with a mean temperature of -55 C. The upper part of that range would allow liquid water even without solutes, but it would still turn to vapor under the very low pressures present at the surface. Dragons flight (talk) 00:09, 6 August 2011 (UTC)

Some thoughts:

1) Mars may have had a thicker atmosphere in the past. The magnetic field of a planet seem important here, as it deflects the solar wind, which would otherwise blow the atmosphere away. Early Mars likely had a strong magnetic field, like Earth, due to a molten iron core.

2) Modern Mars is rather desert-like, and deserts have extremes of temperatures. So, while the average temperature may be much lower on Mars, those portions in direct sunlight may warm up considerably, with little atmosphere and no oceans to support cooling and redistribution of that heat by convection. StuRat (talk) 21:38, 5 August 2011 (UTC)

From [4] it appears that the observed flows occur just a little but north of the "frost line" in the "southern extreme transitional" zone of Mars - not in the tropics. From File:MarsTopoMap-PIA02031_modest.jpg it appears that most of this region is actually higher than the average terrain on Mars, at +0 to +4 relative to something. (For the Mariner probes the zero level used was the triple point of water, but I don't know how that relates to the scale on this figure). So... although supposedly some locations on Mars might once in a blue moon rise up to as much as a balmy 80 degrees Fahrenheit, these slopes are cold - -70C to -100C.[5] But this is also a region of climate extremes, and I'm not quite sure what the climate is as the water is flowing. The atmosphere should never be dense enough to contain the water. Water on Mars gives an explanation that maybe the water starts flowing and freezes along the path, containing liquid water beneath it at higher pressure... not sure I believe that, but then again, at such tiny pressures as this, the force needed to keep the pressure qualitatively higher isn't really that much. Hmmm... look forward to the explanation from the professionals. Wnt (talk) 19:19, 8 August 2011 (UTC)

Claims of Scientific Evidence Against Evolution

I have heard some people claim that there is scientific evidence against evolution. Is that true? If so, then what they? Are they really scientific evidences against it? — Preceding unsigned comment added by 110.174.63.234 (talk) 08:22, 5 August 2011 (UTC)

No they are not real scientific evidence against it. Real evidence agaisnt it would be for example fossils of rabbits in the precambrian. Nothing like has ever been observed. It is just people making it up, because they don't want to accept the massive biological evidence AND DNA evidence, AND fossil evidence that are all pointing to the same obvious conclusion: Evolution is a fact.--Lgriot (talk) 11:30, 5 August 2011 (UTC)

FYI, we have articles directly relating to Lgriot's claims: Precambrian rabbit & Evolution as theory and fact. — Scientizzle 15:29, 5 August 2011 (UTC)

The Talk.origins website has a taxonomically organised list of claims by creationists. Notice "claims", not "scientific evidence". The list is here. --Stephan Schulz (talk) 11:48, 5 August 2011 (UTC)

Fossil rabbits in the Precambrian layer wouldn't disprove evolution. Even I you could prove they were definitely from that time period, and weren't just some later insertion, it would only disprove our current models of common descent and maybe our current taxonomical theories. To disprove biological evolution itself would require something much more basic, like disproving that traits are physically inherited, or proving that each species can only vary within certain narrow parameters and that they therefore cannot drift more than a certain genetic distance from a somehow hardcoded 'typical' version of the species, or that no mutations ever produce viable offspring. Of course, we have such a wealth of data showing the opposite that you would also have to show how all this data could be wrong, while proving this unlikely scenario. It would have to be a proof on such a basic level, because biological evolution is a mathematical inevitability once you have inherited traits, variation in traits, and variable reproductive success. Even if the inherited traits had no impact on reproductie success, you would have genetic drift which is sufficient to establish new species if populations are isolated. This is, of course, why even many of those pushing for a creationist interpretation start introducing things like 'Intelligent Design' and 'microevolution': because any halfway intelligent person who looks at the evidence can see that evolution simply has to happen, unless our most basic assumptions about inheritability, or even cause and effect, are fundamentally broken. 212.183.128.47 (talk) 12:03, 5 August 2011 (UTC)

it would only disprove [...] maybe our current taxonomical theories. Maybe??? Come on, mamals during the precambrian era!? it would maybe disprove our current taxonomy? It would be earth-shatering. We'd have to review everything end-to-end. I'd personnaly start wondering if something is playing a little game with us. And I'd be very interested in those theories that try to reconcile these rabbits with the taxonomy we now have. That would be a very interesting debate. --Lgriot (talk) 13:29, 5 August 2011 (UTC)

I can't help it: I read too much scifi. Time machine? Aliens? Separate descent of animals up to rabbits on Atlantis, spreading to the rest of the world when it sank? Rabbit-shaped plant roots? Rabbits turn out not to be mammals? Given that any theory has to explain why all the other evidence suggests our current theories as well as explaining the rabbit, I wouldn't like to say with certainty that it would actually suggest our underlying theories of how taxonomy works would necessarily be wrong, since it would be so unlikely anyway that an explanation that looks unlikely now might look more likely in the event. But even if we had to rework all of that from the bottom, it still wouldn't disprove evolution. 86.161.210.242 (talk) 15:23, 5 August 2011 (UTC)

Perhaps rabbits evolved intelligence and made an attempt at paleontology, with some casualties. ;) But seriously, there is a point there that if we can think of excuses for such a gaping hole in the theory, there's some doubt as to the falsifiability of the theory. I don't think this is a problem limited to evolution though - any theory which is extremely fundamental to a science becomes difficult to falsify because there are so many lines of proof favoring it and so many ways to explain away one experimental observation (the Voyager data questioning whether gravity is really inverse square, for example). There may indeed be some risk that a society could be "blinded with science" this way, but I doubt evolution (or gravity) is the example. Wnt (talk) 16:26, 5 August 2011 (UTC)

And, while we are on the subject, "What, if anything, is a rabbit?" [6] AndyTheGrump (talk) 16:36, 5 August 2011 (UTC)

Maybe finding the Precambrian fossils of this rabbit would convince me, or at least convince me to run away... very, very fast. --Modocc (talk) 21:20, 5 August 2011 (UTC)

You mean Pioneer, not Voyager. The Voyagers weren't spin-stabilized, instead achieving attitude control through the frequent firing of thrusters. The resulting unpredictable little accelerations are much too big for it to be possible to determine if the Voyagers have also experienced the Pioneer anomaly. Red Act (talk) 17:35, 5 August 2011 (UTC)

Good catch! No wonder I didn't find the link. ;) Wnt (talk) 18:11, 5 August 2011 (UTC)

The honest answer is, of course there's scientific evidence against evolution. There's scientific evidence both for and against practically any proposition you care to name. The problem is to weigh the evidence, and figure out, on balance, which side does it support more than the other. --Trovatore (talk) 22:35, 5 August 2011 (UTC)

Come on then. Give us the answer to the OP's question. What IS that evidence? I can't think of any. HiLo48 (talk) 22:47, 5 August 2011 (UTC)

I'll answer, but before I do let me clarify that I'm a biologist myself and pretty much totally convinced of the validity of evolution. The strongest evidence against it, in my view, would be cases where biological systems seem to show very sophisticated engineering, in ways whose natural origins we don't yet understand. One very basic example is the genetic code, using triplets of DNA to code for amino acids; a less basic one that particularly strikes me is the modular structure of the cerebellum. Looie496 (talk) 23:28, 5 August 2011 (UTC)

I wasn't even necessarily going that deep. My point is more that evidence comes in chunks of all sizes; sometimes you put together a lot of little pieces of evidence, none of them very strong in themselves, to reach a scientific conclusion. And there are certainly various small pieces of evidence against evolution. For example, whenever we think that species B evolved from species A, but there must have been an intermediate type C, then if evolution is true, it is more likely to find C in the fossil record than if evolution is not true. If, then, we have not found C in the fossil record, then in the sense of Bayesian inference, that is a small, scientific, data point against evolution. It is not convincing in itself, but it is the sort of thing that could be added to a scientific case against evolution, and is therefore evidence. --Trovatore (talk) 23:58, 5 August 2011 (UTC)

Creationists seeking scientific evidence to refute evolution is as absurd as evolutionists seeking scriptural support to deny creationism.Wolfgangus (talk) 09:20, 6 August 2011 (UTC)

Creation Evidence Museum! Axl ¤ [Talk] 21:42, 7 August 2011 (UTC)

Everything you wanted to know about inheritance of acquired characteristics and more: http://www.guardian.co.uk/science/2010/mar/19/evolution-darwin-natural-selection-genes-wrong . ~AH1 ^(discuss!) 14:04, 8 August 2011 (UTC)

Fiat leporēs: The Spirit of God was hovering over the Precambrian waters, and he had a nasty flu that day from all the volcanism and shiz. And God said, 'Wed der be twewobits,' and lo there was wabbits. -- Obsidi♠n Soul 06:12, 9 August 2011 (UTC)

Radio frequencies

I recently noticed my local FM station at 107.9 can also be heard at 86.5. Why is this? I know that the Intermediate frequency is 10.7 MHz, and 107.9 - 10.7 -10.7 is 86.5, though I have no idea how this plays into effect. ^Avic_ennasis @ 13:31, 5 Av 5771 / 5 August 2011 (UTC)

If you look at the station's website, you might find that it has a main transmitter and a relay situated somewhere else, in order to get better coverage. Hence, they'll be on separate frequencies.--Aspro (talk) 13:49, 5 August 2011 (UTC)

(ec)Broadcasters want everyone in a large area (say all of Belgium or all of Arkansas) to hear a station. But a single tower broadcasting will not reach the whole territory (for reasons of power use and topography). So they (or usually mast operating companies like Arquiva) built multiple towers (usually on top of hills) to "tile" the whole territory. In order to service people in remote valleys and people with rubbish antennas, these transmitters are a bit overpowered (than they'd need to be if everyone had a big antenna on their roof). So if you live roughly between two towers, you can see both. In #Freeview signal, UK, above, we talk about the same scenario for TV reception. But whereas TV antennas are (kinda) directional, you'd usually receive FM with an omnidirectional antenna, so you can receive signals from both towers on the same radio receiver, without having to do anything to the antenna. To prevent the two towers from interfering with one another, they transmit on different frequencies. For you, between the two, you're getting a reasonably strong signal from both. You've not said what country you live in (and where) which would help us know precisely what's up, but the scheme is much the same the world over. You can search the website of whatever authority controls broadcast in your country (e.g. in the US it's the FCC) and find the locations of all the regional radio and tv broadcast towers (and their boosters), which usually also lists the channel assignment (the frequencies) each station is broadcast on from that tower. Armed with that you can figure out the physical location from which you receive every signal. TL;DR - you're getting signal from different towers. -- Finlay McWalter ☻ Talk 13:50, 5 August 2011 (UTC)

I understand the use of multiple towers/frequencies to reach a larger audience. However, unless I'm mistaken, most FM radios in the US don't go below 87.5, which is why I'm surprised to hear content on 86.5. Also, if it matters, the callsign of the station heard on 86.5 is "Y108", the same as 107.9. If they were intentionally broadcasting on 86.5, wouldn't they have to identify that in some way? ^Avic_ennasis @ 14:04, 5 Av 5771 / 5 August 2011 (UTC)

The original signal at the intermediate frequency (IF) has to be mixed with another frequency to be converted to the carrier frequency. Mixing is kind of like adding and subtracting frequencies, so to get 107.9 MHz from 10.7 MHz, you need to mix it with 97.2 MHz (97.2 + 10.7 = 107.9). However, on the output of the mixer there will also be an identical signal at 97.2 minus 10.7, or 86.5 MHz. There is meant to be some filtering to remove the 86.5 MHz signal, but in this case some energy managed to get through to you, since none of the components are ideal. —Akrabbim^talk 13:55, 5 August 2011 (UTC)

I think your math is a little off. :-) If it helps, the local station is WDSY-FM. ^Avic_ennasis @ 14:04, 5 Av 5771 / 5 August 2011 (UTC)

Thanks, typos corrected (87.5 --> 86.5). —Akrabbim^talk 14:11, 5 August 2011 (UTC)

In that case, it might be a pirate re-transmission. Is this the first time you have noticed it; in other words, could it have just popped up during the summer vacation like so many pirate stations. Just looked up the US frequency allocations and this is for television, non government broadcasts; that finishes at 88mhz with FM radio above that. So, off-hand I cant think of any legitimate reason that it should be there. Also, if you can receive it way-down-there on 'your' radio, it suggest to me there might be a slight chance that you also have your rig wired up to a rotatable array of some sort, in which case you could have a go at DXing its location and reporting it.--Aspro (talk) 15:02, 5 August 2011 (UTC)

Akrabbim is correct and the effect is described at Superheterodyne receiver#Image frequency (fimage). The guesses above about multiple transmitters, pirates and a direction-finding rig are all wrong. Cuddlyable3 (talk) 16:09, 5 August 2011 (UTC)

The "Laotian bird" Nock-ten (2011)

I have posted a question here at the language desk asking for a reliable source explaining the nature of the "Laotian bird" for which this storm is named. Comments there by those who might have a clue would be appreciated. μηδείς (talk) 15:57, 5 August 2011 (UTC)

I don't know. But a source that looks like it actually took a moment to do some translation says it's Laotian for "bird" (rather than a kind of bird).[7] True, most of the world's media says that it's a "Laotian bird", but I have a sinking feeling they're all copying each other and a 2004 Wikipedia article. [8] This becomes increasingly a worry - as Wikipedia becomes the only easy source for looking up certain things, we may end up breathing our own exhaust. Wnt (talk) 17:28, 5 August 2011 (UTC)

Maybe we're looking in the wrong place. Tropical Storm Nock-ten (2011) says it was the Japan Meteorological Agency (JMA) which gave the storm that name. Maybe it would be more reasonable to assume that it's a Japanese word, maybe for a Laotian bird. HiLo48 (talk) 22:39, 5 August 2011 (UTC)

Japanese words don't end in -ck, either by pronunciation or spelling. The -ck spelling convention alone, limited pretty much to English and German, makes the Lao-ness of the word as written suspect. We seem to be dealing with a word reported at several removes from its origin, like the various English transliterations of the Russian name Fyodor or Feodor (spelt Фёдор) which comes from the Greek Θεόδωρος (Theodōros), "Theodore". The best hint I have found so far is that the Thai language wikipedia article for the storm links to the Thai article on kingfishers. μηδείς (talk) 03:37, 6 August 2011 (UTC)

Is this helpful? It suggests that the Thai for "kingfisher" has both the syllables "nok" and "ten" in it. Bielle (talk) 03:45, 6 August 2011 (UTC)

See Lists of tropical cyclone names#International names. Given the way the naming works, there's little doubt it came from Laos. Regional Specialized Meteorological Centre in Japan which is operated by the Japan Meteorological Agency is in charge of the naming but they use the process outlined there/Tropical cyclone naming#Western Pacific/[9]. Lao script gives wiktionary:ນົກ or nōk as meaning bird. That article and Romanization of Lao isn't particularly clear on what, if any specific, romanisation is normally used by the Laotian government but I presume the specific romanisation was submitted by whoever in Laos was in charge of submitting the name. Given the relationship between Thai and the Lao language and the above, it seems likely the meaning is something akin to kingfisher. Nil Einne (talk) 09:58, 6 August 2011 (UTC)

Yes, nok is certainly the word for bird in both Lao and Thai. A kingfisher is nok kraten in Thai (นก กระเต็น)[10] and in Lao they've probably just shortened it (or maybe it was the other way around). Sean.hoyland - talk 10:30, 6 August 2011 (UTC)

Hmmm, that last link gives a script that delivers in Wiktionary, so maybe "นก-เต็น" is the actual word in one or the other language? This seems to be bringing up search hits about the hurricane (e.g. [11]), though often without the hyphen. But searching that in dictionary pulls up นักเต้น (náktên), defined as "dancer". This discussion is a comic (but not so comic) demonstration that - despite some very useful accomplishments - Wikimedia projects still have a serious need for better communication between languages and cultures ... Wnt (talk) 14:17, 6 August 2011 (UTC)

Yes, the Thai press are using นก เต็น (nok ten) as the Thai script transliteration of the Lao ນົກ​ ເຕັນ[12] Sean.hoyland - talk 17:55, 6 August 2011 (UTC)

[From the Language desk] :The Lao spelling appears to be ນົກເຕັນ.[13] This appears to be a name for the kingfisher.[14]. This recent blog post seems to link ນົກເຕັນ with the Common Kingfisher and with the storm (I can't read Lao). Also, if you go to this dictionary, and search for kingfisher in the box marked "Text", you get the entry for ນົກເຕັນ. Unfortunately I don't know how to link to the entry directly.--Cam (talk) 23:55, 6 August 2011 (UTC)

It was Laos who submitted the name to the WMO Typhoon Committee back when the names were devised in the late 1990s assigning it the meaning "bird" HKO, JMA. The Typhoon Committee then selected the JMA to assign the names as it was already their Regional Specialized Meteorological Centre for the region.Jason Rees (talk) 11:07, 7 August 2011 (UTC)

Thanks, all. I have modified Nock-ten (2011) based on the responses and suggest readers check that article- it could use help from the knowledgeable and even lay native angloparlantes. μηδείς (talk) 03:55, 7 August 2011 (UTC)

When in the history of Astronomy could a planet on the far side of the sun be ruled out?

Hello everyone, bit of a conundrum for you. A common speculation in the old sci-fi genre over the years has been a planet orbiting the sun in the same orbital plane as the jolly old Earth but exactly opposite us, so it was always concealed behind the Sun. I was wondering is any of you fine chaps could tell me when such an idea could be definitively proven to be merely a fancy. Not being too up on the old star-gazing routine I'm a bit stumped! I would imagine it could perhaps either been when our understanding of the solar system and our ability to see the effects of a heavenly body's gravitational field on other heavenly bodies was mastered. Alternatively perhaps when those very clever chaps started launching those space probes and the telemetry showed no such place.

Can any of you fine fellows help an old duffer out here? It's a bit hard on the old noggin don't you know. Chin chin! Quintessential British Gentleman (talk) 18:42, 5 August 2011 (UTC)

Yeah, you basically answered it yourself. We'd see such a planet's gravitational effect on other astronomical bodies (Neptune, for example, was expected to exist before we actually observed it...sort of). You might be interested in 2010 TK7, an asteroid that shares Earth's orbit. --Goodbye Galaxy (talk) 19:24, 5 August 2011 (UTC)

Right... but that wasn't your question! Whoops. If I had to guess, I'd say around late 1700s to mid 1800s, but I'm not entirely sure. --Goodbye Galaxy (talk) 19:27, 5 August 2011 (UTC)

If it was a small planet, like Mercury or smaller, it could hide longer then another earth sized planet could, but at some point, the IAU would take away the planet status. Googlemeister (talk) 20:23, 5 August 2011 (UTC)

A so-called counter-Earth would have been known since antiquity, since it would periodically be visible from Earth. First, Earth's orbit is elliptical and not circular, so a planet that was following the same path about the Sun would 'gain' on us when it was close to the Sun, and fall behind when Earth was close to the Sun. (This problem could be avoided if the counter-Earth were in a symmetrical orbit.) The second problem is that the Sun's position is perturbed by the other planets (especially Jupiter) and so wiggles back and forth; depending on where the counter-Earth was in its orbit, it would periodically peek out from behind the displaced Sun.

Leaving aside those issues, a planet of Earth's mass sharing our orbit wouldn't be dynamically stable. (Or, alternatively, our orbit wouldn't be stable.) Small perturbations (caused, for example, by the other planets) would lead to exponentially growing imbalances in the forces on the counter-Earth, relatively rapidly dragging it out from behind the Sun. The mathematics governing Lagrange points (a counter-Earth would be at L₃) showed up in the eighteenth century; presumably a capable astrophysicist of that era would have been able to determine that no stable counter-Earth orbit could exist. TenOfAllTrades(talk) 20:51, 5 August 2011 (UTC)

The point that any sufficiently large "counter-Earth" would be periodically visible, would have followed from the studies of Kepler in the early 17th century, right? 188.117.30.209 (talk) 08:54, 6 August 2011 (UTC)

If it was small enough and dark enough, we might not know about it even now. Of course, as noted previously, something that small can't really be called a planet. However, the definition of a planet includes it clearing it's orbital path of debris, which is difficult to determine if the path was cleared, but presumably mainly by the Earth. StuRat (talk) 21:28, 5 August 2011 (UTC)

Is Wikipedia auditioning for the part of Colonel Blimp? Cuddlyable3 (talk) 21:45, 5 August 2011 (UTC)

Hmmm, it's true that the center of mass of the Sun and Jupiter is outside the Sun. But wouldn't the Earth and Counter-Earth, being bodies orbiting the sun, follow it on its orbit around its center of mass with Jupiter, thus remaining in line with one another and the Sun? Wnt (talk) 22:54, 5 August 2011 (UTC)

Jupiter's period of rotation is much longer than that of Earth, so they wouldn't be synchronized. Rckrone (talk) 03:09, 6 August 2011 (UTC)

I don't think that matters. If the Sun is (a little bit) revolving around Jupiter, then the Earth should be revolving around Jupiter too, as a "moon" of the Sun when looked at this way. Whenever the Sun is on one side of Jupiter (or the barycenter) the Earth is also. Wnt (talk) 14:22, 6 August 2011 (UTC)

Yeah, you're right. Rckrone (talk) 21:37, 6 August 2011 (UTC)

Do you have a source or link for the Jupiter-Sun barycenter claim, Wnt? μηδείς (talk) 03:40, 6 August 2011 (UTC)

See barycenter for one source (NASA).--Shantavira|^{feed me} 07:52, 6 August 2011 (UTC)

Wow. That's great. I am truly impressed by what one learns from wikipedia, as opposed to those moribund rags like Scientific American and National Geographic. Why had I never heard this before? μηδείς (talk) 03:52, 7 August 2011 (UTC)

Thanks everyone for chipping in. I didn't know about that Counter-Earth article, so essentially even before space probes could have seen the area a counter-earth would've either been visually spotted due to the elliptical nature of earth's orbit or it's existence disproven either mathematically or by lack of observable gravitional effects on other planets, and it's likely that the theory was discredited anytime from the 17th century onwards. Thanks chaps, much appreciated. Keep up the good work. Quintessential British Gentleman (talk) 12:21, 6 August 2011 (UTC)

If the planet only "peeked out" a little from behind the Sun occasionally (which seems improbable - it would more likely wander widely), it would only be potentially visible without the aid of modern-ish instruments during total solar eclipses. However its gravitational perturbations on other planets (like those of Neptune on Uranus which led to Neptune's discovery) would have been obvious to astronomers from Newton onwards, as has been said above.

The concept was used for the locale of the Gor series of SF novels by "John Norman", which was subtitled The Chronicles of Counter-Earth. Norman avoided the problem by having the planet be the home of an advanced alien race, the giant-ant-like "Priest-kings", who used their advanced technology to tweak its motion, keeping Gor always exactly opposite Earth and presumably also adjusting the other planets' perturbations. {The poster formerly known as 87.81.230.195} 90.197.66.72 (talk) 17:44, 6 August 2011 (UTC)

move the world

One of the ancient philosophers, maybe Archimedes, stated that with a large enough lever and a place to stand he could move the world. I have my doubts on that. Given known materials, would it be possible to construct a lever capable of moving the earth a distance of 1 cm if we could assume that a 180 lb Archimedes had a place to stand, and a fixed point where he could use his lever, (we should probably assume that he needs to be capable of moving his lever as well)? My guess would be that even if his lever was a Titanium alloy, the lever would need to be so long that poor Archimedes would just have his lever flex on him rather then lifting the earth, but I am only assuming here. Googlemeister (talk) 20:46, 5 August 2011 (UTC)

Agreed, no real-world material would work. Also note that such a lever would be quite massive, so it's gravitational effect on the Earth might well outweigh any use as a lever. StuRat (talk) 21:30, 5 August 2011 (UTC)

(ec)We can't assume what you ask so it's not our problem. Cuddlyable3 (talk) 21:34, 5 August 2011 (UTC)

It should be noted that you don't need a lever to move the world. Any amount of force will do, for example just jumping up and down. Granted it won't move the Earth by 1 cm. But if you're allowed to start not on the Earth ("a place to stand") then you could theoretically shoot yourself at the Earth with enough energy to change it's orbit by 1 cm, or any amount that you like. Rckrone (talk) 22:39, 5 August 2011 (UTC)

According to my rough calculations, if you can find a material workable enough to shape and rigid enough so as not to bend too much, you can nudge the earth over a bit. The trick is to get enough of the material to create a lever with a length something in the range of 100 to 1000 times the diameter of the observable universe. (Less if you weigh more than 200 kilos and are quite strong.)

As noted these are "rough calculations" so please get input from another person at this desk before starting fabrication. CBHA (talk) 23:46, 5 August 2011 (UTC)

A problem here is that like any object, the Earth's doesn't have a precisely defined momentum and position. The uncertainty in the momentum is actually quite large, it's of order sqrt(M k T) with T the temperature at its surface. This means that it becomes a problem to say that a small amount of momentum, say, of order 10 kg m/s added to the Earth actually changed its orbit. The probability that nothing changed at all will be significant. Count Iblis (talk) 00:35, 6 August 2011 (UTC)

He was correct, but would need a lever approximately 5973600000000000000 kms long, according to my (probably wrong) strokes on the calculator, for a push on the lever of about 10kg. It would need to be a thicker lever the closer it gets to earth so it doesn't collapse under the gravitational effects of bodies in the solar system. The hinge required needs to whitstand the force from said gravity, as well as force from the leverage, the faster he wants to move the earth, the stronger the hinge, foundation and lever need to be. Use the ratio of the 1cm : length of lever, which will be the same ratio as the mass of the earth : force applied to lever's end. He weighs 90kg, but he'd need to be in a 1G environment in his 'place to stand' which would clearly need to move if he is to stand. He needs to move through 5973600000000000000 kms for the earth to move 1cm. Anyone want to check/correct the figure ? Penyulap _talk 13:21, 6 August 2011 (UTC)

Archimedes did not specify a distance. His boast was most cromulent. μηδείς (talk) 03:47, 7 August 2011 (UTC)

Cromulent, although unpractical. Plasmic Physics (talk) 00:05, 8 August 2011 (UTC)

So a meter shove of the lever moves the Earth somewhere around 10^-24 meters? That's like 10^-14 Angstroms, and something like a billionth of the size of a proton? Does that count as moving the Earth, if you can't make any observation that would detect the difference, and it is very strictly a statistical effect? Wnt (talk) 19:25, 8 August 2011 (UTC)

So, your question is, "Does actually moving the Earth actually count as moving the Earth?" You can, of course, be killed by things you are not aware of. Ergo.... μηδείς (talk) 00:49, 9 August 2011 (UTC)

Well, if you "move" the Earth in this manner, and you take a poll of the positions of a billion atomic nuclei... half of them have moved one way, half the other. Maybe on average the number moving one way is 1 greater than the number moving the other. Does that count as "moving" it? Wnt (talk) 05:36, 9 August 2011 (UTC)

Let me paraphrase you: "Well, if you "move" the Earth in this manner, ... does that count as "moving" it?"

Unless you want to argue struthiously that what you personally aren't in a position to observe doesn't exist, the logical form of your question is to question the validity of the proposition A > A. μηδείς (talk) 18:57, 9 August 2011 (UTC)

August 6

I've read that children dislike vegetables because they're bitter?

I don't see it in the vegetable article though. I'm also wondering if cooking vegetables change their bitterness, if any. Thanks. Imagine Reason (talk) 00:14, 6 August 2011 (UTC)

Most vegetables don't have much bitterness. The most widely eaten exception is spinach; chard and other greens are even more bitter. In Asian cuisine bitter melon is commonly used, and it's a lot more bitter. There are many more bitter spices than vegetables. Looie496 (talk) 00:37, 6 August 2011 (UTC)

Possibly relevant: slow acetylator. --Trovatore (talk) 00:44, 6 August 2011 (UTC)

... except it's a redlink; WADHAAOE. I'm shocked. --Trovatore (talk) 00:45, 6 August 2011 (UTC)

There is mention of the concept at Drug metabolism, Pharmacogenetics, N-acetyltransferase 2, Nutritional genomics and a bunch of articles on drugs and other stuff. One of these may be suitable as a redirect target, at least for now. Nil Einne (talk) 11:50, 6 August 2011 (UTC)

Children dislike vegetables because vegetables don't taste as well as sweets, cookies, icecream, cake etc. Count Iblis (talk) 01:06, 6 August 2011 (UTC)

There are other reasons not to like veggies. Some are tough, and cooking can help there. Adding fat, like butter, can also make them "go down easier". Some people also have a genetic tendency to dislike cruciferous vegetables, like broccoli. And, perhaps by bitter you meant "not sweet". In that case, they may like some of the sweeter veggies, like carrots and beets, or adding a sweet salad dressing to the rest. StuRat (talk) 01:08, 6 August 2011 (UTC)

Or just follow Amy Chua's advice. :) .Count Iblis (talk) 01:50, 6 August 2011 (UTC)

I guess you're thinking of supertasters Nil Einne (talk) 11:55, 6 August 2011 (UTC)

Cooking can sweeten onions by caramelizing them, so yes cooking can help sweeten the pot. Still, with kids, sometimes their preferences must be acquired with time, as they get older. For instance, it can be difficult to eat something if one associates it with an illness, pest or an odd sensation. For a while, I would refuse to eat raisins from a box after having found ants in one. Similarly, for a number of years, I would relive being sick whenever I smelled macaroni and cheese. But I eventually realized these aversions were silly and now, like most adults I think, enjoy foods I may have shunned. With any food it helps if its prepared well, especially by a great cook. For instance, care must be taken to not over-cook any veggie into a bland mush (and even uncooked celery or a carrot needs a good dip). Various soups and side dishes are satisfying, but my preference has always been the casseroles my mom made. She mixed veggies such as carrots, beets, spinach, broccoli, and cauliflower with other ingredients such as cheese, chicken, pasta and potatoes. Her rhubarb cobbler is out-of-this world too. --Modocc (talk) 03:25, 6 August 2011 (UTC)

To begin with some subjective opinions, as someone still repulsed by raw onions to this day, I'd say it's not merely a matter of caramelization - maybe it's the breakdown of allicin or related compounds with a strong stench. But as a child I was much more sensitive to such scents - even smelling a bit of it in the tiny bits of onions in commercial spaghetti sauce, where I'd think every last molecule had been decomposed.

But my reaction to almonds was much, much weirder. As a child I was incredibly sensitive to a terrible, oily smell in them - something like a cigarette which to merely touch it for a moment left a reek on my fingers that took soap and hot water and scrubbing to clean off. But when I was around 15 the scent became much less pronounced, so much so that within a year or two I could actually eat a few experimentally. Within a few years after that, the scent became so weak that they became an acceptable snack, and after a decade or two the scent was truly undetectable. I'm thinking that there must be odorant receptors which are activated by promoters that shut off in adulthood. Wnt (talk) 05:01, 6 August 2011 (UTC)

But the next question is "Why ?". What evolutionary path would lead to almonds being objectionable to some children, but not to adults ? Are they actually harmful to some children, perhaps due to the cyanides present in small quantities ? Maybe those chemical stunt some growth process at low levels ? StuRat (talk) 05:21, 6 August 2011 (UTC)

I wonder if diversity in food preferences actually represents an evolution of the scientific method. If some people in a tribe eat a food and others don't, people might recognize that the food is responsible... Wnt (talk) 13:43, 6 August 2011 (UTC)

Children are know to try a lot of things, and hence are at higher risk from dangerous foodstuff. Adults will have learned to be more discriminating. Also, once you're past 25, you're supposed to have done your bit for the propagation of the species, of course, so evolution wouldn't give a hoot if you jumped off a cliff ;-). --Stephan Schulz (talk) 08:50, 6 August 2011 (UTC)

If you jumped off a cliff at 25, your 5 children would starve. :(

You should be 45 at least before you jump off a cliff I think. Rckrone (talk) 22:24, 6 August 2011 (UTC)

You should be well past 70, and have walked your children through all the stages of parenting, long before you consider tetherless bungee jumping. μηδείς (talk) 03:42, 7 August 2011 (UTC)

We do have an article, perhaps not that useful, on Selective eating disorder Nil Einne (talk) 11:52, 6 August 2011 (UTC)

Humans have evolved as Omnivores and thrive on a balanced diet of plants and animals. However catching animals is harder than picking plants because plants don't run away. To compensate for the difference and favour a balanced diet, instinct gives a greater pleasure reward from eating animal products than vegetables. Cuddlyable3 (talk) 13:16, 6 August 2011 (UTC)

Vegetables are not bitter, unless you are not cooking them properly or are a supertaster. I had no problems eating vegetables when I was a kid. I understand that in the US almost everything has sugar added to it: perhaps you are describing the rare taste of something sugar-free. Update: when years ago I used to take sugar with my tea, then tea without sugar would taste unpleasant, "bitter". But after very gradually over years reducing the sugar in my tea to nothing, sugarless tea does not taste bitter at all, but nice. Now I much prefer sugarless tea. 92.28.252.178 (talk) 15:36, 6 August 2011 (UTC)

Alkaloid toxins are generally bitter. And it certainly doesn't help a poisonous plant to taste good and be eaten up before it kills you. μηδείς (talk) 03:42, 7 August 2011 (UTC)

I'm surprised that no other old fart has yet responded with something along the lines of "The kids of today have too much choice. When I was young we ate what was put in front of us or went without." It was certainly true in my case, and I suspect for most of human history for most people. Having a choice of foods at every meal, and in between meals, is the unnatural thing here. Maybe we should get deeper into this issue of actually having this choice. It would have been rare in the past, and maybe there was a point to our preferences when it occured. HiLo48 (talk) 03:49, 7 August 2011 (UTC)

cosmic strings

what are cosmic strings? — Preceding unsigned comment added by 175.110.242.217 (talk) 02:46, 6 August 2011 (UTC)

They are topological defects of space-time. As you can see stated on the first line of the article cosmic strings. Hair whorls are familiar examples of a topological defects. Dauto (talk) 03:16, 6 August 2011 (UTC)

pretzel making

What are the byproducts after baking of submerging pretzel dough in sodium hydroxide (or potassium hydroxide) to produce a glaze? --DeeperQA (talk) 10:45, 6 August 2011 (UTC)

Water. See Neutralization (chemistry). Plasmic Physics (talk) 12:18, 6 August 2011 (UTC)

The above may be true for lye as a reagent, but it would also be good to consider its role as a catalyst. It should be clear from the formation of the crust that there's been substantial chemical change in the dough, but I didn't find much of interest on NCBI (only PMID 14733520, which is more about what the lye prevents by neutralizing acid). And nothing on Google. But there's a lot of information out there - there are probably specialized food resources that I don't know about. Wnt (talk) 14:37, 6 August 2011 (UTC)

The Maillard reaction, one of the reactions involved in the browning process, is affected by pH (enhanced under alkaline conditions). I assume other related reactions are affected as well (not sure which other specific ones are accelerated or slowed). DMacks (talk) 16:35, 6 August 2011 (UTC)

Caramelization is also affected by pH (and also enhanced under alkaline conditions)--I just added that content (with ref:) to its article. DMacks (talk) 17:48, 6 August 2011 (UTC)

space/time, energy/matter

Is it safe to say that space/time is the only place energy/matter is located? --DeeperQA (talk) 10:50, 6 August 2011 (UTC)

Yes. Plasmic Physics (talk) 12:15, 6 August 2011 (UTC)

Better to say that it's the only place that we know about. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:46, 7 August 2011 (UTC)

That can be said about any scientific extrapolation. Plasmic Physics (talk) 23:15, 7 August 2011 (UTC)

Bingo! ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:24, 7 August 2011 (UTC)

gravity

Is there any time or place where gravity does not or did not or will not exist? --DeeperQA (talk) 10:52, 6 August 2011 (UTC)

Depends what you mean by "exist". Does zero gravity answer your question?--Shantavira|^{feed me} 11:08, 6 August 2011 (UTC)

No, gravity fields extend indefinitely into space-time, like electric and magnetic fields. Plasmic Physics (talk) 12:21, 6 August 2011 (UTC)

Yes, see Lagrangian point. Cuddlyable3 (talk) 13:05, 6 August 2011 (UTC)

Isn't there plenty of gravity at Lagrangian points, but just pulling in the right way to keep in orbital sync? 81.159.105.227 (talk) 13:34, 6 August 2011 (UTC)

Yes, you are right. Dauto (talk) 14:35, 6 August 2011 (UTC)

Yes. If there was no gravity, the object would fly off into deep space. Objects at L-points are still in orbit around the primary and any orbit needs gravity to close it. --Tango (talk) 21:36, 6 August 2011 (UTC)

No, gravity is still active at a langranian point, it is just a metastable position. Plasmic Physics (talk) 19:26, 6 August 2011 (UTC)

If you were sitting between two galaxies, wouldn't the gravitional pull there be pretty much negligible? ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:58, 7 August 2011 (UTC)

You'd be at a tipping point where you need just the right push to be pulled to either side. That's besides the point thought, there is still gravity. Plasmic Physics (talk) 23:11, 7 August 2011 (UTC)

Sure. What I'm getting at is whether the "pull" of a given object (the sun, for example) is just as strong several light years away as it is where we are now. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:14, 7 August 2011 (UTC)

Obviously not, though gravity is still present, just weaker. Plasmic Physics (talk) 23:39, 7 August 2011 (UTC)

Is the "strength" of a gravitational field, an inverse-square relation? ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:47, 8 August 2011 (UTC)

Yes. And electromagnetism is inverse-cube. --Goodbye Galaxy (talk) 14:16, 8 August 2011 (UTC)

Power outages

Hi. Could recent power outages in the local area been caused by solar geomagnetic storms that hit the Earth? Do those typically cause outages lasting on the order of 1 minute? Is it usually possible to trace or identify the source or otherwise an exact cause of a local outage? Thanks. ~AH1 ^(discuss!) 12:28, 6 August 2011 (UTC)

I doubt it. The geomagnetic induced currents are not that large that they would directly cause problems. You would need circuits of huge areas to get large induced currents. What can happen is that such currents cause tranformer cores to get magnetized, and then the power transmission from the powerplant to the grid becomes less efficient. It is this dissipatated power originating from the powerplant that can destroy transformers. Count Iblis (talk) 17:00, 6 August 2011 (UTC)

What do you mean by "recent"? Our article on geomagnetic storms affirms that they can indeed cause outages, and there was speculation that the storm that struck yesterday/today might be strong enough to have effects, but a quick scan of news doesn't show any specific reports. Looie496 (talk) 20:28, 6 August 2011 (UTC)

It's doubtful that news organizations would report on strings of localized power outages lasting on the order of seconds to minutes without severe effects. ~AH1 ^(discuss!) 23:43, 7 August 2011 (UTC)

distinction between coordinate covalent bond and covalent bond

why does the distinction between coordinate covalent bond and covalent bond vanishes after bond formation in NH4+ H3O+ and CH3NH3+? — Preceding unsigned comment added by 175.110.242.217 (talk) 16:48, 6 August 2011 (UTC)

The "coordinate" part of the Coordinate covalent bond name simply refers to where the electrons of the bond came from before the bond exited. Once the bond forms, there is no longer any evidence of this aspect of the bond. You can point to a bond in a drawing and say "this one's electrons came from that atom", but that is not a property of the molecule itself in real life. The electrons are not individual particles that are specifically part of a one specific bond in the molecule. DMacks (talk) 17:08, 6 August 2011 (UTC)

Indeed, electrons have no memory about where they came from. More importantly the same "bond" could be "formed" in different ways, and get the same result. Describing a bond as a "coordinate covalent" bond really just implies that the bond formed via a Lewis acid-base reaction whereby the bond is formed as a 2-electron filled orbital in one atom merges with an empty orbital in another atom to form a new filled bonding orbital and unfilled antibonding orbital. The other method of bond formation occurs when two 1-electron half-filled orbitals form the bonding/antibonding pair of molecular orbitals. Once the result is done, however, the bonds behave the same whether they formed via the former method or the latter. --Jayron32 17:50, 6 August 2011 (UTC)

How much (embedded) energy is needed to build different kind of power plants?

How much (embedded) energy is needed to build different kind of power plants? And with embedded energy, I mean the energy used by machines of different kinds: electrical sources, fossil fuels as well as renewable sources, etc. And with machines I mean the machines involved in the creation of the power plant, that is: transportation of components to the place, the production elsewhere of different components needed for the construction, and perhaps also the extraction of the raw material needed for the production of components. So, I would like to know how much energy that is needed to build, for example a nuclear plant or a wind turbine, and then I also wonder how long time it would take for the different kinds of power plants to create (transform) the same amount of energy as it took to construct the plant? I know that this is a hard thing to answer, but it would be very interesting if someone could make at least some simple calculations on it. //moralist 19:32, 6 August 2011 (UTC)

At the risk of angering many energy "activists" - there is absolutely no meaningful way to define "embedded energy" without incurring a wild goose chase of infinite recursion. It is for this reason that reliable sources, such as the United States Department of Energy and the Energy Information Administration, make essentially no reference to this parameter. You can verify this for yourself using your favorite web search utility or by perusing the websites of such organizations. I highly recommend reading their reports, incliding the EIA's short- and long-term energy outlooks, to gain perspective into this issue. This is not to say that embedded energy doesn't "exist" - of course energy is used to build new energy production facilities; it's just that quantifying that energy is more a game of politics than of science. You may find similarities between embedded energy and the energy returned on energy invested - another similar economic parameter typically applied to fossil fuel extraction. Nimur (talk) 20:48, 6 August 2011 (UTC)

Here is a good article: "How can we compare or add up our energy consumption?" This article explores the difficulties of adding different types of energy used in different scenarios, and presents the methods used by the United States for statistical purposes. Nimur (talk) 20:58, 6 August 2011 (UTC)

From reading that article it seems trivially easy. Its only "difficult" because they don't use metric. 92.28.249.101 (talk) 23:13, 6 August 2011 (UTC)

Here are some more resources for you to read: Energy Efficiency, which outlines a statistic called the "Primary Energy Conversion Factor" and is based on real data, and Interactions in the National Energy Modeling System, which expresses market and economic interactions with various primary energy conversion factors via a sophisticated computer model. Nimur (talk) 21:16, 6 August 2011 (UTC)

Well, actually, in a free market where all real costs, including those of insurance, waste disposal, and other hidden variables are rationally assigned--rather than assuming "someone" will clean it up, you can make such calculations as best is possible. The problem is incurred when free markets in immediate costs are mixed with the assumption that someone else, usually the tax payer, will deal with the costs of things like long term toxic waste disposal, birds killed by noisy windmills, dam collapse, or poorly designed and managed nuclear plants in quake zones and tsunami shadows. There is no such thing as absolute knowledge. But if you disabuse private investors of the notion that the state will clean up in the case of emergency and require rational preparation to address all costs, the free market will price in such costs for you. Sorry if that provides no specific answer in any concrete case. μηδείς (talk) 03:21, 7 August 2011 (UTC)

There is this technical resource, George Reisman's Austrian economics-treatise Capitalism, available for pdf format download at capitalism.net and for hardcover purchase at Amazon. μηδείς (talk) 03:35, 7 August 2011 (UTC)

To paraphrase what I said the last time this came up: the free market won't insure against large uncertain future expenses because it's too risky. Insurance companies want certainty like everyone else, and they do that by insuring against frequent, small (at the scale of the insurance company) losses. This limitation of the market has nothing to do with whether it's a good idea to build nuclear plants or not. It probably is a good idea, since coal and petroleum are much worse, and nothing else can supply the modern world's energy needs. When there's something that needs to be done but the free market won't do it, governments step in; that's what they're for. I know there are people who believe that the market does everything perfectly and governments should be abolished, but those people are wrong, just like the people who think that homeopathy works, etc. This is the science desk. -- BenRG (talk) 04:30, 7 August 2011 (UTC)

MOX UK

The UK is closing a MOX plant that's only a few years old and cost over a billion to build because there has been insufficient demand for its product, particularly after the Japanese tsunami.

But why is there is talk of building another MOX plant on the same site as the closed/bulldozed one that will cost six billion?

I understand that this is a way to get rid of a large plutonium stockpile, but would it not be cheaper to design future UK nuclear reactors to use the specification of MOX fuel that the 'old' plant produced? 92.28.249.101 (talk) 23:09, 6 August 2011 (UTC)

I take it (from this article) that the closing plant is at Sellafield. As for why... I'm not informed enough on the issues to be totally sure, but it does look an awful lot like a boondoggle. It doesn't look like experts think there is really a market for a new MOX plant. As for why you wouldn't just make reactors that could take old MOX fuel, the issue is likely that the new generation of reactors have inherently different fuel requirements. Reactor fuel requirements are often quite specific if the reactor is meant to be profitable — the margins of profit are not huge. With research reactors (because profit is not a big issue) you can often re-engineer them to take different types of fuel (e.g. changing a HEU reactor to a LEU one) but that usually changes the power output quite a bit and requires extensive design changes. So it's not an easy change. As to why they didn't design it in the first place, the tautological answer is probably "because it wasn't a good idea to do so, probably for economic reasons," but that's not a very interesting explanation.

Anyway, it is a very good question, and it seems a lot of experts and citizens are rightfully asking. The official answer given ("Don't worry, there will be a market! Plus: jobs!") is not very compelling on the face of it. It's really, really unclear right now what the future of the nuclear industry is. For awhile it looked like there would be a "Renaissance" (Nuclear renaissance) in nuclear power, but after Fukushima it is a lot more problematic. --Mr.98 (talk) 00:19, 7 August 2011 (UTC)

The Guardian article linked to above says that the government's talk of building another MOX plant was just a red-herring so that the plutonium stockpile would not be recorded as a massive liability (rather than an asset) on the government balance sheet. Why cannot politicians be honest for a change - we're not in Italy. I hope the putonium can be used up for power generation rather than being a dangerous stockpile for many centuries. 92.24.133.68 (talk) 12:55, 7 August 2011 (UTC)

It seems the problem is many in government are hoping the same thing, but experts believe the truth isn't so rosy Nil Einne (talk) 19:15, 7 August 2011 (UTC)

August 7

Reactive Oxygen Metabolites vs Reactive Oxygen Species

Is there a difference between 'Reactive Oxygen Metabolites' and 'Reactive Oxygen Species'?

The difference between the two is that Reactive Oxygen Metabolites refers specifically to the Reactive Oxygen Species produced as byproducts of metabolism. Reactive Oxygen Species on the other hand, refers to both metabolites and synthetic ROS. Hydrogen peroxide for example, is a ROS that is usually familiar to us in their synthetically (or otherwise naturally produced, but not by living processes) created form (i.e. not metabolites), but which are also produced naturally by organisms as [waste] products. Both can be called ROS, but only the latter is ROM.-- Obsidi♠n Soul 15:46, 8 August 2011 (UTC)

Do people actually sleeps like this?

See image on this link. [15]

Is this real or is it a joke? Ohanian (talk) 10:26, 7 August 2011 (UTC)

It might well be a joke (tempting to wake her up...) but it could be real. After all, fairly often I use a position with one foot up in the air balanced against a knee in a tetrahedron. As anyone who's had a stiff neck should know, sleep paralysis seems to involve actively maintaining muscular tension, not just flopping lifelessly. Wnt (talk) 11:37, 7 August 2011 (UTC)

I can state with absolute factual knowledge.. It's not a joke. When I was a child I quite often slept in exactly that position. I can't say why, my body just automatically sought that position for comfort.190.56.115.12 (talk) 14:32, 7 August 2011 (UTC)

I can also confirm it's not a joke. My daughter often sleeps in this position, and so did her grandmother as a child. But the habit appears to have jumped a generation. Hans Adler 15:10, 7 August 2011 (UTC)

I've seen infants sleeping in that position, but not adults. But anything's possible. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:42, 7 August 2011 (UTC)

Is there a name for that sleeping position? Bus stop (talk) 18:47, 7 August 2011 (UTC)

My 2.5-year old son sleeps exactly like that. My wife and I often comment on how uncomfortable it looks, but this is one of those personal preference/subjective things. If it works, who are we to care... --Jayron32 18:58, 7 August 2011 (UTC)

I was thinking the most obvious name for it would be the "bottoms up" position. Googling [sleeping positions], the general stomach-down position seems to be called "freefall". I don't know if that term would apply to this particular face-down position. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:00, 7 August 2011 (UTC)

Of course, wikipedia has articles on everything. I can't yet find a name for this position, but I did find Human positions and a spinoff article titled Sleeping positions and the category Category:Human body positions. --Jayron32 19:03, 7 August 2011 (UTC)

It's a completely different context, but I did fine the article Kowtow which is almost the exact same body position. --Jayron32 19:05, 7 August 2011 (UTC)

Photographs of sleeping babies. Bus stop (talk) 19:07, 7 August 2011 (UTC)

Cute, but every one of those pictures looks "posed" by someone other than the sleeper. I'm not sure any of them represents a natural "sleeping" position the child would have assumed if left to its own devices. --Jayron32 19:12, 7 August 2011 (UTC)

They do at that, but I have seen infants sleeping in that "bottoms up" position. One thing to keep in mind is that their legs are very short compared with adults, which is why I find it hard to believe that would be a comfortable position for an adult. But it takes all kinds. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:53, 7 August 2011 (UTC)

The Muslim prayer position is also similar to this. ~AH1 ^(discuss!) 23:40, 7 August 2011 (UTC)

Lordosis behavior. Cuddlyable3 (talk) 07:20, 8 August 2011 (UTC)

I'm just speculating, but that looks like a very safe position to sleep in. Your most delicate areas (face, abdomen, groin) are all protected. It's not dissimilar to the foetal position, but it is probably easier to sleep like that than in the foetal position (I find I need to hold my knees in place with my arms if I'm going to stay in the foetal position). --Tango (talk) 14:34, 8 August 2011 (UTC)

CHOCK

What is the back emf produced across the electrical ballast at the time when the supply to the tube light is OFF.vsnkumar (talk) 11:02, 7 August 2011 (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.

To calculate the back-emf in an inductor, you need to to know the voltage across the inductor, its inductance, and the resistance of any discharge path. CS Miller (talk) 12:00, 7 August 2011 (UTC)

Chicken lays eggs with double yolks

I have 6 chickens and one of the chickens lays a large egg which has two yolks each time she lays. My question is: If I were to have a rooster around and her eggs were fertile, would there be any possibility that two chicks would come from her egg(twins)? I'm new at raising chickens. — Preceding unsigned comment added by User:TerrDA (talk • contribs)

Theoretically yes. But I have asked around and it seems twin chicks from one egg is not recorded, probably because there is not room in the egg for two embryos to mature. Cuddlyable3 (talk) 18:20, 7 August 2011 (UTC)

Take a look here. Twin chicks from a single egg has happened, but only with human intervention. When I saw double yolked eggs as a kid, I always assumed that they'd come out as Siamese twins if they were allowed to hatch. --Kurt Shaped Box (talk) 18:33, 7 August 2011 (UTC)

Speed of light

why cant we travel faster than the speed of light?why does laws of physics prevent us? — Preceding unsigned comment added by 175.110.242.217 (talk • contribs)

Have you read the Speed of light article's section about upper limit on speeds? -- JSBillings 18:11, 7 August 2011 (UTC)

(ec):Wikipedia has an article about the Speed of light but you may like to read this article first. Cuddlyable3 (talk) 18:12, 7 August 2011 (UTC)

See also superluminal communication. ~AH1 ^(discuss!) 23:33, 7 August 2011 (UTC)

Here are the fastest speeds by a man compared to the speed of light c

• Sprinter 10.35 m/s = c / 10⁷
• Plane SR-71 "Blackbird" 600 m/s = 2c / 10⁶
• You and me on Earth going around the Sun 30 000 m/s = c / 10⁴
• You and me and the local group of galaxies going towards the constellation Hydra 600 000 m/s = 2c / 10³
• Speed of light 299 792 458 m/s = c

Cuddlyable3 (talk) 07:39, 8 August 2011 (UTC)

Tea "espresso"

Lately I prefer tea to coffee, but traditionally I drank espresso, and when drinking tea I like it to be very strong, bitter, and highly caffeinated. I use several teaspoons (or sachets) of black tea per cup of water, and let it steep for ages. Still I would prefer something more concentrated. Is there a way to brew tea that will yield a beverage comparable to espresso? I don't hope to replicate the texture, because tea is much less oily than coffee, but I would at least like to have something equally caffeinated, and which can be drunk in a very small quantity. LANTZY^TALK 18:01, 7 August 2011 (UTC)

Iranian Persian style tea is so strong that they consume it while holding a sugar cube in the mouth to sweeten it. I believe they usually brew with a samovar but I'm not sure what the exact process is. Beeblebrox (talk) 18:39, 7 August 2011 (UTC)

If you want stronger tea (this is actually true for coffee as well, since they both are produced from steeping), you'll just want to use more tea when you steep. There is somewhat of a misconception that steeping longer will make it stronger; however longer steeping times tends to extract a higher percentage of undesirable flavor compounds, which can actually make the tea less "tea like". Of course, tastes vary, but if you want a stronger "tea" flavor, you'll want to use more tea when you steep it; don't alter the standard steeping time, just use more. --Jayron32 18:46, 7 August 2011 (UTC)

You probably know this already, but the variety of tea makes a big difference - Assam typically gives a much darker and stronger brew than Darjeeling for example, though both are black teas. AndrewWTaylor (talk) 20:44, 7 August 2011 (UTC)

If you want maximal concentration, boil it down. That's what the Tibetans do to make their famous (or infamous) butter tea: they dump a mass of tea leaves into boiling water and boil it for half a day. Looie496 (talk) 23:39, 7 August 2011 (UTC)

Good point. I considered this, but it turned out not to be necessary. My experiment: I steeped 200 grams of Assam tea ("Irish breakfast") in c. 800 ml of water (in a French press), and ended up with about 500 ml of opaque red-brown liquid. Texturally it resembles espresso, even having a pale creamy foam on top, and like espresso it leaves a distinct residue behind in the cup. The taste is astringent, herbal, and cleaner than espresso, leaving less of an aftertaste. If you drink espresso for the caffeine, this will do the trick just as well. I'm still curious as to whether I could produce the same thing more efficiently in an espresso maker. Actually, I'm surprised it hasn't been attempted before. People like espresso, people like tea... so why not tea-spresso? LANTZY^TALK 02:55, 8 August 2011 (UTC)

I think you are only drinking it for the caffeine, since "stewing" it as we call it over here makes it taste very bitter due to the tannins etc leaching out of the tea leraves. Personally I prefer tea that was been in contact with tea leaves for just a few seconds, as that gives the best flavour as the tannins do not have time to leave. Green tea is said to have more caffeine than black tea. Perhaps you could try drinking it Japanese style. 92.28.240.88 (talk) 10:25, 8 August 2011 (UTC)

Stewed tea certainly gives you a buzz (by the way, if you're drinking it for caffeine, quantity often helps: at uni I went through a phase of using a ginormous pint-and-a-bit mug) and the taste isn't actually too unpleasant. Best stop shy of chifir though. Brammers (talk/c) 15:13, 8 August 2011 (UTC)

Oh, my, so that's the stuff the Russians in the lab made... I only remembered them calling it "chai". They were very finicky about getting just the right kind of black Indian tea for it. I think definitely if the DEA had been around to taste that stuff in the Middle Ages, tea would be selling for $300 an ounce today and every other person in America would be drinking it. Wnt (talk) 18:32, 8 August 2011 (UTC)

Coca tea is also quite strong. Count Iblis (talk) 20:21, 8 August 2011 (UTC)

I think so much caffeine is unhealthy and bad for you. Does the OP have trouble sleeping? If you insist, despite the bad health effects, on consuming high quantities of caffeine, then why not just take caffeine tablets? Then you could drink normal tea and enjoy its taste. 92.24.191.250 (talk) 20:57, 8 August 2011 (UTC)

Mitochondrial Inheritance

Hello. If sperm mitochondria degrade in the egg cytoplasm after fertilization, why can the egg mitochondria survive? Thanks in advance. --Mayfare (talk) 19:00, 7 August 2011 (UTC)

Our article on Mitochondrial DNA actually addresses this very question, specifically the section on Female inheritance. Vespine (talk) 02:30, 8 August 2011 (UTC)

Language++

In a recent discussion about the "invention" of language (presumably THE milestone of human cerebral(?) / social / cultural development) we - a group of midly intoxicated rambling geezers of nascent senility - wondered idly:
Have scientists (from biologists to futurologists to SF writers) speculated on theoretical evolutionary / cognitive "quantum leaps" which may be as revolutionary as the development of oral and written language?
I am aware that some scientists expect genetic enhancement / nanotechnology / cerebral to digital interfaces and even consider the possibility of a "fully digitalised" non-corporeal HS as a possible future. I am, however, not so much interested in "engineered" evolution and apologize for a border-line crystal gazing question. Thank you for any ideas! --Cookatoo.ergo.ZooM (talk) 21:11, 7 August 2011 (UTC)

R. Daneel Olivaw (especially his later appearences in fiction) may provide some interesting ideas for you. --Jayron32 23:37, 7 August 2011 (UTC)

Wikipedia also has the article Infomorph (a term I had never heard before) which I tripped over while remembering the character "The Dixie Flatline" from Neuromancer, which also has some advanced ideas about consciousness. Also, John Scalzi's "Old Man's War" series has some interesting stuff on transferance of consciousness and soul from one body to another. --Jayron32 01:22, 8 August 2011 (UTC)

The article Origin of language speculates on the onset in prehistory of human spoken language but the pivotal development was written language. This enabled dissemination of information and its flow from each generation to the next, and the consolidation and identification of competing societies by their diverse textual languages. Cuddlyable3 (talk) 07:53, 8 August 2011 (UTC)

There is some debate, however, among scholars as to the importance of oral tradition in terms of preservation of knowledge. Pre-literate societies still managed to do some pretty amazing stuff, technologically speaking, without formal written language. The Incas, for example, had no written representation of their spoken language (the closest they had was a knotted string which they used as a form of accounting), and yet were able to build a highly developed civilization with some pretty advanced engineering. Certainly, written language is very important, but there are some counterexamples where some rather advanced civilizations got along without it. --Jayron32 13:28, 8 August 2011 (UTC)

See Hippocampal prosthesis. Provided sufficient bandwidth of communication, this is what you're looking for. For further details see Mark of the Beast and Revelation of John. Wnt (talk) 13:58, 8 August 2011 (UTC)

Urk. The "hippocampal prosthesis" is pseudoscience, in my opinion. Looie496 (talk) 21:49, 8 August 2011 (UTC)

Written language was a lot harder from an evolutionary perspective than spoken language. It's important to see them as quite different things. The idea of written language has only been independently invented a few times in human history, as far as we can tell, whereas oral traditions seem to spring up spontaneously. --Mr.98 (talk) 15:22, 8 August 2011 (UTC)

nucleon model

When you feed all of the known and speculated parameters of a nucleon into a supercomputer what sort of model does the supercomputer predict? --DeeperQA (talk) 23:36, 7 August 2011 (UTC)

What do you mean "feed" and "supercomputer". I am thoroughly confused about what you are asking. The computer doesn't predict anything. It predicts what humans tell it that it will. If you want to know what we currently know about nucleons, read the article nucleon. --Jayron32 23:39, 7 August 2011 (UTC)

It is the same sort of process used to model or predict future weather albeit for only a short distance in time. We feed the computer data from weather patterns gathered over long periods of time and ask it to find parameters. Then we feed the parameters back into the computer and see what model the computer comes up with similar to performing Fourier analysis on music to derive the coefficients of each harmonic which we can feed back as is or alter the value of each harmonic independently to see what sort of music we might get back. In the case of the nucleon we are asking the computer to find the model that fits all of the parameters best. --DeeperQA (talk) 00:03, 8 August 2011 (UTC)

Yes, but the difference is, we don't know (without the computer models) what the weather is going to be like next week. We do, however, know what the nucleon is going to look like next week. Now, pretty much all of what we know about the nucleon is based on data from complex computer models, so if your question is "what do existing computer models tell us that nucleons behave like" then the answer is "see nucleon". If the question is "how do computers help us probe the behavior of nucleons" then you'll want to research more into the fields of Computational chemistry and Computational physics. --Jayron32 00:14, 8 August 2011 (UTC)

No, my question is strictly one relating to geometry. --DeeperQA (talk) 00:27, 8 August 2011 (UTC)

In that case, we know next to nothing about the internal geometry of nucleons. The best work in this area is in the field of Lattice QCD, so you may want to look there for your research. --Jayron32 00:29, 8 August 2011 (UTC)

Taking a step back: Computers do not magically give you a model. In addition to the data, you also have to feed it with a model (in the form of a computer program), based on a physical theory and some assumptions regarding geometry etc. The model may contain free parameters (e.g. coupling constants), in which case you can use the computer to determine the parameter values (in the context of that model) which give the best fit to the data. Alternatively, if you know the values of the parameters, then you can fix them and predict a future state of the system that you are trying to describe. --Wrongfilter (talk) 10:53, 8 August 2011 (UTC)

As I indicated that is true for harmonic coefficients which are known and for neural networks which have weights that are known. But harmonic analysis has the ability to find harmonic coefficients while neural networks have the ability to find weights while in training mode that can be used as a model on which to explore possibilities not found in the training data. --DeeperQA (talk) 15:04, 8 August 2011 (UTC)

shortest inverval of time

What is the shortest interval of time in which the Large Hadron Collider (LHC) can detect a product of the collision of two protons? --DeeperQA (talk) 23:55, 7 August 2011 (UTC)

The products of the reaction fly away from the collision and are detected centimeters to meters away after picoseconds to nanoseconds have passed. The equipment typically can resolve an event with roughly nanosecond timing. Is that what you wanted to know? Dragons flight (talk) 06:55, 8 August 2011 (UTC)

Are you saying that the product paths (line of dots) have dots that are spaced at intervals of one nanosecond? If so then yeas. --DeeperQA (talk) 13:47, 8 August 2011 (UTC)

If so then what are that chances of capturing a par tile that last for less than a nanosecond? --DeeperQA (talk) 15:40, 8 August 2011 (UTC)

Manual study off line of the products of a collision will take much longer. Cuddlyable3 (talk) 08:42, 8 August 2011 (UTC)

August 8

Shortest division of time

Can time be infinity divided? --DeeperQA (talk) 00:25, 8 August 2011 (UTC)

Yes. --Jayron32 00:32, 8 August 2011 (UTC)

Any time interval less than the Planck time is theoretically unmeasurable. (In practice, we cannot get anywhere close to measuring intervals that small.) I am not sure whether it is really agreed upon whether there is a "real" quantum of time or not, or if it is "just" a measurement problem. If there is a quanta of time, the answer is "no". If there is not, the answer is "in some sort of metaphysical sense, maybe, but practically, no." --Mr.98 (talk) 00:50, 8 August 2011 (UTC)

As a measurement problem it sounds a lot like the function of y=arctan(x) where no matter how large x becomes, y will never attain a value of one with the practical problem being that of measurement where the difference between 1 and y is not measurable although y is still separate from one. --DeeperQA (talk) 01:15, 8 August 2011 (UTC)

No Jayron32. One of the assumptions of Zeno used in his dichotomy paradox is that between any two different points in time there is always another point. Without this assumption there are only a finite number of intervals between two points, hence there is no infinite sequence of movements, and the paradox is resolved. Cuddlyable3 (talk) 08:51, 8 August 2011 (UTC)

Well, the dichotomy paradox is resolved anyway (the infinite geometric series converges for r = 1/2), so that's no argument. Classical mechanics and standard quantum theory use the real numbers to represent time mathematically, hence time can be divided infinitely in the framework of these theories. The question is: are these theories useful models for reality for very short time intervals? Answer: no. We expect quantum theory to break down at around the Planck scale, i.e. for time intervals on the order of the Planck time, at which point we need a new theory (which reduces to quantum theory at longer time intervals) to describe reality at these scales. Physicists are working on finding such a theory but they are far from achieving that goal. Ideas often assume that time is in some way discretized with a unit on the order of the Planck time or shorter, but at the moment those are more or less speculations. So the answer to DeeperQA's question is: We don't know. --Wrongfilter (talk) 10:46, 8 August 2011 (UTC)

DeeperQA mentions the arctan function that is relevant when displacement s is a function of time t i.e. s = f( t ) . We may take the arctan of the change in displacement during an interval of time. Now suppose we keep reducing the time interval. At the limit where both the time interval and the corresponding displacement are both infinitesimal, the arctan value is defined as ds/dt . This is an operation in Differential calculus. Cuddlyable3 (talk) 11:33, 8 August 2011 (UTC)

DeeperQA brought up the arctan as an example of asymptotic behaviour if I'm not much mistaken. --Wrongfilter (talk) 12:56, 8 August 2011 (UTC)

Rather than one I meant π/2 but in any event even at x=infinity y still does not and cannot reach π/2, although for the purposes of the Calculus we treat it as though it does. --DeeperQA (talk) 13:42, 8 August 2011 (UTC)

You might also look over the time article. It is not a straightforward thing and there are a lot of very unusual ideas about it. Treating it as some sort of straightforward quantity is not a correct physical way to think about it. At some level if one wants to talk about the divisions of time, you have to start really getting specific about what you mean by it. Do you mean, can I determine the interval between two events to an arbitrary precision? (Which gets you into an even more specific question: how do you determine the interval between the two events? With other intervals... and so on.) It's a tricky thing to think about carefully, which was one of Einstein's big observations (there is not a "universal clock" out there in the world that is independent of our frame of reference). --Mr.98 (talk) 15:20, 8 August 2011 (UTC)

I'm not so sure... even though various elements with red or blue shifted spectral lines have the same separation from each other as I recall. --DeeperQA (talk) 16:00, 8 August 2011 (UTC)

How hot is my oven?

The directions for cooking a pizza are "bake at 400F for 22 minutes". I set the oven's thermostat at 350F and after 13 minutes the pizza is slightly burned. How hot is the oven? --Carnildo (talk) 01:41, 8 August 2011 (UTC)

Too hot. 64.134.153.212 (talk) 01:47, 8 August 2011 (UTC)

Indeed, you may want to invest in a cheap oven thermometer to test it out. Also, ovens don't heat uniformly, so you may have hot spots and cold spots. You can probably get an oven thermometer (a cheapo dial kind) at the grocery store for like $5.00. My guess is, though, that your thermostat is broken, and the oven isn't cycling off. --Jayron32 01:59, 8 August 2011 (UTC)

Agreed. I suggest a test. Put it on the lowest temperature setting for 10 minutes (set a timer !) and see if it still gets very hot. If so, the thermostat must be broken. If this is the problem, you shouldn't use it like this, since it could start a fire by going beyond the temperature it's designed for. And, of course, it will destroy pretty much anything you cook in it. (Note that if the oven doesn't get very hot, it doesn't necessarily mean the thermostat is OK. It might always say it's 300 degrees, for example.)StuRat (talk) 02:50, 8 August 2011 (UTC)

It depends on how funky is your chicken. --Trovatore (talk) 02:02, 8 August 2011 (UTC)

... or possibly on how green is your valley. --Trovatore (talk) 02:03, 8 August 2011 (UTC)

I suspect that you are doing something wrong, such as thawing a frozen pizza before cooking it. Looie496 (talk) 02:10, 8 August 2011 (UTC)

...or cooking it in a toaster oven. Looie496 (talk) 02:11, 8 August 2011 (UTC)

I do that all the time. It works great so long as you set the thermostat correctly. (I like to imagine that I'm using less energy this way, but I'm not sure. )APL (talk) 02:49, 8 August 2011 (UTC)

Some gas ovens generate move radiant heat (i.e. infrared radiation) when starting up than when operating at their target temperature. Essentially this is because they turn the burner up high when warming up and lower it when maintaining constant temperature. Most of the time this makes little practical difference but for some sensitive foods, such as breads and cakes, this can cause additional searing (e.g. surface burning) if you put the food in the oven without preheating. So, if you didn't preheat before putting the pizza in, you might try doing that next time and see if it makes any difference. Dragons flight (talk) 08:07, 8 August 2011 (UTC)

I do mine for about three minutes in a microwave. No burning. 92.28.240.88 (talk) 10:33, 8 August 2011 (UTC)

Don't have to worry about burning maybe, but you end up with a pizza flavored slab of rubber. Googlemeister (talk) 19:31, 8 August 2011 (UTC)

That happens when you microwave it for too long. Try halving the time. 92.24.191.250 (talk) 20:59, 8 August 2011 (UTC)

Acetone

Is Acetone a type of VOC?

Yes. See volatile organic compound for more details. Dragons flight (talk) 06:45, 8 August 2011 (UTC)

Self combusting essential oils?

Can anybody explain from a scientific viewpoint how this phenomenon might occur. On the face of it I cannot see how these oils can just ignite at room temperature. Does the washing have any effect on the oils that might alter their nature and make them unstable in some way. Richard Avery (talk) 07:02, 8 August 2011 (UTC)

The article Spontaneous combustion specifically cites Linseed oil as having a high potential for spontaneous combustion. As to why something may spontaneously combust, the process is complex; concepts like Flash point, Fire point, and Autoignition temperature all come into play. --Jayron32 12:18, 8 August 2011 (UTC)

The linseed oil article explains that linseed oil has "drying properties", i.e. the unsaturated lipid components such as alpha-linolenic acid (which is also present according to that article in other drying oils such as perilla oil and walnut oil). That article explains how oxygen slips in and cures/cross-links the oils. This oxidation generates heat, and as explained in the spontaneous combustion article, the heat is produced in greater amounts on the exposed surfaces of rags, and builds up more when they are piled up in an open container. So essentially certain oils like linseed oil are already on "fire" in a chemical sense the moment they're exposed to the air - after that, it's just a matter of building up the heat until an open flame is produced. Wnt (talk) 13:29, 8 August 2011 (UTC)

An interesting consequence, which seems to be agreed in various web forums, is that rags oily with motor oil (which isn't supposed to form a varnish on your engine parts) are in fact no great threat. I think..... Wnt (talk) 13:42, 8 August 2011 (UTC)

How to interpret my test results

To clarify off the bat: I am not asking for medical advice. I've already been to my doctor. What I'm looking for is encyclopedic information to help me interpret my test results. My doctor did some blood test that reveals how my blood sugar level has been for the past 6 weeks. (I didn't know it was possible for blood to store information for 6 weeks, but apparently it is.) The result was a 6.6, which was called "too high". So my question is, 6.6 what? And how does my blood know what its sugar levels have been for the past 6 weeks? Pais (talk) 13:38, 8 August 2011 (UTC)

"6.6" will be your blood glucose level in mmol/L (sometimes shortened to mM).Noticing below, I should say maybe, I'm not au fait with long-term tests. But certainly that is a typical size for a blood sugar reading. Grandiose (me, talk, contribs) 13:41, 8 August 2011 (UTC)

I don't know if this is one of your tests, but the HbA1c test looks for glycated hemoglobin - hemoglobin chemically modified by exposure to sugar. The more sugar in the blood over a roughly 6-week interval, the more the hemoglobin has been altered. I notice that this article says there is a 6.5% threshold for diagnosing diabetes (partly) using this test.

Editorializing a moment, I think it is just appalling that lab results are given in such obscure formats, that don't clearly explain and identify the test or even the units involved so that the patient can understand them. The ideology is that they're for a doctor to see, but of course that only applies if you keep one doctor and you are entirely reliant on him for treatment options. Yet diseases like type II diabetes depend on lifestyle and respond well in early stages to nutritional and herbal options, so the patient deserves and needs primary responsibility for his health, and the respect due an adult. Wnt (talk) 13:52, 8 August 2011 (UTC)

The tests are indeed not for the patient to understand. They lack the competence to do so. They are for the doctor to interpret, based on many years of education and experience, and knowlege of the patient's clinical picture. A responsible adult will seek competent medical attention in case of a serious disease like diabetes, and not risk his health by self-treating themself with nutritional or herbal remedies, which are bound to do more damage than good. Anyone who plays around with something like diabetes is being childish and irresponsible. Dominus Vobisdu (talk) 14:32, 8 August 2011 (UTC)

So instead I should blindly trust someone who has a vested financial interest in keeping me sick? Pais (talk) 14:47, 8 August 2011 (UTC)

Exactly. Doctors would love to give you a prescription for high blood pressure, even though most people could improve it with proper diet and exercise. Heck your BP doesn't even need to be all that high before they try pushing pills onto you. Googlemeister (talk) 14:48, 8 August 2011 (UTC)

And yet, telling the patient to change his diet (with few details), and waiting to see what happens on the next test, are the first responses to such conditions. Certainly nutritional responses are appropriate in borderline diabetes - see [16] for example. Herbal medicines as simple as ordinary "cinnamon" (actually cassia, one of the 50 Fundamental Herbs of traditional Chinese medicine, which is sold as cinnamon in the U.S.) have observable benefits. (See PMID 19930003, PMID 19627193, PMID 21298562; see also [17])

I think it is perfectly possible for a patient to understand the HbA1c test, and just about any other lab test. I think Wikipedia helps greatly in this regard, though there are many other useful sites. Wnt (talk) 14:59, 8 August 2011 (UTC)

Patients can do whatever they please with themselves. Doctors need to get off their high horses. Patients have a right to know every bit of information in their files, even if they do not necessarily understand. --Nricardo (talk) 16:00, 8 August 2011 (UTC)

chock2

in every home there is a tube light along with chock. my doubt is what is the back emf at the time when the supply to the chock is off since at the time of switch on the supply for chock we can calculate the back emf with the inductance value,resistance value,voltage and also we know time constant but iam asking AT THE TIME OF SUPPLY IS OFF SINCE AT THE TIME OF SUPPLY IS OFF, COLLAPSING MAGNETIC FIELD IS VERY VERY FAST AND ITS TIME CONSTANT IS VERY VERY LOWER THEN THE TIME CONSTANT AT THE TIME OF SUPPLY IS GIVEN TO THE CHOCK. IAM ASKING BACK EMF AT THE TIME WHEN THE SUPPLY TO THE CHOCK IS OFF DUE TO THE VERY HIGH RATE OF CHANGE OF COLLAPSING MAGNETIC FIELDvsnkumar (talk) 14:04, 8 August 2011 (UTC)

Is this a repeat of the question #CHOCK, above? (For reference, I believe that chock as it is used here is probably a mild mistranslation of choke.) TenOfAllTrades(talk) 14:10, 8 August 2011 (UTC)

Disconnected from the tube, the ballast will produce a back-emf of several thousand volts (depending on leakage), but the strike voltage is typically 600 to 1000v, or lower for shorter tubes, so this high voltage should not normally be generated. Dbfirs 16:49, 8 August 2011 (UTC)

who started the "information processing theory" ?

thanks

According to this reference cited in the article, it looks like George Armitage Miller and his paper "The Magical Number Seven, Plus or Minus Two" is considered the seminal work in the field. That doesn't mean that there weren't earlier psycologists that worked in the area, or that Miller invented the concept out of whole cloth (that never happens in science), but his work is important enough and early enough to be given prominence in the field. --Jayron32 16:13, 8 August 2011 (UTC)

need some recommendations for digital cameras that are good at recording insects (specifically fruit flies)

It so happens that I can make suggestions on how to spend my lab's budget.

We have a ton of cheap 480x640 web cameras (plus some 1024x768) and while they focus quite well (they take beautiful black and white photos of macroscopic surfaces even with a shallow depth of field) and I'm trying to get better image quality than some of the photos I've taken so far:

Fruit flies 1 (1280x1024+crop)

Fruit flies 2 (1024x768)

I'm trying to create an automated tool for fly tracking and fly counting. However, I also need really sharp images with preferably a large sensor and decent depth of field at that magnification. (Shallow enough that that most objects immediately above the bottom are out of focus, but not too shallow that only one part of the fly is in focus at any one time.) We also want cameras for multiple vials, so cameras under $100 each would be good. These photos were taken at differing resolutions from this camera. Are there any cameras that deliver a live feed that can do better at a good budget? I would also love to use my dslr, or some other point and shoots, but I don't know how to have them deliver a constant feed that can be captured by ImageJ, TWAIN, etc. elle _{vécut heureuse} ^{à jamais} (be free) 18:40, 8 August 2011 (UTC)

Treeline and Kangerlassuaq

What is the minimum temperature necessarily for a tree to grow. I thought it was 52 F. Does the average high or daytime average has to be 52 F? Kangerlassuaq's west coast of Greenland daytime summer have average high of over 60 F about 2/3 in July, it's daytime average cannot be under 52 F, if west coast of Greenland's summer is warm enough how come it can't grow trees. Do Kangerlassuaq, Greenland's climate ever qualify as tundra, it should it be subarctic Dfc-it's summer is quite warm. Is Narsasuaq, Greenland's southwest Dfc subarctic or is it tundra. Our article said some land may occasionally top to 86F, which land does it.--69.229.5.134 (talk) 19:53, 8 August 2011 (UTC)

It's not a simple case of some magical temperature below which no tree will grow, and above which trees will flourish. There are complex environmental reasons why an area will be wooded, and temperature is but one of them. The article Tree line may have some more information for you to read in this regard. --Jayron32 20:05, 8 August 2011 (UTC)

((edit conflict) but in agreement with Jayron) It should be noted that it's not merely temperature that inhibits further tree growth. Altitude, kind of soil, wind velocity, even the species of trees, etc. can factor in. A tundra is also not defined by surface temperatures alone but by the presence of permafrost in the ground and the length of the seasons. But yes, southwest Greenland is subarctic. Anyway, as mentioned in the article on Tree line, Greenland simply does not have seed sources. It is after all, an island, and was completely covered with ice before. It's a bit more difficult for new forests to take root there after the retreat of the ice cover. The few (birch) forests that survived the Ice Age are genetically isolated.

There are, however, afforestation experiments in Kangerlassuaq. And they're thriving quite well from the sound of the articles I've come across.

See the following:

• Sarah Lyall (October 28, 2007). "Warming Revives Flora and Fauna in Greenland". The New York Times.
• Kenneth Høegh (October 28, 2007). "Extended article - "Green forests in Greenland"". POST Greenland.

And the academic paper (if you have access to it, I don't though):

• Ødum, S (1979). "Actual and potential tree line in the North Atlantic region, especially in Greenland and the Faroes". Holarctic Ecology. 2: 222–227. doi:10.1111/j.1600-0587.1979.tb01293.x.

Disclaimer: not an expert by any means. Cheers.-- Obsidi♠n Soul 20:33, 8 August 2011 (UTC)

What vehicle make-&-model has had NO accident fatalities in its entire history?

I wonder what vehicle make/model has had no fatalities in any of its accidents in the entire history of it since the first vehicle of that model was produced. It's so that if I get this vehicle, I'll have less to worry about. Thanks, --68.95.72.154 (talk) 20:51, 8 August 2011 (UTC)

I would speculate that, excepting odd models with very limited runs (say, numbering in the few hundreds or less) or truly unique, one off cars, that there are no wide-production commercial automobiles that have zero fatalities. It is literally impossible to design a car that would be impossible to die in, even extremely rare models where no one has coincidentally died in likely has nothing at all to do with the safety features, but rather just has to do with the fact that so few are on the rule, no one has had the chance to die. There are car models which are safer than others, for various reasons, but no car is "deathproof" and expecting one to be is entirely unrealistic. --Jayron32 20:59, 8 August 2011 (UTC)

Lunar rover. Wanna buy it? Only one owner. Course, you do have to pay for shipping. Clarityfiend (talk) 21:41, 8 August 2011 (UTC)

How many MPH is the bumper rated for on our MRAPs and M1A2 Abramses?

Whereas ordinary civilian vehicles typically have 5-MPH bumpers, how many MPH of speed can an MRAP and an M1A2 Abrams withstand a collision before their bumpers start to dent? --68.95.72.154 (talk) 20:51, 8 August 2011 (UTC)

Regarding the M1A2, tanks don't have bumpers, which even a cursory glance at a picture would confirm to you. Regarding the MRAP, that information would have required someone to have actually tested the dent resistance of that bumper on that vehicle, and given the use of that vehicle, it seems quite unlikely that anyone would have bothered. Which is not to say that tanks and mine-disposal vehicles aren't tested rigorously for their ability to withstand damage; they certainly are, but standards which apply to civilian road vehicles, like the dent-resistance of bumpers, makes absolutely no sense in the context of tanks and other similar military vehicles. --Jayron32 21:02, 8 August 2011 (UTC)

Satellite dish ears

Inspired by this question, what would a sapient race's hearing be like if they had ears shaped like satellite dishes? Subliminable (talk) 21:27, 8 August 2011 (UTC)

chernobyl nuclear plant

Is the Chernobyl nuclear plant site still radioactive? if it is how long would the radiation still last?