Wikipedia:Reference desk archive/Science/2006 August 30

From Wikipedia, the free encyclopedia
Jump to: navigation, search
< August 29 Science desk archive August 31 >
Humanities Science Mathematics Computing/IT Language Miscellaneous Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions at one of the pages linked to above.

Bouncing babies...?[edit]

Hello All!

I just heard that "dandling" or bouncing a baby upon one's knee can cause great damage, as the child's brain will wiggle about...? This sounds a bit off to me, and I haven't the least idea were I would find out whether or not this is true. Any help would be very much appreciated! Russia Moore 01:52, 30 August 2006 (UTC)

See shaken baby syndrome. --Kainaw (talk) 02:03, 30 August 2006 (UTC)
Obviously a an overly vigorous bounce could casue damage, so just use some common sense and don't go nuts with the baby. It makes a difference here too what age of baby we are talking about. If they aren't old enough to have developed the muscles that support the head, then you should be supporting the head no matter what you do. Older babies are different, but again, the amount of force is the issue. pschemp | talk 02:08, 30 August 2006 (UTC)
Just bounce him/her carefully. it nver dud mu ayn dmagew (apart from the slight spelling problem 8-)--Light current 02:28, 30 August 2006 (UTC)
Thanks so much, I should have thought of shaken baby syndrome (I was just reading about child abuse cases today)! Of course I assumed that most people have the common sense not to vigorously shake an infant, but sadly I suppose this is not the case. Anyhow, my baby brother never seemed to suffer from playing horsey... But now when I next get ahold of a bouncable baby I will be able to rest my mind that I am not dashing parental hopes of Ivy Leagues :P -Russia Moore 02:43, 30 August 2006 (UTC)
I think its the acceleration or shock you have to watch.--Light current 02:46, 30 August 2006 (UTC)

When I read of "shaken baby " syndrome I picture some foolish and/or evil caregiver or parent grabbing the baby by the shoulders and shaking it to and from them because they are angry it is crying, so its head flops back and forth from the chest to the back, causing impacts of the brain against the skull. I do not picture someone bouncing the little one on the knee to a tune. Edison 03:58, 30 August 2006 (UTC)

Yes but read my previious post!--Light current 04:02, 30 August 2006 (UTC)
Russia, out of curiosity, did you hear that from the comment in the A.Word.A.Day mailing list? —Daniel (‽) 11:15, 30 August 2006 (UTC)
I did indeed :) Russia Moore 02:38, 31 August 2006 (UTC)
Yay. —Daniel (‽) 08:37, 31 August 2006 (UTC)

Noise Cancelling Within Commercial Aircraft[edit]

I recall being told that a low fequency sound is transmitted in commercial aircraft to cancel the noise of, for example, crying babies. I don't mean noise cancelling headphones (as referred to in a question above) but a sound that is transmitted throughout the whole passenger area.

Does this exist?Downunda 03:42, 30 August 2006 (UTC)

I think you may be thinking of the masking effect of white noise--Light current 03:58, 30 August 2006 (UTC)
You might go for pink noise as well. I'm not sure I would refer to any of them as being low frequency, though. —Bromskloss 08:23, 30 August 2006 (UTC)

Noise similar to that from air handling equipment is sometimes used in offices to mask audibility of speech. Otherwise, in an open plan office, one might hear conversations 50 feet away or more. Sometimes a new installation of masking noise is made over a weekend or holiday. If it is initially turned up too loud, workers may call the janitor to complain of a toilet running without shutting off. Edison 04:01, 30 August 2006 (UTC)

If thats a swishing noise you describe, its white noise.--Light current 04:04, 30 August 2006 (UTC)
Or pink noise. Ok, mabye white noise is swish and pink noise more like swosh. Listen for yourselves: white pink I think I've hear about pink noise being used for precisely this masking purpose. —Bromskloss 19:44, 30 August 2006 (UTC)

induced gravitational effects[edit]

  • in the presence of a magnetic field, charge tends to orbit
  • if charge is constrained to orbit, magnetic field effects are manifested
  • in the presence of mass, light is deflected (tends to orbit)

Q: is it the case that if light is constrained to orbit, gravitational effects will manifest? [say, coherent light in a fibre-optic coil, geometry such that the content of adjacent loops are in phase] 05:00, 30 August 2006 (UTC)

You may be looking for someting like geon? — [Mac Davis] (talk) (Desk|Help me improve)
It's an interesting theory. Nothing in the current understanding of physics predicts such an effect, but we know that we have been unable to combine general relativity and quantum electrodynamics in a coherent fashion, so why not? --LambiamTalk 05:23, 30 August 2006 (UTC)
If light is constrained to 'orbit' no light can escape because its velocity is less than the escape velocity. This sounds like a black hole--Light current 11:34, 30 August 2006 (UTC)
Perhaps the stellar object is surrounded in a cloud of Bose–Einstein condensate?  freshofftheufoΓΛĿЌ  14:22, 30 August 2006 (UTC)
I agree with Lambiam that it's an interesting theory, but as the old saying goes, "There is nothing new under the sun". In fact, at several talks given by Dr Karl Kruszelnicki, he has shown footage of an experiment he took part in that sounds like practically the same idea - by forcing light to travel in a tight orbit (I forget the details of how), they were hoping to observe some relativistic-style effects. Unfortunately, any effects that may have been present were too small for their apparatus to detect, and if their theory had worked there should have been some damn impressive results. Confusing Manifestation 14:03, 30 August 2006 (UTC)

What does benzoxycamphor mean?[edit]

ATTENTION: The REAL longest word in the English language is triskaidekaphobia, meaning fear of the number 13. =)

At Longest word in English benzoxycamphors is said to be potentially the highest-scoring word in Scrabble. Web searches don't reveal any more than it being a chemical compound. I wonder if someone could explain what sort of chemical it is, and where it might be found and/or used. Thanks. KeithD 06:43, 30 August 2006 (UTC)

I do mean benzoxycamphor, as at [1], simply because benzyloxycamphors wouldn't fit on a Scrabble board. Could benzoxy... be another name for benzyloxy...? KeithD 07:32, 30 August 2006 (UTC)
conceivably, compounds are called all sorts of things under the old system. i'd be surprised if it was a legal word however for the purposes of scrabble. Xcomradex 08:38, 30 August 2006 (UTC)
For what it's worth, pharmaceutical sedatives such as valium, xanax, rivotril, and ativan all fall into the pharmaceutical category of benzodiazepines. I'd suspect that the chemical you're speaking of is somehow related. Loomis 11:17, 3 September 2006 (UTC)
They're not related at all. Camphor is a terpenoid, better known as a moth repellent. "Benzoxycamphor" doesn't really make sense as a chemical name, but it could be a (badly named) derivative of camphor.Pikiwedian 07:21, 5 September 2006 (UTC)

Dense material[edit]

Hi. I'm looking for an element/alloy as dense as possible, as cheap as possible and as malleable as possible (in order of descending importance) and without any other undesirable property, such as toxicity. I read the articles osmium and iridium but, while their density is excellent for my purpose, they are cost-prohibitive and, to make matters worse, osmium oxide is said to be very toxic. Any ideas? Thank you very much.

EDIT: OK. The idea is to have weights in the ankles to increase leg strength while running, but they are normally made of a substance which causes the weights be too bulky and uncomfortable, and at the same time, they weigh too little.

If you tell us what you want to do with it, someone may be able to suggest the best thing. --liquidGhoul 11:09, 30 August 2006 (UTC)
Lead would probably be the normal choice for this, although it is toxic if ingested. Just encase the lead in plastic to solve that issue. StuRat 11:22, 30 August 2006 (UTC)
Depleted uranium? 8-). Otherwise brown lead.--Light current 11:37, 30 August 2006 (UTC)
Maybe a better idea would be to put chewing gum on the soles of your shoes. THat would slow you down! OR.. you could try running thro water-- thats hard! OR long grass etc!--Light current 12:03, 30 August 2006 (UTC)
I second the vote for lead. You could encase it in rubber very easily with that stuff that you can get at hardware stores for dipping the handles of tools into to give them a rubber grip. Dismas|(talk) 13:55, 30 August 2006 (UTC)
Not helping, but I wouldn't be surprised if (or I'm pretty sure that) those ankle weights are usually filled with lead in the first place.  freshofftheufoΓΛĿЌ  14:13, 30 August 2006 (UTC)
You didn't ask for this but I'm giving it to you anyway. Ankle weights are not the best way to gain leg strength; in fact, for the amount of torque they put on your knees, it's really really really not worth it. Just go to the gym. Weight training is a very good compliment to aerobic exercise. Anchoress 15:45, 30 August 2006 (UTC)
Or wading thro water. OR the simplest of them all-- cycling--Light current 16:11, 30 August 2006 (UTC)
Your best bet to accomplish what you are looking for is running up slopes or setting a high incline angle on a treadmill.--JLdesAlpins 16:56, 30 August 2006 (UTC)
Or cycling uphill.--Light current 16:59, 30 August 2006 (UTC)
On a treadmill, perhaps. In any case, I can see you're into cycling. :-) —Bromskloss 19:37, 30 August 2006 (UTC)

For some reason, no one's mentioned this yet (enough (Anchoress)). If the masses are more than 1.5kg per leg, you risk serious ligament damage to the knees. You might think that a leg weighs a good 20kg or so, so what difference is 2kg gonna make? But, a leg's weight is distributed with most of it at the top (thigh), so adding 2kg to the feet is very unbalanced. The problem arises in that the knee is designed to take mainly compressive loads, and the artificial mass you've added is pulling down on the knee joint, not the way it's supposed to. Just a heads up. ≈Eh-Steve 18:06, 30 August 2006 (UTC)

Thank you very much for all your responses.


Can algae utilize amino acids from their culture medium? I mean specifically can they use the amino acid directly to build protein, without first breaking the amino acid down, the way an animal can. (I am specifically interested in the species schizochytrium limacinum)ike9898 14:12, 30 August 2006 (UTC)

Algae are not consumers, and hence have no mechanism for which to absorb the amino acid into their cell. --liquidGhoul 14:21, 30 August 2006 (UTC)
Are you sure? Some artifical algae culture media includes peptone. ike9898 14:28, 30 August 2006 (UTC)
I see the problem here, Schizochytrium limacinum is a protist which either acts as a decomposer, or a parasite to algae. Check out Labyrinthulomycetes, it has Schizochytrium in the list of genera. --liquidGhoul 14:55, 30 August 2006 (UTC)

Body fat and menstruation[edit]

What is the minimum body fat percentage needed for a woman to menstruate? I looked in body fat percentage and menstrual cycle and even amenorrhoea, but couldn't find that particular piece of information. CameoAppearance 15:22, 30 August 2006 (UTC)

This link here references a 1981 JAMA article showing that less than 17% body fat is associated with amenorrhea. It sounds like there is more to the story than just that (ie genetic factors) InvictaHOG 15:51, 30 August 2006 (UTC)
I don't know if there is an absolute cut-off for minimum body fat in order for menstruation to occur. For instance, exercise-induced amenorrhea may have something to do with the loss of diurnal variation in leptin as a woman loses weight, and also with relative caloric deficiency due to inadequate nutritional intake for the amount of energy expended. Rather than body fat percentage, studies often use body mass index. See also this study - Cybergoth 16:01, 30 August 2006 (UTC)
Some quotes gleaned from various sources:
  • "Some become amenorrheia at 18 percent, others at 16 or 14 percent," Lohman [director of the body-composition lab at the University of Arizona College of Medicine Department of Physiology in Tucson] says.
  • Why, given a group of women with similar exercise programs and low percentages of body fat, do some experience menstrual problems and others do not? The answer usually relates to nutrition. Women with amenorrhea may be striving to maintain a weight lower than appropriate for their genetics. When the cost of achieving this desired leanness is inadequate nutrition, menstruation will cease.
  • Amenorrhea is the clinical term for cessation of menstrual periods with possible related loss of ovulation. This is generally seen in women who train very heavily and/or have bodyfat below 12-15%; [...] However, research has demonstrated that amenorrhea is not caused by low bodyfat per se. Rather, it appears to be triggered by a long-term negative energy balance, which can result in a low bodyfat.
  • There seem to be many factors which contribute to menstrual disturbance in female athletes. [...] In the early 70s two scientists suggested that a body fat percentage of 17 percent is required for menstruation to begin and 22 percent is needed for menstruation to be maintained. [...] However, this is not the complete answer. Some ballet dancers and swimmers who develop menstrual irregularities when training become more regular when they are not training, even though their body weight does not change. Some amenorrhoeic runners are of normal weight and other studies have found no difference in height, weight or percentage body fat between amenorrhoeic and menstrually-regular runners. [...] There does seem to be a direct relationship between the training load and the degree of menstrual irregularity, at least in runners. One study found a direct relationship between distance run per week and the incidence of menstrual irregularities, although an exact threshold above which menstrual irregularities start to occur has not been found.
It appears that there is no easy answer. --LambiamTalk 16:01, 30 August 2006 (UTC)

tetrachlorodibenzo-para-dioxin (TCDD) and Thyroid disease[edit]

The EPA and the National Academy of Science do recognize that TCDD has some effect on endocrine receptors in humans. Just how and at what dose seems still to be a mystery. Looking for all the information I can get on this subject.

Looks like you've stumped Wikipedia! Rentwa 16:55, 1 September 2006 (UTC)


What benefits would evolving in the shape and density of a mattress have, and how might one evolve in such a way given survival of the fittest and all that? This is not a homework question.  freshofftheufoΓΛĿЌ  15:41, 30 August 2006 (UTC)

Possible sleep configuration of a nuclear mattress family, cave setting
Is this a The Hitchhiker's Guide to the Galaxy related question? I would assume that it would greatly depend on the environment the creature lives in, and the way that the surrounding organisms have evolved. There are probably countless ways that mattresses could evolve, including artificial selection. -- Consumed Crustacean (talk) 15:52, 30 August 2006 (UTC)
Can you clarify the question? Is this a question about the evolution of mattresses qua shape and density, or about the evolution of some species, such as Homo sapiens, into mattress-shaped lifeforms? --LambiamTalk
I don't see why it would be any more unreasonable to expect homo sapiens to become mattresses. It might even be easier that way, because, as you could probably guess, these mattresses can talk.  freshofftheufoΓΛĿЌ  17:14, 30 August 2006 (UTC)
Im gonna have to sleep on that one!--Light current 16:13, 30 August 2006 (UTC)
  • groan* --Froth 14:36, 31 August 2006 (UTC)
Stackability would ensure efficient sleeping, transport, and sexual arrangements, sound absorbency would mean a quieter environment, crashes and jumping from a great height would rarely be fatal,...--Shantavira 17:44, 30 August 2006 (UTC)
Yes! Stackability, now that would be useful. I can imagine scenarios where a creature would give up their ability to walk instead gaining the ability to bound short distances, most of them being in extremely docile environments where food supply is always guaranteed.  freshofftheufoΓΛĿЌ  05:58, 31 August 2006 (UTC)::

Over active thyroid[edit]

Is it possible to:

  • Be thin as a rake (ie BMI = 18)
  • Not sleep well
  • Have very fine hair (someties falling)
  • Have Very smooth skin
  • Always be 'on the go'
  • Have limited attention span (scatter brained)

and not have an over active thyroid?--Light current 17:21, 30 August 2006 (UTC)

Since you're using an AND logical construction, all of the conditions must evaluate to YES in order for the function to also result in YES. Since it is not possible to be as thin as a rake (even the skinniest humans easily eclipse common rakes), I can therefore safetly conclude that the answer to your question is no.  freshofftheufoΓΛĿЌ  17:34, 30 August 2006 (UTC)
OTOH, from the principle of explosion, anything follows from a contradiction. If a person is thin as a rake, we have a contradiction, because you showed that they're not. So, anything follows. Even thyroids on steroids. —Bromskloss 19:33, 30 August 2006 (UTC)

Depends on thet size of your rake dont it? 8-) OK If you have all the above conditions, can you stil NOT have an over active thyroid?--Light current 18:13, 30 August 2006 (UTC)

Did you try to create that userbox "This user wants to be convinced that (s)he has an over active thyroid", with a nice picture of one ? -- DLL .. T 18:41, 30 August 2006 (UTC)

I know not of what you speak, dear sir!--Light current 18:43, 30 August 2006 (UTC)

Add in the other common symptoms like high appetite, diarrhea, headaches, and high libido and you are closer to describing a textbook case of hyperthyroidism, not that you should ever be using wikipedia to fetch medical advice... To more directly answer your question, see Amphetamine or UBS Guy for a possible alternate explanation --Jmeden2000 20:41, 30 August 2006 (UTC)

Ah well, she aint got diarrea, headaches, and is as cold as a fish! How now? Should I be telling her to go to the doctor TITQ--Light current 20:46, 30 August 2006 (UTC) Oh yeah I forgot to say she has good appetite but somtimes misses meals cos shes so busy running round.--Light current 21:41, 30 August 2006 (UTC)

If you think the factors are abnormal then a visit to the doctor would be in order. Consider that you may be projecting hypochondria, not that I am qualified to make that diagnosis (perhaps i am a vicarious psychoanalyst but again this is no place for medical advice). --Jmeden2000 21:00, 30 August 2006 (UTC)
It is certainly possible to have those symptoms and not have hyperthyroidism. However, those symptoms should certainly prompt thyroid testing, as they are commonly associated with an overactive thyroid. InvictaHOG 21:05, 30 August 2006 (UTC)

What do I say to try to get her to go? Shes quite strong willed and may resent me suggesting she is not completely fit. She says shes always been v thin and her brother is the same. Could he have it too?--Light current 21:13, 30 August 2006 (UTC)

If she doesn't want to listen to you, she won't. Just give it your best try. If she's going to the doctor anyway, it's just a simple blood test. InvictaHOG 01:07, 31 August 2006 (UTC)

THanks to all for the replies!--Light current 01:11, 31 August 2006 (UTC)


Does editing WP make you more intelligent? If so, how long does it take to work/ 8-?--Light current 18:55, 30 August 2006 (UTC)

Yes, of course. Within a month of editing at Wikipedia you will have amassed a lifetime of knowledge about exploding whales, masturbating pigeons and how to suitly emphazi a question. There are plans to release a pill which will contain all this information and transmit it into the brain of the taker, which will render all your gains obsolete soon though. —Daniel (‽) 18:47, 30 August 2006 (UTC)
WP won't be of much help if you can't even remember to sign your posts.  ;-) --hydnjo talk 18:50, 30 August 2006 (UTC)

Sorry--Light current 18:55, 30 August 2006 (UTC)

See, you're getting smarter already. 9-) --hydnjo talk 19:17, 30 August 2006 (UTC)

Why is your writing so small?--Light current 19:23, 30 August 2006 (UTC)

Because I'm writing quietly. --hydnjo talk 19:34, 30 August 2006 (UTC)

Why are you writing quitely?--Light current 19:36, 30 August 2006 (UTC)

So as to not call much attention to some of my posts, but It doesn't always work. --hydnjo talk 19:43, 30 August 2006 (UTC)
Umm, more like a device to give the impression of a footnote or a parenthetical. --hydnjo talk 20:02, 30 August 2006 (UTC)

Er.. yes?--Light current 20:30, 30 August 2006 (UTC) yes, excactly. --hydnjo talk 21:14, 30 August 2006 (UTC)

Not to be a pain, but...please don't use the reference desk as a chat room. How about using your talk page? ike9898 21:23, 30 August 2006 (UTC)

Im not using it as a chat room. We may be digressing somewhat-- thats all.--Light current 21:26, 30 August 2006 (UTC)
And I certainly have no intention of sharing a room with Lc. --hydnjo talk 21:58, 30 August 2006 (UTC)

In all seriousness... using your brain in any intellectual pursuit, from doing logic puzzles to writing research papers, improves your thinking ability. Editing Wikipedia surely qualifies as the latter ... or at least it should, if you're doing it right. --Ginkgo100 talk · e@ 20:33, 30 August 2006 (UTC)
  • Intelligence and knowledge are two different things, but yes doing stuff that challenges your brain like reading and editing Wikipedia is probably going to be benefitial for your IQ. - 07:50, 31 August 2006 (UTC)
My typing and grammar have gotten much better since I started Wikipedia (especially my typing, I couldn't touch type before and now I am quite proficient!). --liquidGhoul 12:32, 31 August 2006 (UTC)

creatine article[edit]

in the creatine article there is a statement that there are vegetarian sources of creatine. I have not been able to find out what those sources are so i would much appreciate further information on the subject. 19:28, 30 August 2006 (UTC)Smith

Vegetarian creatine can be obtained via chemical synthesis using plant-derived amino acids.--Light current 19:35, 30 August 2006 (UTC)

Asking a subject reference question[edit]

Aha! I think this is the feature I was looking for. Thank you!

...Do you have a question? --Ginkgo100 talk · e@ 20:31, 30 August 2006 (UTC)
He/she was just seeing if they knew how to ask a question if they needed too. He/she thanked as for the future service we may do to him. We are, after all, "in the service." — [Mac Davis] (talk) (Desk|Help me improve)
You're welcome (to what I'm not sure, though). DirkvdM 08:44, 31 August 2006 (UTC)

Iran and Nuclear Power[edit]

Why does Iran want to build nuclear power plants when they have such a large oil reserv? 20:03, 30 August 2006 (UTC)

I wonder!--Light current 20:32, 30 August 2006 (UTC)
For lots of information see Iranian nuclear program; their rationale is treated at Iranian nuclear program#The Iranian Point of View. Melchoir 21:10, 30 August 2006 (UTC)
They're afraid of global warming, which, disputably, will cause a drastic rise in the seagull bagel population. In the 147th passage of the Qu'ran, it states "Jihad shall be against the non-Islamic, and bagels." It is really a three-fold problem for them. The educated Islamofascist know that global warming will simultaneously cause a spike in bagel populations, Kill All Humans, and, because humans are much more productive when temperatures are hotter, the fucking infadels will have better technology. — [Mac Davis] (talk) (Desk|Help me improve)
why does the US want to build nuclear power plants, when they have such large oil reserves (not to mention bagels). Xcomradex 21:58, 30 August 2006 (UTC)
Both parts of your statement are completely wrong; the US does not have enough current oil production to meet it's own needs, an it's not currently building nuclear power plants (although perhaps it should be). StuRat 03:21, 31 August 2006 (UTC)
So they have more enriched uranium and plutonium than Iran (and prob everyone else put together) of course. 8-)--Light current 22:02, 30 August 2006 (UTC)

It's just a cover story so Iran can build nuclear weapons, even the normally gullible Europeans can see this. StuRat 22:05, 30 August 2006 (UTC)

Really? I would never have guessed that! 8-)--Light current 22:06, 30 August 2006 (UTC)
Probably, yes. But this is the science reference desk, and that is not a falsifiable hypothesis. Melchoir 22:18, 30 August 2006 (UTC)

There's a lot of people who think like StuRat (and on this rare occasion I do happen to at least partially agree with him) but the Iranians argue that a) they want to make sure their petroleum reserves last as long as possible, and b) those petroleum reserves are more valuable being sold than generating power domestically. See nuclear program of Iran. --Robert Merkel 22:25, 30 August 2006 (UTC)

After Pakistan said they weren't working on nuclear weapons, then completed one, then North Korea did the same, anyone who believes that Iran, a country which publicly calls for the destruction of Israel and publicly supports a terrorist organization trying to do just that (Hezbollah), just wants "peaceful" nuclear energy, is truly naive. StuRat 23:10, 30 August 2006 (UTC)
Also, try Iran's civilian nuclear program. Melchoir 22:35, 30 August 2006 (UTC)
I think that Iran's leaders are playing two games at once. One is the development of what is currently a nuclear program of dual-use technology—everything in their program ostesibly has a peaceful purpose, though all of it could also be diverted for a weapons program as well. This gives them a little room to claim that they are having their rights trampled on—according to the NPT, peaceful nuclear programs are allowed, though with some qualifications. The second game is related to the first; they get to be a leading voice in the region confronting the United States, claiming scientific progress, and using the entire incident as an opportunity to point out the double standard that the U.S. has towards Israel's nuclear weapons program. The Iranians also are fond of saying something very strong—i.e. that Israel should be wiped off the map—and then backing down from it with a more mild explanation—i.e. that they were only talking about it in defensive terms, and that they were just warning Israel not to attack them unprovoked. It puts them in an advantageous regional position, and I don't think its a coincidence that their hardliner president dresses in Western clothes and looks more like a Western politician than he does a Shiite cleric.
As for the oil reserves—I'm pretty sure even the most optimistic estimates point to a falling off of Middle Eastern oil reserves within the next two decades or so, which will put Iran and everyone else over there up a creek if they don't have fallback industries and energy production.
Are they making a bomb? Probably not at the moment, not as a full program anyway. They're hedging their bets for one though, trying to get just enough technology that they'll be able to work one up over time (the same way Pakistan did theirs, which took decades to make because they were content with doing it slowly). At the moment they are pursuing so many alternative routes—uranium, plutonium, etc.—that they could drop one of them from international pressure and still be able to pick up the slack in another area.
Most analysts don't think Iran could develop a bomb within the next decade, though. The real regional danger of Iran getting a bomb is less that they would use it against Israel, but would rather use it as a check against Israel using their own bomb against them, and then hope to beat Israel at conventional warfare, IMO. (My personal biggest fear at the moment is that Israel will, one way or another, get involved in a war with Iran as they are currently with Lebanon, and then drag the United States/United Nations in with it.) --Fastfission 23:37, 30 August 2006 (UTC)
It's true, Iran has an enormous army with an enormous number of personnel and likely a pretty hefty cache of land artillery. Yet its air force and navy are practically non-existant. With the possible exception of some long-range conventional missiles, how could Iran possibly conduct any sort of conventional warfare against Israel? How would they even get there? Would several hundred thousand Iranian troops be zipping through a couple of thousand miles of desert, through US occuppied Iraq and then Jordan on dune buggies? Loomis 01:26, 1 September 2006 (UTC)
Any claim Iran makes to only want a peaceful nuclear program was shown to be false by their rejection of Russia's offer to provide nuclear fuel and get the spent fuel back. This would provide Iran with all the nuclear power they wanted, but deny them the possibility of enriching the fuel further for use in nuclear weapons. Therefore, Iran rejected the offer. StuRat 23:45, 30 August 2006 (UTC)
Yes, because Iran's experience with OPEC has taught it that building an energy infrastructure around a foreign source of fuel is such a good idea. Melchoir 23:57, 30 August 2006 (UTC)
I don't think a single rejection of a plan can be used as a convincing case, especially when it is a plan that forces them to basically be at the diplomatic mercy of another country. (And it is not like Russia has not used denial of resources before as a way to throw around weight, i.e. by denying oil to Ukraine and things like that.) If I were a president of a country like Iran, I wouldn't be too eager to have my nuclear program be completely at the mercy of the Russians. I think it is more convincing that Iran has continually sought dual-use technology even when there have been options otherwise, and that they have so far been resistant on safeguards. --Fastfission 00:32, 31 August 2006 (UTC)
Unlike OPEC's oil, even if Russia stopped supplying nuclear fuel, it would be years before Iran's current nuclear fuel supply would be spent, giving them plenty of time to switch to another supplier or back to oil. Therefore, any Russian threats to cut their supply would be highly ineffective. StuRat 03:18, 31 August 2006 (UTC)

the US's opinion back during the days of the Shah was iran would need five nuclear power plants by 1994 (number from memory), and they even helped arrange a consortium with germany and france to build said powerplants. yet fast forward a few years and look what happens. Xcomradex 02:07, 31 August 2006 (UTC)

Ahh, but the Shah was America's friend! (Not the peoples friend)--Light current 03:13, 31 August 2006 (UTC)
One should never put all of one's eggs in one basket. As was indicated before one can ask a similar question of many other countries (and also why they would need or have more right to nuclear weapons, for that matter). The Netherlands has the biggest gas bubble in the world. So what do we need nuclear plants for? A better question might be why they don't focus on solar energy, considering their climatic situation. Or do they? I don't know. DirkvdM 08:58, 31 August 2006 (UTC)

To offer a Canadian perspective, just as Iran's oil reserves may some day run out, necessitating the need for nuclear power, up here we fear that global warming will eventually eliminate all the snow from falling, thus destroying an extremely important aspect of our tourism industry, alpine skiing. Yes it's true, we fear that one day Canada will face a shortage of snow. With that in mind we're currently working on a snow making machine, using technology which, completely coincidentally, can be used to create a weapon that can destroy the evil American regime which should be wiped off the face of the map. Not to worry though, global warming is real, and we truly believe that such a machine will be necessary once all of Canada's snow has melted away and no more will continue to fall. Oh, and by the way, death to America. Peace y'all! Loomis 09:03, 31 August 2006 (UTC)

That's why nobody ever asks for a Canadian's perspective.  freshofftheufoΓΛĿЌ  12:14, 31 August 2006 (UTC)
Ouch! Why's that? Because nobody can handle the truth? Loomis 00:38, 1 September 2006 (UTC)

I agree that the question should be "with all the possible forms of energy available to Iran, why do they insist on the one form that also allows them to develop nuclear weapons, and reject any method that would allow them to develop peaceful nuclear power, but prevent them from developing nuclear weapons ?" Hmmm ... I just can't figure it out. StuRat 13:03, 31 August 2006 (UTC)

I'm just as confused as you are Stu. What do you suggest should be done? I say we force Iran to allow UN observers complete access to every nuclear power plant in Iran. That way, we'll all be safe in the knowledge that Iran won't be building nuclear weapons under all of our noses. That way, we'll be safe in the knowledge that Iran will only be building nuclear weapons openly and honestly under strict UN supervision. Loomis 01:06, 1 September 2006 (UTC)
The only possible solution I see is a military action, most likely taken by Israel, with US covert support. The UN will first put some weak, thoroughly useless sanctions on Iran, and will violate even those. This will have absolutely no effect on Iran. Then, when it is clear that Iran has nearly completed it's nuclear weapons, the only option left will be military action. I suspect the sites will be bombed with "bunker-buster" bombs (possibly low yield, tunneling nukes). It's too bad we don't have an effective UN that could actually take the actions necessary to get Iran to stop peacefully. That would take total sanctions on Iran, sealing all of the borders. The weakness of the UN makes war inevitable. StuRat 10:47, 1 September 2006 (UTC)
If all countries with nuclear plants would allow that (do any now?) and Iran would still not agree to it, then they would look pretty suspicious. It's mind boggling how often people find it perfectly normal to do unto others what they would never allow those others to do unto themselves. DirkvdM 09:04, 1 September 2006 (UTC)
Under your theory, since police have guns, we must provide all criminals with guns, as well, so we treat everybody equally. I would expect the US would agree to UN inspectors of their nuclear reactors, if that would get Iran to do so. However, inspecting US nuclear plants would be a complete waste of time, as the US already has more nuclear weapons than it knows what to do with. StuRat 10:33, 1 September 2006 (UTC)
I skipped that last bit to avoid complicating matters too much, but thank you fro bringing it up. You ma now attempt an answer to that hypocricy as well. :)
The police (and the army if needs be, but that never comes up domestically) should have a "monopoly on violence" as we say in Dutch. Translate this to international affairs. Who is to be the police? One specific country or a group of coutries or a joint effort of all countries in the world? Suppose the separate states in the US were different countries (not too far from the truth). What if California, in alliance with the rest of the West Coast would claim a right to all nuclear facilities and weapons and would invade other states if they had any plans of developing their own technology (or economic system, or whatever)? DirkvdM 13:04, 1 September 2006 (UTC)
OK, I can answer your silly scenario. Let's now say that Pennsylvania is dedicated to the total destruction of Virginia, says so publicly, and supports various terrorist organizations that launch missiles into Virginia, send suicide bombers into Virginia, and stockpile weapons in West Virginia, on the border with Virginia. Let's also say their terrorist organization is destabilizing West Virginia and causing destruction to it's infrastructure by Virginians trying to defend themselves from these constant attacks. Now Pennsylvania is claiming they need nuclear power, despite huge oil and gas reserves. They have rejected any attempt to monitor their nuclear plants to be sure they aren't building nuclear weapons and have been caught numerous times cheating on the nuclear nonproliferation treaty. Now, under these circumstances, absolutely, those states with nuclear weapons should all work together to prevent Pennsylvania from ever getting them. Hopefully, responsible states without nuclear weapons will also join in. If nothing else works, Pennsylvania should then be attacked, before it gets nuclear weapons. StuRat 06:12, 2 September 2006 (UTC)
But the US already have nuclear weapons, so are you saying we're too late with the invasion? Or weren't you talking about the US? DirkvdM 09:03, 2 September 2006 (UTC)
The word is "has". If there were aliens who could keep everyone from getting nuclear weapons, including the US, then that would be a good thing. However, as none seem willing to help us out that way, the next best thing is for as few countries as possible to have them; ideally only the "good" countries (which won't just use them to kill off or enslave everyone else in the world, as the Nazis, imperial Japanese, or Soviets would have, had each been the only country with nukes). StuRat 01:23, 3 September 2006 (UTC)

I don't see why the whole thing has to be turned pro or anti-US. Putting aside the US for now, there are still quite a few countries around the world that are stable and (relatively!) sane enough that no one worries whether or not they possess nuclear capabilities. Check out the list of countries with nuclear weapons. The Brits have the bomb, and that doesn't concern me one bit. The French...well despite being French and all, I'm not at all worried about their nukes either. As for Russia and China, though they may be misfit states, they still seem to be sane and practical enough to me (and have the track record to prove it) that they have no intention of launching an unprovoked nuclear strike on anyone. As for India and Pakistan, their main beef is with each other. Both being secular, the old Mutual Assured Destruction (MAD) principle would seem to take nuclear war out of the picture. And of course there's the Israelis, love'em or hate'em, whatever nukes they may have might just as well be harmless drones, built entirely for deterrent effect. I just can't see Israel ever using them, ever, even as a second strike. It just doesn't jive with the Israeli psyche.

The article also points out that countries like Canada, the Netherelands, Australia etc...(I picked those totally at random :) have all the technology necessary to build a bomb in a matter of weeks, but that doesn't concern me either. These countries are, (at least for the most part!) sane and pacifist, and see no use in possessing nuclear weapons, and rightly so, nobody seems at all concerned with whatever technological capabilities they possess.

But then you come across countries like Iran and North Korea. I'll leave North Korea aside for now. In the case of Iran though, the old MAD principle actually doesn't seem to apply. Even the Soviets weren't insane enough to launch a first strike, because to do so would risk an equally devastating reply from the US. Iran, on the other hand, is a different story. With its shahidist mentality, MAD would actually seem to have no application. "Nuke the Zionists and who cares if they nuke us back? We'll all go to heaven and they'll all go to hell". Now THAT scares the shit out of me. People speak of "double standards"...well I'd say there's a pretty solid logical basis for these "double standards". Loomis 14:29, 1 September 2006 (UTC)

Well said. Just as sane, responsible gun owners are OK, but giving guns to insane criminals is very bad, so would giving nukes to Iran be a very bad thing. For example, I would not be opposed to Japan getting nuclear weapons, as I only see them being used to prevent an attack by North Korea. StuRat 05:59, 2 September 2006 (UTC)

Most distant spacecraft visible from Earth[edit]

I have two questions:

1. What is the most distant spacecraft visible to telescopes on Earth? 2. What is the brightest spacecraft not in orbit around the Earth, and how bright is it?

--Bowlhover 21:41, 30 August 2006 (UTC)

The brightest not-in-orbit spacecraft would probably be something very close, maybe New Horizons, launched in January and by my calculations about 7 million miles away. The Wilkinson Microwave Anisotropy Probe is technically not in orbit around the Earth (it orbits the Sun-Earth L2 point about 1.2 million miles away). I'm not certain if it ever comes out of the earth's umbra, but if it does, it's probably pretty dang bright. (Relatively speaking) -- Plutortalkcontribs 22:27, 30 August 2006 (UTC)
I thought about mentioning WMAP, and am likewise unsure of the umbra. On the other hand, SOHO is at the L1 point, and so is certainly in plenty of sunlight, but is also completely obscured by solar glare. If you don't like those, the current leader is likely SMART-1 orbiting the Moon, though it's about to crash. — Lomn | Talk 22:39, 30 August 2006 (UTC)
Well, Earth has an angular diameter of 0.24 degrees to the WMAP. The Sun has a diameter of 0.53 degrees, so our planet can't block more than 21% of the Sun's light. In other words, the WMAP is in sunlight. Anyone know how bright it is? --Bowlhover 05:21, 31 August 2006 (UTC)

Why can't we feel the mantle heat through the crust of the earth?[edit]

I have done a lot of research into plate tectonics and the geology of the earth on Wikipedia. I have learned a LOT, but I can't seem to find an answer to the following (basic) question anywhere:

If the mantle inside the earth is molten rock at 1200 to 2200 degrees (F), why doesn't any of that heat pass through the earth's crust (by convection) and reach the surface?

If there is THAT MUCH heat energy inside the earth, I would think that we should be able to experience at least SOME of it on the surface.

Thanks in advance!  :-)

Tim Barber (Harrisburg, PA)

We do! Ever heard of hot springs, volcanoes etc. THe miles and miles of rock forming the earths crust are a good insulator thankfully--Light current 22:09, 30 August 2006 (UTC)
Yes, rock is a good insulator, so any heat that the mantle delivers to the crust will be radiated away into space. It's like putting a block of wood on a stove--the wood (except for the part that touches the stove) won't feel hot. --Bowlhover 22:15, 30 August 2006 (UTC)
Also, the temp a few hundred feet underground is largely heat rising from the mantle. Only near the surface does heat from the Sun become dominant. StuRat 22:30, 30 August 2006 (UTC)
Yes for instance in some caves I recently visited, the temp is constant 12 deg celsius--Light current 22:34, 30 August 2006 (UTC)

We do feel it! If it weren't for the heat coming out through the crust from the interior of the Earth, the Earth surface where we live would be very much colder than it is. The heat is produced (mostly) by radioactive decay (and, by the way, goes through the crust by conduction, not convection). --mglg(talk) 22:58, 31 August 2006 (UTC)

Correct, the heat gets to the crust by convection, then goes thru the crust by conduction (excluding geysers and lava spewing out of volcanoes). StuRat 10:28, 1 September 2006 (UTC)

I need to find critics to the socialist ideas.[edit]


Criticisms of socialism you say?--Light current 22:32, 30 August 2006 (UTC)
Do you mean finding the people themselves? —AySz88\^-^ 00:24, 31 August 2006 (UTC)
Not that you have any preconceptions of course. :) Ah, I get it, socialism makes so much sense that you can only think of pros and need others to make up the cons for you. :) DirkvdM 09:07, 1 September 2006 (UTC)

Question on the derivative market[edit]

Question on the derivative market and particularly on the process with several volatilities:

I would like to know if any process with more than one volatility for an underlying asset exist.


Economics homework? Its so easy with WP--Light current 00:27, 31 August 2006 (UTC)

Please do not double post. --LambiamTalk 02:44, 31 August 2006 (UTC)

Perpetual Motion[edit]

Is there anyone i can contact who is an expert in perpetual motion?

Nick Muller

Perpetual motion is a good read with some interesting external links. --hydnjo talk 23:57, 30 August 2006 (UTC)
If you want to take them at their word, the guys as Steorn would have you believe they are the best in the business. Rockpocket 05:19, 31 August 2006 (UTC)
But, if you read the long discussion below, they are mostly likely wrong. — QuantumEleven 07:41, 1 September 2006 (UTC)
Some call me an expert in my field, unfortunately though I stop every night to sleep. So I suppose I wouldn't qualify as an expert in perpetual motion. Loomis 04:29, 2 September 2006 (UTC)