Wikipedia:Reference desk/Archives/Science/2007 April 25

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1 April 25

[edit] April 25

[edit] Comets

What comets have recently been discovered, and, when will a comet be visible from earth next? --72.78.191.196 00:31, 25 April 2007 (UTC)Meepy123

Comet#Currently visible comets will help with the second part of your question and Comet McNaught was discovered just last year. Rockpocket 00:33, 25 April 2007 (UTC)

[edit] Lightning Safety

Hello. When you are golfing and lightning strikes, would it be a good idea to hide in your golf cart? I already know you shouldn't hide in an ATV because the rubber tires won't protect you. Thanks. --Mayfare 01:09, 25 April 2007 (UTC)

No. According to the Golf Course Superintendents Association of America [1] one should:

Not stand under a lone tree. This is where most people are injured or killed.
Stay away from water.
Stay away from your golf clubs.
If your shoes have metal spikes, take them off.
Move away from your golf cart.
If stranded in the open, go to a low place such as a ravine or valley.

Rockpocket 01:19, 25 April 2007 (UTC)

Also, if you think you are about to immediately get struck (I think there are sometimes warning signs; hair standing on end, hearing crackling noises, lots of strikes around you), there is a lightning safety position, which is a crouching position with your feet together and elbows on your knees, hands on your ears or head (I have seen a few different variations. Google it ). This not only reduces your height, but provides a safer path for the lightning (through your legs rather than your torso), as well as reducing damage from lightning traveling along the ground. --Bennybp 02:55, 25 April 2007 (UTC)

And furthermore, it's my understanding that the protection vehicles provide isn't due to the rubber tires, it's due to the electricity travelling through the frame to ground. I'll look and see if I can find a citation for that. Edited to add (after ec): A cursory look at lightning rubber tires turns up numerous results supporting that premise. Anchoress 03:20, 25 April 2007 (UTC)

The car is forming a Faraday cage and the current will travel through the chassis instead. It's been tested on Top Gear. --antilived^{T | C | G} 03:19, 25 April 2007 (UTC)

So just a little perspective: lightning just traveled through three miles of air (a very good insulator as you'll note only a few feet insulates the highest voltage transmission lines). A quarter inch of rubber isn't going to stop it. Also, I believe it is points or tips (i.e. the end of golf clubs, tops of trees, your head) that causes the mist favorable field lines to form for a lightening strike. This is why lightning rods are so pointy. This is also why sticking a pointy golf club in the air isn't safe even if it's not the tallest object. After a lightning strike, a car can still be a dangerous object as some charge may remain in the chassis. --Tbeatty 05:27, 25 April 2007 (UTC)

It's not about the rubber tires stopping the lightning, but whether it would encounter less resistance by another path. If someone is standing next to the cart, for example, the lightning may jump to them and reach ground that way. StuRat 07:20, 25 April 2007 (UTC)

Exactly. During lightening, it is indeed a good idea to seek cover in a car, as its metal chassis makes the lightening bolt travel around you, and you stay unhurt in this Faraday cage. This works, however, only, if the metal chassis is enclosing you, i.e. if the car has a metal roof! Stay away from open vehicles (withou roof or with cloth roof) such as convertibles, quads, carts or the like. Simon A. 11:30, 25 April 2007 (UTC)

Lightning rods used on commercial buildings and utility unstallations are less pointy now than they were in the old days of lightning rod salesmen putting them on barns. And I'vew read of at least one person being killed by a lightning strike while inside a metal hard-top car. The Faraday Cage effect seems not to be perfect. But I would feel far safer in a hardtop car than in a golf cart, or on the ground outside. Lying on the ground might not be a good itea because of the voltage gradient in the ground causing a difference of hundreds of volts between points a few feet apart. If reduced to squatting, perhaps you could squat on one foot (not to say tuck your head between your legs and kiss you a$$ goodbye). Edison 16:22, 25 April 2007 (UTC)

Some rare bolts of lightning are so powerful they might just vaporize the car, offering little protection to the occupants. StuRat 20:08, 25 April 2007 (UTC)

[edit] IVF page

Who worte the information on the In Vitro Fertilisation page? I need to do a refernece for a school assignment, so I would like the answer ASAP. Ta

– — … ° ≈ ≠ ≤ ≥ ± − × ÷ ← → · §

—The preceding unsigned comment was added by 121.45.61.230 (talk) 04:16, 25 April 2007 (UTC).

Wikipedia's articles are written collaboratively by any number of editors, both registered and anonymous. If you need to cite the page, there is a Cite This Page link on the sidebar. If you are interested in the editing history, there is a history link on top. Splintercellguy 04:28, 25 April 2007 (UTC)

(edit conflict)

Like most of our articles, it was written by many people. You can view the article's history page if you're curious. But you don't need to cite those contributors by name when referencing the article -- see here for information on how to cite Wikipedia articles, or just follow the "Cite this article" link in the left toolbar of the article you wish to reference. —Steve Summit (talk) 04:36, 25 April 2007 (UTC)

[P.S. Looks like you had fun with the "Insert" menu at the bottom of the Edit box, for all those special characters! But the one you wanted was "Sign your username: ~~~~", which would have signed your post.]

Take a look at the Welcome page for an introduction. For information on how to cite (or reference) Wikipedia articles - and why you probably don't want to - use the "Cite this article" link on the far right of the page; or click here. --h2g2bob 07:58, 25 April 2007 (UTC)

[edit] Model of the tongue

cross section of entire tongue. [Mαc Δαvιs] ❖ 18:49, 25 April 2007 (UTC)

Any ideas on how to make a model of the tongue ? —The preceding unsigned comment was added by 196.23.241.158 (talk) 08:47, 25 April 2007 (UTC).

No. But it prompts funny ideas like filling your mouth with plaster, holding your tongue very still until the mold hardens, then find some way to get the tongue out of the mold and the mold out of the mouth, and then cast a positive. But if you actually try this out and then have a big lump of gypsum stuck in your mouth, it's not my fault. SCNR. Simon A. 11:36, 25 April 2007 (UTC)

You can buy beef, pork, or lamb's tongues at your local odd-foods shop (deli, Chinese supermarket, better general grocery stores, etc.); it might be better to take a casting from one of these. Lamb tongue is even in the right scale.

Atlant 12:26, 25 April 2007 (UTC)

If you want to add some taste buds (chances are that these may not cast very well), you could cover the tongue in the sort of studded rubber used on the underside of doormats etc. You may also want to freeze the tongue before casting the mould from it: this would prevent the tongue from moving while casting, and as it would shrink in size as it thawed (as the tongue is mostly water), you could then remove it from the mould more easily. Laïka 13:16, 25 April 2007 (UTC)

If you're friendly with your dentist, just ask him/her to fill your mouth with alginate (much safer than plaster!), and then pour something into the mold. There are recipes for Gummi Bears on the Internets that might make a fun squishy tongue that you could snack on after the science fair. --TotoBaggins 14:20, 25 April 2007 (UTC)

I thought he meant the entire tongue, not just the front. As you can see, you definitely, under any circumstances, do not want to put any plaster or alginate, or anything to make a mold of your own tongue. Also, It would probably be extremely difficult to keep your tongue absolutely still over the drying period. You would have to inject it with a muscle relaxant for best effect. [Mαc Δαvιs] ❖ 18:48, 25 April 2007 (UTC)

The Kelly Lochbaum Vocal Tract model is the industry standard for speech-processing and computer voice synthesis. Nimur 04:48, 27 April 2007 (UTC)

[edit] Name for biological phenomenon.

Hey guys. I used to now what this was called but it's gone from my head.

It's the name for the phenomenon exhibited in certain animals. They enter a trance-like state when tipped upside down. I believe both sharks and rabbits exhibit this quality.

Any ideas? 213.48.15.234 09:08, 25 April 2007 (UTC)

Tonic immobility. Wikipedia Google Queen 09:59, 25 April 2007 (UTC)

That's the one! Thank you crazy lady! 213.48.15.234 10:39, 25 April 2007 (UTC)

Isn't it Tharn,. or was that just a made up word.

Yes, Tharn was made up for the book Watership Down. Shui9 20:58, 25 April 2007 (UTC)

[edit] Virtual Stellar Map

Can anyone suggest where I could find a 3D map of our stellar neighburhood? What would be really nice is some kind of animation that illustrates the location of the 100 closest stars and into which one could virtually "navigate". Thanks.--JLdesAlpins 10:25, 25 April 2007 (UTC)

Play Elite (computer game). There, you fly through a 3D map of our stellar neighborhood. Or simply google for "3d map of close stars", and you get lots of hits. Simon A. 11:40, 25 April 2007 (UTC)

The computer programme Celestia is very good, although after a couple of hours flying around different stars, you begin to notice that most stars look the same. Laïka 12:19, 25 April 2007 (UTC)

[edit] Glycemic Index and carrots

Hi, Being partially bilingual, I noticed the Glycemic Index page in Spanish gives out-dated information (according to the English page) on carrots and their GI value.

I have put a note on the discussion page of the English version, and another (in Spanish - it took me a long time!)on the Spanish discussion page (which was empty).

I cannot (as a new user, being non-medical, and not having very good Spanish) bring myself to edit the pages in question.

Have I done the right thing? Will it get fixed?

The Spanish version wouldn't let me log in with my user name etc. Is this normal? Does it matter?

Thanks to anyone who takes the time to reply...

MarcTurner 11:02, 25 April 2007 (UTC)

You couldn't log in because English WP users are separate from Spanish WP users (and German, and Dutch, and so forth). Just register there under the same name. Past that, be bold and fix what you can on the page in question. Plenty of people are qualified to do minor grammatical cleanup; far fewer are equipped to make particular factual corrections. — Lomn 13:13, 25 April 2007 (UTC)

[edit] Science Competition questions

I have encountered a few questions in a science contest that I dont know. Pls explain and tell me the answers. Thank you. From Invisiblebug590 11:58, 25 April 2007 (UTC)

Apr25$01.jpg

Caption1

Apr25$03.jpg

Caption2

Apr25$04.jpg

Caption3

Apr25$05.jpg

Caption4

Note; the questions are in the pictures and I would like to thank anyone who can solve the questions immediately.

We won't do your homework (or your competitions), but we can give you a few hints. Caption 2 for example: try replacing the weird units with the SI ones (metre, kilogram, second), and then using the formula F=ma to work out the units of F. I don't especially like the last question; they confuse vector (displacement) and scalar (speed) units. Nevertheless, you could try considering the total distance that he travelled, given that even when he is moving backwards, he is still moving. Caption 1 looks pretty simple, but I've got a feeling it may involve nasty logarithms. Laïka 12:14, 25 April 2007 (UTC)

Not answers, but hints:

Q1 - see half-life. You can avoid difficult calculations by noting that 10,00 years is more than 1 half-life, but less than 2.

Q2 - see dimensional analysis.

Q3 - See Laïka's response above. Gandalf61 12:32, 25 April 2007 (UTC)

Can anyone help with the real question in q2: we all know who Kamenev, Zinoviev and Trotsky are, and where Lvov is, but who, where or what is Minokiek? </pointlessness> Algebraist 12:57, 25 April 2007 (UTC)

It could be a corruption of Zinoviev (Z ROT13s to M, and V very nearly ROT13s to K (an exact ROT13 of these letters would be Minoiiei, but presumably they chose K, the nearest Russian sounding letter)). Laïka 13:10, 25 April 2007 (UTC)

Pretty tangential. What was wrong with Molotov? Algebraist 19:42, 25 April 2007 (UTC)

He wasn't a very good bartender for a start; he only knew how to make one cocktail.</bad joke> Laïka 20:59, 25 April 2007 (UTC)

Not even. Like many famous dishes, that one is named after the person for whom it was first made. —Tamfang 02:07, 28 April 2007 (UTC)

[edit] Favorite colors and car colors

I found myself wondering about blue cars the other day. Are they really the most common color of automobile? I wonder if this used to be true but isn't anymore, or is only true in certain areas. That got me wondering whether blue is really the most common favorite color, is that cross-cultural, and what are the "percent favorite" numbers on the other colors? I tried adding an unscientific web study to color (the best I could find by Googling around) but it was removed shortly thereafter. -- Beland 15:16, 25 April 2007 (UTC)

Here in Texas there is a strong dominance of black, white and silver cars - probably 75% of cars on the roads are one of those three - red probably comes next in popularity - but blue isn't anywhere near as popular. If you see a strong dominance for blue in your part of the world then it's probably a regional thing. I did a survey of MINI Cooper owners from the US MINI owner's club back in 2003 - the results are here: http://www.sjbaker.org/telamom/colours.html - but that's a very biassed survey because the people I asked were all car nuts - the results for the general public would probably be a lot different. SteveBaker 21:54, 25 April 2007 (UTC)

I remember an old UK survey (about 10 years ago) that found the most common colour of car was red. So it's most certainly down to regional variations - or observer bias (perhaps you notice the blue cars more - or less - often?). Spiral Wave 12:34, 27 April 2007 (UTC)

'If you buy a blue car, you see blue cars everywhere'

I have the impression that green cars are much more common here (San Francisco Bay) and now than they were in my youth in Illinois. But I did buy a green car in 2002. —Tamfang 02:09, 28 April 2007 (UTC)

Another editor located some North American car color statistics, which have been added to Automakers. -- Beland 02:27, 30 April 2007 (UTC)

[edit] Astronomical question

I have heard about Gliese 581 "super earth". Now I wonder what our earth would look like if it were tidally locked with the sun. 84.160.254.232 17:04, 25 April 2007 (UTC)

Most significantly, the bulk of the sunside would be unlivably hot while the bulk of the darkside would be unlivably cold for humans. There would be a circular band around the terminator which would at least be of approximately livable temperature, and probably livable on the whole. Latitude would be irrelevant to temperature within this band: since the sun is perpetually fixed in one place in the sky, it doesn't matter if you're at 70° lat 0° long or 0° lat 70° long, as it would be a 70° angle either way. I have no idea what the uneven heating would do to the atmosphere near the habitable zone, though my best guess is that air would tend to freeze out on the darkside. The drop in pressure would pull air from the sunside around, causing it to freeze, and eventually resulting in a massive drop in air pressure, possibly to an effective vacuum. If that's the case, nix the whole habitable zone idea. — Lomn 18:50, 25 April 2007 (UTC)

I would have hoped that heat transport with the atmosphere and the oceans would prevent a complete freez out. This, of course, would critically depend on the atmosphere to start with. And wouldn't earth's internally generated heat (potash radioactive decay) prevent a too low drop of temperature? 84.160.254.232 19:26, 25 April 2007 (UTC)

Regarding heat transferred by the atmosphere, it might. I'm not at all certain. However, the Earth's internal heat has virtually no relevance to human habitable temperatures. Any darkside scenario should start with the South Pole's 6-month-long no-sunlight winter and get significantly worse from there. -80 °C is already a common Antarctic winter temperature. —The preceding unsigned comment was added by Lomn (talk • contribs) 20:07, 25 April 2007 (UTC).

These sorts of atmospheric models are still in their infancy, and I think concluding any sort of freeze-out is a bit premature. The models available generally predict a reasonable circulation with (depending on the model/planet) interesting stable areas near the poles. Oceans and atmosphere can both have significant contributions to heat transport, in different systems; atmosphere usually produces strong winds that redistribute heat pretty effectively, oceans provide huge heat sinks that make an established system hard to change. So it might well depend if such a planet had any sort of stable circulation patterns going on before tidal lock set in. Spiral Wave 22:42, 26 April 2007 (UTC)

I remember a program where they set up this scenario. the planet was just the right distance so that the sun lit area was at a perfect temprature. there was a perminate hurrcaine near the center ocean and life was possable. came out on that show Extraterrestrial or something like that. anyways they said the planet would be livable because of the winds and oceans helping move and distribute the temprature. its times like this that i wish i had the money and took the time to order that video or any videos that come out =) User:Maverick423 If It Looks Good Nuke It 20:46, 25 April 2007 (UTC)

It would have only a hurricane or bucket loads of them and other fluid distortions of the atmosphere?Bastard Soap 04:49, 26 April 2007 (UTC)

In the science fiction universe of Larry Niven, Jinx is a tidally locked inhabited planet approximately the same size as Gliese 581 c. Niven has a mathematics degree and the hard science in his stories is usually well researched, so Jinx may be a proxy for conditions on Gliese 581 c. Big difference is that Jinx is a satellite of a gas giant (so, yes, technially it is not a planet) so tidal forces, which affect the shape of Jinx, may not be as significant for Gliese 581 c. Gandalf61 11:18, 26 April 2007 (UTC)

(I've disambiguated Gandalf's link) As I read it, Jinx isn't tidally locked to it's star/heat source, so the extremes there aren't temperature driven, and it still has a day/night cycle. Instead, it's just a range of ridiculous elevation with atmospheric pressures acting there as they would on any other rotating planet. That said, I'm having a hard time figuring out Jinx' orbital orientation from our article and it's been much too long since reading any non-Ringworld Known Space stuff. — Lomn 14:41, 26 April 2007 (UTC)

[edit] Snakes

My teacher and I have been discussing conjoined twins, human and animal. I came up with the following quesiton, "If a snake has two heads, is it one snake with two heads, or two snakes with one body?" --wpktsfs 19:21, 25 April 2007 (UTC)

Two heads, two minds (even if snake minds). So I would say two snakes, as an opinion. But what is the exact definition of "a snake"? 84.160.254.232 19:30, 25 April 2007 (UTC)

Semantics, really, but they are usually descibed as "one animal with two heads". See Polycephaly#One or two animals? Also, if you have enough money, you could buy yourself one [2]. Rockpocket 19:39, 25 April 2007 (UTC)

This also happens with people, and they would be quite upset at being called a "two headed person", I imagine. StuRat 19:44, 25 April 2007 (UTC)

Do they have one vote for an election or two (not quite kidding)? 84.160.254.232 20:18, 25 April 2007 (UTC)

No, because voting rights are generally based on consciousness, not on physical anatomy. You don't lose half you vote if your legs get cut off, either. --140.247.242.222 20:48, 25 April 2007 (UTC)

(Edit conflict) seeing as how its two sepreate thinking minds, it would count as two votes. however getting the privacy for one of them to vote might be a problem as one one person is allowed per booth =) User:Maverick423 If It Looks Good Nuke It 20:50, 25 April 2007 (UTC)

Chang and Eng had 22 children in all, so presumably the privacy issue can be worked out. :) --TotoBaggins 02:46, 26 April 2007 (UTC)

Or their partners were a bit kinky ;) Vespine 04:19, 26 April 2007 (UTC)

We have an article on Abigail and Brittany Hensel who are 17 years old girls with two heads and two arms and two legs and one trunk containing two backbones and two hearts. They each had to pass the driving test to get their drivers licenses, even though each controls one hand and one foot. Clearly two remarkable and admirable people, so each would get to vote or to serve on a jury, and each will get a diploma when they finish high school. Edison 04:34, 26 April 2007 (UTC)

I have a question. If an adult male marries Abigail and Brittany Hensel then will he be guilty of polygamy? If he marries just one of them then will he be commiting adultery? 202.168.50.40 05:51, 26 April 2007 (UTC)

Ok now that is a tricky question. since they both have individual minds, but the same torso, im not sure if it will be consisdered adultery. maybe they have to find a guy that loves both of them but that might also count as polygamy. i hope someone might have a better awnser to this as i am now courius to know too. User:Maverick423 If It Looks Good Nuke It 16:01, 26 April 2007 (UTC)

Their article says they had to take their driving test individually, though obviously both had to take part on each occasion. I guess one could take this is a precedential law with regards to your question. So an individual could marry either of them independent of the other (even though the other would have to be involved physically) because there is a legal precedence that they can identify their shared body as representing one or the other (as they must have done when they turned up for their driving test). Similarly, one could argue adultery would not be an issue for the same reason (though I wouldn't advise discussing that issue in detail per WP:BLP.) Rockpocket 19:53, 26 April 2007 (UTC)

Wow. Lots of thought. --wpktsfs 19:35, 26 April 2007 (UTC)

Ok so then lets say they marry diffent men then. would it be cheating since its just one body? how would that work and wouldnt the men get into a big fight over all this? User:Maverick423 If It Looks Good Nuke It 22:39, 27 April 2007 (UTC)

[edit] biotech

where can i find detailed entreprenuer project reports for starting up of a biotechnology company?please please help me find it.. i desperately need to see some sample reports. —The preceding unsigned comment was added by 59.95.193.184 (talk) 19:57, 25 April 2007 (UTC).

cant any1 please help me.. please..

you might have a better chance of googling this. we dont have such reports like this to help you. check busness websites and ask there its your best chance at finding what ur looking for. User:Maverick423 If It Looks Good Nuke It 16:03, 26 April 2007 (UTC)

i m totally cluless about this.. can you atleast suggest me some business sites where i may find it??

Cnn has a busness site that talks about the latest busniess news and gives pointers to starting your own. now i dont mean to sound rude or anything but as a Entreprenuer, your ganna have to find your own way because there are very few, if any, people that will help you. its just the way the world works i learned that the hard way =). User:Maverick423 If It Looks Good Nuke It 17:08, 26 April 2007 (UTC)

thanks for the help and concern.. i really appreciate it..

[edit] Hydrogen Sulfide

As I understand it, Hydrogen sulfide is a very dangerous gas because it is toxic and highly flammable. It's hard to detect because it deadens the sense of smell. Is that effect unique to humans? Would an animal such as a dog or canary be able to detect the gas reliably as it neared the level dangerous to humans, or was it impossible to detect reliably before the invention of gas detectors? Shui9 20:53, 25 April 2007 (UTC)

if i remember correctly, they used birds to detect for leathal levels of gasses in coal mines. the bird would die which ment the gas levels are approching deadly which signaled he workers to high tail it out of there. i would assume a bird might be used the same way in this situation.User:Maverick423 If It Looks Good Nuke It 20:58, 25 April 2007 (UTC)

The coal mining gas is not hydrogen sulfide but carbon monoxide or methan (cant remember which). Any sensible human (especially with olfactory sense) would be driven fast, far and long by hydrogen sulfide long before it reaches critical concentrations. 84.160.254.232 22:02, 25 April 2007 (UTC)

In the lab you smell it and it gets really bad and than you simply dont smell it any more and this is the clear point were you should get fresh air. So its difficult to get poisoned by it, but if you have no place to go like in a vulcanic crater or so than you loose your life. But CO and CO2 are more deadly because you dont smell them at any point.--Stone 22:11, 25 April 2007 (UTC)

Just a small point: the air hunger you feel when holding your breath is due to increased CO2 levels, not decreased O2 levels. You can't smell CO2, but you'll be desperate for fresh air when it reaches lethal levels. On the other hand CO can kill painlessly because it doesn't cause the victim to gasp for air. --Bowlhover 23:12, 26 April 2007 (UTC)

This is why Nitrogen is so dangerous. You can asphyxiate on Nitrogen as it doesn't cause people to gasp even as O2 levels are reduced to near zero. --Tbeatty 16:19, 28 April 2007 (UTC)

[edit] Clotted Cream?

I've left heavy cream in my fridge, unopened, for months, and then opened it to find that at least the top portion has hardened into something similar to butter, but much more white and creamy. Super yummy. Has an almost gummy texture. The question is a) why this happens, and b) how I can get it to happen whenever I want. Does it have something to do with ultrapasteurization? With especially cold temperatures? With letting it sit past the due date? Is it just luck? THanks, 70.108.216.222 21:07, 25 April 2007 (UTC)

If you like clotted cream, you're probably best off buying it rather than trying to make your own. - Nunh-huh 02:53, 26 April 2007 (UTC)

Yea, whey better off. StuRat 04:55, 27 April 2007 (UTC)

Why it happens is that the little droplets of butter fat making up the cream float as they are lighter than water, gradually they move up to the top and stick together. If you want to make it I suppose you could centrifuge the cream longer to condense the cream. GB 06:01, 27 April 2007 (UTC)

[edit] I need to learn a lot about dwarfism fast--

I need to know who and how it affects the person, symptoms and conditions, possible causes, the body that it affects, survival rates, treatments. i know thats a lot to ask,.... but thanks a lot!! —The preceding unsigned comment was added by 75.47.76.243 (talk) 23:47, 25 April 2007 (UTC).

Not suprisingly, the article on Dwarfism covers this subject. -- Diletante 23:53, 25 April 2007 (UTC)

Thats the best place to look. --wpktsfs 23:54, 25 April 2007 (UTC)

Yep, you'll rarely come up short at Wikipedia. StuRat 04:50, 27 April 2007 (UTC)