Wikipedia:Reference desk/Archives/Science/2006 September 29

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magnetic north

Please explain in a concise sentence the diffrence between magnetic north and true north. Thank you! :-) —Preceding unsigned comment added by 24.241.22.219 (talk • contribs)

Magnetic north is where compasses point; true north is on the axis of the Earth's rotation. --Allen 00:51, 29 September 2006 (UTC)[reply]

See this for a more detailed explaination. And don't forget to sign your comments with four tildes: ~~~~ Dar-Ape (talk) 00:57, 29 September 2006 (UTC)[reply]

leptin???

can i buy this anywhere??? my doctor thinks this would be a good thing for me to take but how to buy??? thanks bruce woolley phone phone number deleted

email address deleted

You know what would be cool - a website that is sort of a wiki and sort of an encyclopedia. I know, we could call it something like Wikipedia. And then, there could be articles on it about things like leptin and people can describe what it is and include links in the article to people who hawk garbage like leptin as a miracle weight loss pill. --Kainaw ^(talk) 02:10, 29 September 2006 (UTC)[reply]

Ah, but if someone started up this crazy "Wikipedia" you speak of, then it would compete with Wikipedia and we'd be forced to destroy it like all the others. Melchoir 02:24, 29 September 2006 (UTC)[reply]

what about this one [1]? Xcomradex 04:14, 29 September 2006 (UTC)[reply]

Black Ops isn't interested in eliminating Uncyclopedia; we have our reasons. Melchoir 04:34, 29 September 2006 (UTC)[reply]

i for one find its coverage far more accurate (eg. [2], its definetely this first place i look for actual info. Xcomradex 04:49, 29 September 2006 (UTC)[reply]

Ah, but we've got a much more comprehensive catalog of Pokemon. Melchoir 04:59, 29 September 2006 (UTC)[reply]

touche. Xcomradex 06:11, 29 September 2006 (UTC)[reply]

C'mon guys, try to make an effort to be at least pretend to be nice to the new folks. – Clockwork Soul 06:15, 29 September 2006 (UTC)[reply]

We even have a nice template I created for this use now! Template:Refq If not for us, for the newbies. — X [Mac Davis] (SUPERDESK|Help me improve)07:14, 29 September 2006 (UTC)[reply]

If you have a weight problem, the chances are at least 99.99% that you already have more leptin than most of us and do not need more. Leptin is produced by fat tissue and serves as a signal to the brain that you have plenty of fat (a different signal than looking in the mirror). In an ideal world, this signal would result in less eating. However, the leptin signal, like looking in the mirror, often does not make a large change in eating behaviors. Injecting more leptin might be less effective than posting a picture of yourself on your refrigerator as a signal to your brain that you have more fat than you need and should eat less. When leptin was first discovered in the early 1990s it was found that mice who were genetically deficient were obese and if they were given leptin injections they lost weight; as you can imagine, pharmaceutical companies invested enormous amounts of money into leptin research until it was clear that leptin deficiency is such a rare cause of human obesity that less than 10 cases have been found and that leptin injections do nothing for people who already have plenty of leptin (the rest of us). alteripse 07:18, 29 September 2006 (UTC)[reply]

Rib Removal: 11th and 12th: Why?

Is removal of ribs 11 and 12 possible and why would one do so? What is this procedure called?70.242.47.227 03:22, 29 September 2006 (UTC)Dominique[reply]

I can't find the name of the procedure, but it may help you accomplish a frontbend. freshofftheufo ΓΛĿЌ 05:16, 29 September 2006 (UTC)[reply]

There's a snopes page about rib removal. - Rainwarrior 05:21, 29 September 2006 (UTC)[reply]

I believe it helps women or gay men get the "wasp waist" shape, which is considered by many to be beautiful. StuRat 08:49, 29 September 2006 (UTC)[reply]

One hopes that this is a (bad) joke.--Deglr6328 13:41, 29 September 2006 (UTC)[reply]

I wish it was. StuRat 17:22, 29 September 2006 (UTC)[reply]

Prince (musician) was meant to have had some ribs removed so that he could bend down and suck his own penis more easily. --84.65.99.86 11:35, 29 September 2006 (UTC)[reply]

People say the same thing about Marilyn Manson, but he says it's bullshit. freshofftheufo ΓΛĿЌ 11:42, 29 September 2006 (UTC)[reply]

Read the Snopes page. It's all just urban legend. – Clockwork Soul 16:40, 29 September 2006 (UTC)[reply]

Ribodectomy?--Light current 20:32, 29 September 2006 (UTC)[reply]

A rib resection of the 11th and/or 12th ribs is sometimes carried out to allow surgical access for a nephrectomy, either due to renal cancer or because the patient is donating it. (The first rib may be resected in thoracic outlet syndrome.)Mmoneypenny 18:28, 30 September 2006 (UTC)[reply]

Albratrosses and gulls

How closely related are they?

They are both of class aves. See albatross and gulls. freshofftheufo ΓΛĿЌ 11:43, 29 September 2006 (UTC)[reply]

The Sibley-Ahlquist taxonomy lumps them together in a new, greatly enlarged order Ciconiiformes. "New" here apparently means that the old term has been given a new meaning. --Lambiam ^Talk 13:30, 29 September 2006 (UTC)[reply]

Interesting! Note to anyone still reading: The new definition is not uncontested. freshofftheufo ΓΛĿЌ 13:32, 30 September 2006 (UTC)[reply]

prince was abused as 4 year old

Daleks vs Magpies vs Gulls

3 vintage RD topics, all fighting it out, who wins?--172.163.55.148 12:34, 29 September 2006 (UTC)[reply]

the bagel whips them all.Xcomradex 13:15, 29 September 2006 (UTC)[reply]

Moles are kings of the undergorund 8-)--Light current 16:32, 29 September 2006 (UTC)[reply]

Daleks, really? Must be before my time. Melchoir 23:05, 29 September 2006 (UTC)[reply]

Your time doesn't stretch back more than a few days I guess? Daleks even flying ones have appeared on television pretty recently and we have some great articles on those episodes and a featured article called Dalek. - Mgm|^(talk) 23:19, 30 September 2006 (UTC)[reply]

Yes yes, but on the reference desk? Melchoir 18:01, 1 October 2006 (UTC)[reply]

Well, they all fly... Ah, magpies can pick things up, even gulls, and Daleks can't, so... -- Fuzzyeric 00:26, 30 September 2006 (UTC)[reply]

Who wins? Easy. The first one to travel faster than light wins! Mattopaedia 09:06, 30 September 2006 (UTC)[reply]

if you want the gull to win, just drop your sandwich Mattopaedia 09:09, 30 September 2006 (UTC)[reply]

By my perception, Daleks can't fly. Daleks have trouble with stairs. However, there's something to be said for death rays. --Amanaplanacanalpanama 22:49, 30 September 2006 (UTC)[reply]

Daleks most certainly can fly. Watch any of the Dalek storylines in the two most recent series of Dr Who for confirmation. We also see one flying up a flight of stairs in the Sylvester McCoy era Dalek episodes... --Kurt Shaped Box 22:54, 30 September 2006 (UTC)[reply]

Whoever wins - we lose. --Kurt Shaped Box 10:15, 30 September 2006 (UTC)[reply]

Kurt Shaped Box is right on the money. They can all fly, but unless the doctor is around magpies and gulls would be exterminated. Daleks win, we lose. - Mgm|^(talk) 23:19, 30 September 2006 (UTC)[reply]

Nuclear density

Is it true that basically all (atomic) nuclei have roughly the same density? I heard it once from a fellow undergrad physicist, and it sounded strange but plausible. I could go off an calculate the densities of every element's nucleus, but to be frank I cannot be bothered if someone can give me an answer here quicker. Thanks in advance Batmanand | Talk 12:50, 29 September 2006 (UTC)[reply]

Since nuleii are only composed of neutrons and protons then if the densities of neutrons and protons are te same, then the idea is plausible. Looks like they are the same density from our pages on them. --Light current 16:42, 29 September 2006 (UTC)[reply]

If you use the formula provided in Atomic nucleus#Nucleus size for calculating the densities, you will come up with almost exactly the same value for each element, simply because, according to that formula, the size is proportional to the mass number, and the mass of a nucleus is an almost constant factor times the mass number. I have no idea how the size of a nucleus would actually be measured, and how good an approximation that formula is. --Lambiam ^Talk 16:58, 29 September 2006 (UTC)[reply]

Yes, as far as I remeber from my own undergrad time, that's correct: the density of nuclear matter is roughly idepend of the atomic species. I'm not sure about the reason but I'd venture the guess that it has to do with asymptotic freedom, which makes the strong force increase with distance and hence keeps the quarks in the nucleons together, but not too tightly as on these minute distances, the force becomes weak. Also, the Yukawa coupling keeps the nucleons quite tighly together. On the other hand, however: The nucleons are not in close-packing, but organized as described by the nuclear shell model. It is also quite difficult to define the radius of a nucleus (or even of a nucleon) and hence to give an exact meaning to the term "nuclear denisty". If you define the diameter of, say, a proton, via the Fourier transform of the result of a scattering experiment in a collider, you get differet results whether you scatter off accelerated electrons or protons. Hence, there is an "electromagnetic" and a "strong force" radius. Also, I now remeber that some nucleii do deviate from the constant density rule quite noticeably, and rather recent research associates this to the idea of nuclear halos, i.e. hollow shells of nuclear matter surrounding the core part and leaving some empty space between inner nuclear core and halo. Now, as I pulled all I remember from the back of my head, your "homework": Research the details of this stuff and expand it to our nuclear halo article which has only two lines su far. Simon A. 21:57, 29 September 2006 (UTC)[reply]

Nuclear Fusion

If one of the goals of nuclear fusion is to create more energy than is consumed, then how is it possible for fusion to ever be a reality? Doesn't that violate some laws of thermodynamics or something? A Clown in the Dark 15:35, 29 September 2006 (UTC)[reply]

No, the idea is to convert energy from one type to another, not to create it. There is an energy barrier though, which may be what you mean.In that case, if the energy in is less than the energy out, all it means is that the fusion reaction is exothermic, with more of the energy in the nuclei being converted to heat than the amount of energy required to allow the reaction to take place. No enegry is created, just some converted. 80.169.64.22 15:53, 29 September 2006 (UTC)[reply]

In nuclear fusion mass is converted to energy according to Einstein's famous equation E = mc². The law of thermodynamics commonly called "conservation of energy" might more appropriately be called "conservation of mass-energy" or even just "conservation of mass" (since energy E has mass m = E/c²). --Lambiam ^Talk 16:44, 29 September 2006 (UTC)[reply]

Have you read the article on fusion power? It should answer most of your questions about how nuclear fusion would work as an energy source. — QuantumEleven 17:15, 29 September 2006 (UTC)[reply]

Hah! I knew stars were just lumps of burning coal. Clarityfiend 17:26, 29 September 2006 (UTC)[reply]

Seriously though, a team at UCLA has initiated fusion using a tabletop machine, though it still takes more energy than it produces ([3]). Clarityfiend 01:02, 30 September 2006 (UTC)[reply]

Size matters here. The bigger it gets the easier it will be to maintain the necessary temperatures to keep the fusion going. The present setups are just for experimentation. Building the first productive one will cost loads, so it makes sense to first make sure you build something that will work. Alas we don't quite have the time to wait until we have the knowledge to build the 'perfect' reactor at the first attempt. Also alas, the money spent on this is a fraction of the money spent on fossil fuels (largely finding them, I suppose). DirkvdM 11:42, 30 September 2006 (UTC)[reply]

I think the simple answer to A Clown in the Dark's question is that it is just a confusion of terminologies. For the most part it is a question of getting out more power than you put in, not more energy. With fusion power reactors like the JET tokamak it take a considerable amount of electrical power to operate the reactor and heat up the plasma to the point at which fusion can occur. Once fusion starts, the reactor begins to generate power via mass conversion as Lambiam says. Fusion researchers want to at least breakeven and measure the ratio between the power generated and the power needed to heat the reactor. This is known as the Fusion energy gain factor or Q but it does not count the energy contained in the mass of the Deuterium-Tritium fuel that is consumed. -- Solipsist 14:36, 3 October 2006 (UTC)[reply]

Case of the Missing Printhead

From where might I get a Canon S500 printhead? I bought a printer off eBay that said the printhead wasn't included - I thought printheads where part of the cartridge but I guess it depends on the printer. I can use the printer until I locate the printhead. Any idea why someone is selling printers in which the printhead has been removed? --Username132 (talk) 15:54, 29 September 2006 (UTC)[reply]

To have a joke on unsuspecting people? 8-)--Light current 16:39, 29 September 2006 (UTC)[reply]

As others have stated you can have buy printheads new (if they're still available) although it would make little sense given the cost. However it's easily possible people would have some around for whatever reason (e.g. printer died print heads okay). Since the person clearly specified it didn't have a printhead, I would suggest it's username's fault for not properly researching before buying. Nil Einne 04:01, 30 September 2006 (UTC)[reply]

It was probably damaged or lost. Then, they found they couldn't buy one anywhere, so they decided to sell the printer. StuRat 17:08, 29 September 2006 (UTC)[reply]

Caveat emptor !--Light current 17:11, 29 September 2006 (UTC)[reply]

I just did a Google search on "canon s500 print head" and found many sites that will sell you one, so you're in luck ! StuRat 17:13, 29 September 2006 (UTC)[reply]

I had the print head die on a Canon S300 a while back (at least with the 300 the head was a separate unit, into which you'd plug the ink carts). The cost for a new print head was such a large proportion of the cost of the entire printer (I think a new head was about £50 and the printer had only cost about £80) that the only smart thing to do was dump the entire printer and buy a cheap laserprinter (it was a pretty duff printer to begin with, with slow, pretty crummy prints and a tendency for the heads to dry out). -- Finlay McWalter | Talk 22:47, 29 September 2006 (UTC)[reply]

Bathing after meals

Ppl use to say not to bath right after meals, why? is there any scientific support?

Swimming is an extremly physical sport, recquiring a lot of blood supply to alomost all muscles, which diverts it from the gut, which as a result recieves minimal blood supply, so if it has more food that it can cope with given the energy provided (the oxygen in blood is recquired for energy release) then it will jettison some of the food. I.e. you'll throw up. Philc _T^E_C^I 18:45, 29 September 2006 (UTC)[reply]

I never thought of that... now it all makes sense! --Russoc4 19:04, 29 September 2006 (UTC)[reply]

It makes sense, but it doesn't actually happen... I've never seen someone throw up just because they ate dinner and then went swimming, or even swam in a raceXcfrommars 19:10, 29 September 2006 (UTC)[reply]

I've thrown up beofre for over exerting myself over a meal, and I know other people have (though not specifically swimming, but the principles the same), you will feel a lot of butterflies prior to it happening, as this is caused by lack of blood supply to a full stomach aswell. Philc _T^E_C^I 20:48, 29 September 2006 (UTC)[reply]

Before taking martial arts classes we were told not to eat a large meal, as your digestive system will take energy to digest it, and there would be a possibility that you would pass out, since there isn't enough oxygen/energy to go around. Of course, we were also told to eat SOMETHING (like an apple) to provide us with some energy for practice. --Bennybp 21:29, 29 September 2006 (UTC)[reply]

The reason they suggest it is that you are likely to experience painful cramps when exerting yourself shortly after eating a meal (for the blood supply issue stated above) and if you panic as a result, and are in deep water, you could potentially drown. --Jmeden2000 19:55, 29 September 2006 (UTC)[reply]

Swimming was sometimes thought risky after a meal, but bathing was ok, especially if the person was a messy eater.Feed the baby, then bathe the baby. Then bathe the parent. Edison 20:26, 29 September 2006 (UTC)[reply]

Hmm, maybe that tryptophan and energy required for digestion combined with the warm, soothing water would cause undesirable effects. Hyenaste ^(tell) 21:36, 29 September 2006 (UTC)[reply]

Swimming just after eating is likely to cause side stitch. —Keenan Pepper 21:52, 29 September 2006 (UTC)[reply]

Try reading what Snopes has to say about this urban legend: [[4]] Rmhermen 00:38, 30 September 2006 (UTC)[reply]

Do or do not. There is no try. freshofftheufo ΓΛĿЌ 13:22, 30 September 2006 (UTC)[reply]

Snopes is right, it's not dangerous, but it does hurt when it happens. —Keenan Pepper 17:01, 30 September 2006 (UTC)[reply]

How much pot is too much?

Is a 20-spliff-a-day habit bad for you in the long term? --84.66.42.217 22:13, 29 September 2006 (UTC)[reply]

See our article on Cannabis, but note our content disclaimers. JBKramer 22:14, 29 September 2006 (UTC)[reply]

I think everybody knows what it does. Smoking it by itself does not cause any physiological harm, however it affects your thinking and judgement, as well as making you a lazy slob. — X [Mac Davis] (SUPERDESK|Help me improve)23:16, 29 September 2006 (UTC)[reply]

Will your buddies really want to hang out with a lazy, fat, permanently-stoned hippy? I dunno - maybe all your buddies *are* lazy, fat, permanently-stoned hippies? ;) --Kurt Shaped Box 23:37, 29 September 2006 (UTC)[reply]

You might get lung cancer one day? Though if you smoke 20 spliffs a day, you probably don't care about that. :) --Kurt Shaped Box 23:33, 29 September 2006 (UTC)[reply]

Yes, smoking pretty much anything will cause lung cancer, since lungs aren't made to handle much inhaled smoke. StuRat 00:12, 30 September 2006 (UTC)[reply]

I'd say that smoking pretty much anything can cause lung cancer. Not to mention mouth cancer and throat cancer. It won't necessarily happen to you, but then again it just might. It's a huge risk, not worth taking. JackofOz 00:17, 30 September 2006 (UTC)[reply]

I have never personally researched it. I bet there is a strong correlation but does that imply causation? — X [Mac Davis] (SUPERDESK|Help me improve)02:32, 30 September 2006 (UTC)[reply]

In this case, yes. One obvious requirement is that the "cause" occurs prior to the "effect", which is true here. Another requirement is that there be a mechanism for the cause to produce the effect. The presence of numerous carcinogen chemicals in tobacco smoke is a known mechanism for causing cancer. There is also a lack of alternative explanations for the correlation. StuRat 05:08, 30 September 2006 (UTC)[reply]

How do the carcinogens work than? I would guess we don't know that well, since we don't know where cancer comes from. I am pretty much skeptical because we seem to be missing a vital link in the chain of events. It isn't just smoke>cancer. — X [Mac Davis] (SUPERDESK|Help me improve)08:14, 1 October 2006 (UTC)[reply]

I think people put way too much weight on the few people who never get cancer as a result of their smoking, for the simple reason that it's in their genes. Actually, this comment leads into loads of instigations involving big tobacco companies and greedy politicians, so I'll revoke it until I'm ready to push my opinions about all that other stuff too. freshofftheufo ΓΛĿЌ 13:15, 30 September 2006 (UTC)[reply]

Yeah kids - don't smoke. It's a bad habit and it's not big, hard or clever (says I, with the 30th cigarette of the day danging from my mouth as I type). --Kurt Shaped Box 00:24, 30 September 2006 (UTC)[reply]

By spliff do you mean a joint that is a mix of cannabis and tobacco? If so then the known health risks of tobacco use make it bad. If it is just weed, from personal experience it would prob make you slow in the head for awhile. Depends on the potency of the weed. I say go ahead. just dont try and go anywhere. Sosobra 03:32, 30 September 2006 (UTC)[reply]

Cannabis smoke has been found to be worse for you than tobacco, cancer-wise. This might be because cannabis smokers tend to inhale deeper. —Pengo ^{talk · contribs} 11:10, 30 September 2006 (UTC)[reply]

But nobody "chain smokes" cannabis like people do with tobacco, so the total effect on the lungs is far less. StuRat 12:14, 30 September 2006 (UTC)[reply]

There are a number of obvious reasons, and inhalation depth is the least easy to prove. Cannabis is often in a much more potent form than any tobacco you can buy in the western world, which can mean a few things, mainly additional (unhealthy) chemicals. There is also no filter on (most) people's spliffs, so they're getting the full blast from the smoke. freshofftheufo ΓΛĿЌ 13:19, 30 September 2006 (UTC)[reply]

But tobacco contains a host of chemicals added by the cig companies to make them more addictive, as well as all the unintended chemicals, like pesticides. Since tobacco additives are completely unregulated and unreported, the public doesn't really know what's in them. StuRat 23:53, 30 September 2006 (UTC)[reply]

Something that I wish I had known before know. What a pethetic thing this is we call "democracy". freshofftheufo ΓΛĿЌ 06:19, 1 October 2006 (UTC)[reply]

It is incredible how many people have missed the essential part of the question. Everyone jumps on the bandwagon of indoctrination saying that "smoking is bad for you". Mac Davis even makes the classic mistake of saying that "everybody knows that". But the question was how bad it is to smoke 20 spliffs. That is not only an essential aspect that is usually missed, but it was even actually the question here. And still everyone misses it (except Kurt). That said, I can't answer the question either, in part because I don't know what kind of weed it is (there is a huge variation), how big the joints are and if yo mix with tobacco. Buit if you smoke big joints fille dpurely with Dutch quality weed, never mind your lungs. You're messing up your brain. Bad lungs will make you live shorter. Bad brains will make you miss what life you have, which is much more important 9another important aspect that is often missed). DirkvdM 18:59, 2 October 2006 (UTC)[reply]

Largest sensor size in compact digital cameras

Are there any compact digital cameras available which use (physically) large sensors? In point and shoot camera it says that "The sensor used in these types of cameras tends to be smaller than their SLR counterparts", but does not mention any exceptions. Sony Cyber-shot DSC-R1 mentions the use of an APS-C sensor in this 2005 camera, and says it's the first time it has been used in a non-DSLR camera. Have any other non-SLR cameras used this sensor since? I'm interested in any information on digital cameras which could legitimately be called compact (ie. a couple of inches thick when closed, not a giant like the Sony above; I'm not counting the Leica M8 as a compact either!) which use a larger than normal sensor. Digital photography lists a number of sensor sizes between 1/2" and 4/3", but doesn't give any examples of where they are used. Thanks. CarelessHair 23:45, 29 September 2006 (UTC)[reply]

See this blog post for a good discussion about why this isn't done. --203.214.55.189 02:04, 30 September 2006 (UTC)[reply]

top of the world?

Answered

Hello there ,

my question is so simple ? where is the top of the world is it the north pole or the souh or nither of them ?

Ahmed salah

thanks of your time

Neither. StuRat 00:07, 30 September 2006 (UTC)[reply]

In space, no-one has the right to tell you which way is 'up'. --Kurt Shaped Box 00:10, 30 September 2006 (UTC)[reply]

You could say Mount Everest, though. If up is away from the center of the earth, the peak of Mount Everest would be the most up, and perhaps you could call that the "top". --Allen 00:18, 30 September 2006 (UTC)[reply]

Except that Everest isn't the farthest point from the center of the Earth. The equatorial bulge means that Chimborazo (volcano) is the farthest from the center, according to Extreme points of the world. Rmhermen 00:30, 30 September 2006 (UTC)[reply]

Thanks, Rmhermen; that's both a good fact and a good article to know about. It's cool to see that the land and sea poles of inaccessibility are almost exactly the same distance away from their respective land/sea borders. --Allen 02:10, 30 September 2006 (UTC)[reply]

What Kurt is trying to tell you is that "up" or "down", in the context of maps of the world, is arbitrary. There's no reason why you couldn't draw perfectly accurate maps which have the south pole at the top, or any other point on the earth (though for navigation purposes it makes good sense to put the poles at the top).

Consider that you're floating in space on the edge of the solar system. You get out your telescope and look at the Earth. Relative to your current orientation, everything looks normal, with the north pole at the top of your view.

Then you fire the retrorockets in your space ship a little, so you spin 180 degrees. Now the south pole is at the top. Then you spin yourself another 90 degrees, and a point on the equator looks like it's at the top from your point of view!

Why put the northern hemisphere at tht top of maps? It's probably got a lot to do with the fact that the societies responsible for the first "conventional" maps (as distinct from the string maps of the Polynesians) were all based in the northern hemisphere. --Robert Merkel 00:56, 30 September 2006 (UTC)[reply]

In fact, see the article Reversed map for world maps with south (or something else than north) on top. The very term "reversed" implies a non-neutral point of view, of course. --Lambiam ^Talk 01:03, 30 September 2006 (UTC)[reply]

Actually one thing that the article fails to mention is that the Greenwich meridian is of course completely. arbitary. Others such as the Paris meridian were used historically. While it makes sense to have the international dateline dissecting primarily in the ocean, it could of course be the Atlantic rather then the Pacific. One advantage with having north as up is that east is left. Together with the (completely arbitary) cartesian coordinate system this means east is positive. It makes sense that east is positive due to the rotation of the earth (think why east timezones are positive)... Nil Einne 03:31, 30 September 2006 (UTC)[reply]

One advantage with having north as up is that east is right. Peter Grey 15:27, 30 September 2006 (UTC)[reply]

Note that the North\South direction we use in maps is used because that's the axis which the Earth spins around itself. ☢ Ҡi∊ff⌇↯ 04:03, 30 September 2006 (UTC)[reply]

I suppose the "top" could be the point on Earth furthest from the Earth's orbital plane about the Sun, as well. This would put it on the Arctic circle or Antarctic Circle, at a different point on the circle depending on the time of day. StuRat 04:59, 30 September 2006 (UTC)[reply]

Magnetic North and South Poles could also be used. StuRat 04:59, 30 September 2006 (UTC)[reply]

If you were to place the Earth on a large enough table, it might have an "up". —Pengo ^{talk · contribs} 11:05, 30 September 2006 (UTC)[reply]

Or, alternatively, if you put the Earth through a vertical wind-tunnel test, it would presumably orientate itself into some sort of "upwards" position. freshofftheufo ΓΛĿЌ 13:08, 30 September 2006 (UTC)[reply]

How do you define "vertical" and "up" for your wind tunnel? --Lambiam ^Talk 14:57, 30 September 2006 (UTC)[reply]

If the guy has the technology and power to build a planetary wind tunnel, I wouldn't really argue with him, heh ☢ Ҡi∊ff⌇↯ 18:18, 30 September 2006 (UTC)[reply]

True! But for the record, since we always head into the wind, and cut through the wind head-first, I would choose the head as the top of my planet. freshofftheufo ΓΛĿЌ 06:18, 1 October 2006 (UTC)[reply]

When I'm in a really good mood, the top of the world is wherever I am. DirkvdM 19:30, 1 October 2006 (UTC)[reply]