Wikipedia:Reference desk/Archives/Science/2010 January 29

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January 29

Bismuth

The article on bismuth says that it is more or less nontoxic. However, its only naturally occurring isotope decays into thallium, which is highly poisonous. Why isn't bismuth dangerous to handle as a result? --75.40.204.186 (talk) 01:23, 29 January 2010 (UTC)

It's half life 1.9 × 10¹⁹ years. Do you have any idea how long that is? Dauto (talk) 01:35, 29 January 2010 (UTC)

That's until half of it's thallium. Wouldn't a small amount of it be thallium before then? --75.40.204.186 (talk) 01:39, 29 January 2010 (UTC)

Well the question is then, is thallium harmful in extremely miniscule amounts? 219.102.221.49 (talk) 02:03, 29 January 2010 (UTC)

No, you don't understand - 1.9x10¹⁹ years is an amazingly long time - that's about a billion times the life of the universe! Even if that lump of Bismuth has been around since the literal dawn of time - the amount of thallium in there would be so small, it would be hard to measure. SteveBaker (talk) 02:33, 29 January 2010 (UTC)

Even if the thallium has accumulated over the last 5 billion years the concentration of thallium in bismuth is about 2.6*10^-10 - so even if you eat (?) 100 milligrams of bismuth you eat only 26 picograms of thallium - now what is the concentration of thallium in ordinary tap water? This abstract talks about several measurements, e.g. from not detected up to 8.4 nanograms/liter for Arctic snow. The natural background is estimated at 0.02 to 0.03 picograms/gram (20 to 30 picograms/liter) for the Arctic - so our 100 milligrams of bismuth won't hurt more thallium-wise than a liter of water from pre-industrial Arctic snow. Icek (talk) 06:30, 29 January 2010 (UTC)

Bacteria hitchhiking on manmade sattelites?

With planets like Mars or moons like Titan, we can't yet prove the non-existance of native primitive life, or "prebiotic organic goop", though we probably will in the near future. I'm just wondering if there isn't a chance that hardy bacteria/biochemicals from Earth may contaminate the surfaces of said planets/moons, assuming that some of the minerals and elements fundamental to life actually exist on their surfaces. It seems likely that, just as has happened on Earth countless times, an Earth (large and relatively welcoming and abundant source of life, thus allowing extremely varied forms to evolve) born micro-organism would be more likely to survive and wipe out an extra terrestrial (assuming a place like Mars or Titan, relatively unforgiving and unlikely to form varied or complex life) micro-organism due to the differing conditions of life.

Should I not be worried about that for some reason? Thanks! 219.102.221.49 (talk) 02:00, 29 January 2010 (UTC)

Yes, this has been worried about by serious people. The Mars lander was sterilized before being shot up into space to avoid this kind of problem. (And also to avoid accidentally detecting life... that it had brought with it.) I suspect—but do not know for a fact—that anything that is sent out of Earth orbit (a limited number of things) is probably sterilized first for this reason. Most manmade satellites run no risk of landing on other planets. This article though says that with the Voyager mission, for example, the craft itself was sterilized, but the upper stages of the rockets were not, and they are spinning around out there, somewhere, maybe with bacteria on them. Which is kind of non-ideal. --Mr.98 (talk) 02:10, 29 January 2010 (UTC)

This question, or ones similar to it, is asked about every 6 months or so. If you go through the archives, you should be able to find more info. Dismas|^(talk) 02:12, 29 January 2010 (UTC)

Ah, ok sorry, I usually check but I didn't think to this time around. Thanks for the answers! 219.102.221.49 (talk) 02:18, 29 January 2010 (UTC)

In the early years of space exploration, it was assumed that the harshness of the environment of space would "obviously" kill anything that might be alive on the craft. However, when the Apollo 12 moon walkers visited the site of Surveyor 3 an earlier robotic landing and brought back one of the cameras - it was a considerable surprise to discover that bacteria were still alive on its surface - although this report has been disputed (Reports of Streptococcus mitis on the moon). Either way, that shocked NASA and since then, spacecraft that are to land on other bodies in the solar system are carefully sterilized before launch. But even without that - it seems very unlikely that earthly bacteria released into what would certainly be an exceedingly hostile environment could out-perform the native species that would (presumably) have been living and evolving there for a billion years or more. Even if our own bacteria could survive there, a truly alien species would be so spectacularly different to anything we've ever seen that there would be no mistaking them from earthly lifeforms that escaped into their environment. Another strong possibility is that if there were someplace in the solar system where earthly bacteria could thrive in - then the very rare rocks that travel between bodies in the solar system would already have placed life from from any life-bearing body onto every other life-compatible body many times over the past few billions of years. Remember - rocks blasted from the surface of both Mars and the moon have been found just lying around right here on earth. If bacteria could survive in a hard vacuum alternately baked and frozen on the surface of the moon - then surviving a trip to Mars would be a walk in the park. SteveBaker (talk) 03:32, 29 January 2010 (UTC)

Two points here: I'm not 100 percent sure but I think Darwin would disagree with you on your point about earthly microbes not being able to compete with native microbes. On Earth, organisms highly adapted for specific environments (e.g. isolated islands) are extremely vulnerable to changes in fauna, and in cases where whole faunas evolve separately (e.g. northern and southern hemisphere arctic/temperate fauna), the tendency is for the larger to out-perform the smaller when they have a chance to meet. I don't see why organisms that were even more different wouldn't apply to these same principles. Then I guess the problem isn't that we wouldn't have trouble identifying the microbes as our own, but that our microbes would start to take up niches and to wipe out the native life! 210.254.117.185 (talk) 13:47, 29 January 2010 (UTC)

Or that life could be so spectacularly primitive that it couldn't compete with the bacteria. Think European powers colonizing during the 15-17th centuries.--92.251.222.63 (talk) 00:49, 30 January 2010 (UTC)

Only if they compete for the same thing, though. A truly alien life form would presumably be a lot more different and may hence use different resources. The difference in conditions between Mars and the Earth are also a lot more different than just the difference between a continent and an isolated island. A closer comparison is the one between a desert and a jungle, or between favourable and very unfavourable conditions; for instance, our own Earthly extremophiles are not endangered by our familiar household microbes. Besides, I'm under the impression that this sort of total, dramatic outcompeting mostly tends to happen with larger species.--91.148.159.4 (talk) 15:11, 1 February 2010 (UTC)

The relevant article is Planetary protection. Icek (talk) 06:16, 29 January 2010 (UTC)

From our animals in space article: "In September, 2007, during the European Space Agency's FOTON-M3 mission, tardigrades, also known as water-bears, were able to survive 10 days of exposure to open-space with only their natural protection." 75.41.110.200 (talk) 21:11, 29 January 2010 (UTC)

Questions on quantum mechanics

I am watching a set of lectures on quantum mechanics. So if I start beating down the door in here with questions, try not to beat on me; my education on Newtonian physics was very extremely half-done.

The lecturer is talking about the measuring sedentary electron with a magnetic field placed at either end. According to him, the electron will be "pointing" in a certain direction, namely towards the south. If the magnetic field is then altered at angle θ, then the electron has a likelihood of (1+cos(θ))/2 of emitting a packet of energy (or something like that... I'm inferring the equation... he hasn't gotten there); it is completely random, and it will either emit it, or it won't. If the angle is not changed, the packet will never be emitted; if it is placed at 180 degrees, it will always emit it.

I have two questions on this:

1. what sort of experiment can possibly be done to measure something on such a tiny scale? My brain wants to say this should be unmeasurable, given that we've already established that things on such a small level are, rather, random. I'd think Heisenberg might agree with me on some stage.
2. if the angle is altered by θ, and the photon is not emitted, and then then the magnetic field is readjusted by -θ to the original angle, what is the probability of the packet being emitted? Is it zero or have the probabilities been readjusted along the lines of the new quantum field? And if the packet is emitted, would the readjustment give a probability of 1 for another emission or a new probability based off the realignment?

I hope you don't have to read this question too many times to understand. :) Magog the Ogre (talk) 02:14, 29 January 2010 (UTC)

I was never much of an experimentalist, so I won't try to answer the first question, except to point out that the Stern–Gerlach experiment was an experiment of this type. As for the second question, I'm not sure I understand the details of your experiment, but it definitely constitutes a measurement of the electron spin along the axis of the magnetic field. After the measurement the spin can be treated as either aligned or antialigned with the magnetic field (depending on whether you saw a photon or not) regardless of which direction it pointed before. So when you then rotate the magnetic field by -θ and measure again, the chance of seeing a photon is (1–cos(θ))/2; nothing that happened prior to the previous measurement is relevant. -- BenRG (talk) 05:47, 29 January 2010 (UTC)

I think usually these experiments are done with a lot of particles, not just one. Not only does that make it easier to measure what's going on, but since it's effectively many trials running simultaneously we can find probabilities without having to do the experiment a lot of times in a row. However I think it is possible to measure single photons, like in the Quantum eraser experiment. Rckrone (talk) 07:38, 29 January 2010 (UTC)

Electron spin alignment (and changes to it, and specific energies involved, etc.) is the principle behind Electron paramagnetic resonance. DMacks (talk) 20:56, 29 January 2010 (UTC)

An optical (digital?) microscope

I am interested in buying a relatively small relatively inexpensive optical microscope to view micro-organisms living in/on the human body. Obviously there are very large and very small micro-organisms living in the body, but I'm not looking to look at "all" of them, just a "good number" of interesting little things that I wouldn't be able to see without a good microscope. For example, if I were to take a skin, cheek, saliva, or hair sample, could I realistically expect to be able to classify hundreds, or thousands of microbes with an easily obtainable home microscope? I'm thinking in the few-hundred-dollars range, not the few-thousand-dollars range. Any general information would be helpful, a lot of the brands don't seem to publicize their prices (national security?) and I'm not really sure how powerful/what features I need. I am in Canada, but it seems that I may have to purchase something like this in the US, which I can do if necessary. Thanks in advance! 219.102.221.49 (talk) 02:17, 29 January 2010 (UTC)

Hmm, I have a digital microscope that goes up to 200x it cost about AU$160. I have not looked into it much more then that but i have not seen digital microscopes with much better magnification. However I don't think 200x is enough to see micro-organisms, this is what a bee's face looks like, and this is a fly's wing. I've read that to see cells you need about 1000x-1200x, i have not seen a digital microscope with that power. optical ones i believe can be had for around $300 - $400. i think e-bay seems like a decent enough place to get them, students and all sorts of places off load perfectly good old microscopes all the time. I've been thinking of buying one one day but i need to learn a bit more about them before deciding exactly what to buy. I can't remember the exact name of the USB microscope i got, if you just do a search on e-bay you'll find it. Vespine (talk) 03:35, 29 January 2010 (UTC)

First off, unless you're using oil immersion optical microscopes (digital microscopes are a type of optical microscope) are limited to about 400x magnification. This is enough to see bacteria, although some of the finer detail are not likely to be visible. Secondly, even with high-powered microscopes, you're unlikely to be able to classify thousands of microbes without extra work. Most bacteria look the same rods/spheres/corkscrews. In order to identify bacteria, you usually need to stain them (Gram staining is the best known, but there are hundreds of other types used). That said, I'd try the Carolina Biological Supply Company (most school supply companies sell to hobbyist/home school market as well - check with the local science teachers about where they buy from). They sell a digital camera for ~US$230 that attaches to any regular microscope, or have dedicated digital ones for ~$270 (40x max). If you want a higher magnification than that, you need to go into the $1000+ range. -- 174.21.224.109 (talk) 06:56, 29 January 2010 (UTC)

Since when are dry optical microscopes limited to under 400x? I've owned cheapo $50 student microscopes that went up to 600x! You can get them at Walmart. Presumably this is not the level of quality that the question-asker is hoping for, but how can it be that the serious equipment you're talking about is going to be out-performed by what is essentially an educational toy? APL (talk) 07:04, 29 January 2010 (UTC)

From my experience, most lab grade optical microscopes have a 10x eye piece lens with a variable objective. Commonly this will have 1x, 10x, 40x and 100x objectives. Sometimes the 100x may be excluded. [1] If you use the 100x, you will usually need to use oil immersion if you want to have chance in hell of seeing anything and focusing (the lens be designed for oil immersion). As to why these cheap microscopes have 600x, at a guess 600x is starting to get to the limits where you ideally should be using oil immersion and they don't bother to follow tradition which 99% of lab optical microscopes do. Plus 600x sounds better then 400x. There's obviously no reason why you have to follow this tradition, but 600x is only 1.5x 400x and if it creates issues, plus is unstandard (so for example if you're looking at a picture in a book you may not find 600x) why bother? And most people would probably prefer to have a microscope with a high quality 40x objective lens then one with a shitty 60x one (or whatever). And from a biologists viewpoint I guess, if they do want to go to higher, why not just use the oil immersion? A bit messy and does require a fixed specimen but it's not really as hard or scary as it may seem. The only real big disadvantage is the inability to easily switch between objectives. Nil Einne (talk) 09:16, 29 January 2010 (UTC)

Looking at oil immersion, "State of the art objectives can have a numerical aperture of up to 0.95". This means that at 750nm, the resolving power would be 789nm. At 600x that would be 0.47mm. Rather difficult to see something apart at that level even if you had the resolving power I guess however seems to make sense to contemplate oil immersion. Not that the cheapo microscope is likely to have anything like 0.95 Nil Einne (talk) 09:32, 29 January 2010 (UTC)

P.S. The linked microscope has 900x not 600x. There's some discussions here [2] of the limitations of dry 900x magnification Nil Einne (talk) 09:45, 29 January 2010 (UTC)

To be clear, the maximum NA of 0.95 cited in that article is for air objectives — and those are going to have a very short working distance (space between the surface of the objective lens and the focal plane in the sample) or use a lot of very expensive glass. In practice, most standard-duty air objectives top out at an NA of around 0.75 and a 20x to 40x magnification. (The 10x eyepiece, as noted, is pretty much standard equipment.) For higher resolution and higher magnification, one moves to an immersion objective. Typical water immersion objectives (easier cleanup than oil immersion, though I don't know about their availability for hobbyist instruments) have an NA of around 1.2, while oil immersion objectives can squeeze out a bit more resolution (typically 1.3 to 1.4 NA.) Resolving power is governed by the numerical aperture of the objective lens (typically printed on the lens barrel, at least for good lenses). High magnfication factors are unsatisfying on a low-NA lens — features will be apparently 'larger', but blurry.

Incidentally, if you're planning on spending a lot of time at the microscope, consider purchasing one equipped with (or which can be upgraded to employ) a binocular eyepiece. For extended viewing sessions, the binocular eyepiece is significantly more comfortable than the one-eyed option. TenOfAllTrades(talk) 14:12, 29 January 2010 (UTC)

The idea that a brand of microscope might keep their prices secret for reasons of national security is curious. Is there a conspiracy theory here? Cuddlyable3 (talk) 10:50, 29 January 2010 (UTC)

You would need more than a microscope to identify bacteria at least. I think their classification and hence identification depends on how they stain - for example gramm-positive and gram-negative as far as I recall. I think I remember in the biology lab at school looking at some bacteria through a high powered professional microscope, but the bacteria was still just a tiny little dot. The "microbes" are going to be hidden among a lot of clutter of skin debris. If by microbes you mean bacteria, then you are be disapointed I think. For mites, fleas, and so on, then I expect you would be able to see much more. A drop of pond water should have lots of things in it. 78.149.152.46 (talk) 00:24, 30 January 2010 (UTC)

Yes, keep in mind that "microorganisms" and "cells" all range dramatically in size. For viruses, nothing short of an electron microscope will do. Bacteria can be seen with strong optical microscopes. But there are also many other organisms (such as in pond water) larger than bacteria but still too small to see with the naked eye, that can be easily seen with a low power optical microscope. As for cells, some plant cells are large enough to see without any magnification, and even some animal cells can be seen with little magnification (such as a human ovum). So, the result is that you can see something interesting at just about any magnification level. Therefore, you might do well to consider other factors, like how easy it is to focus in on an image, zoom, light it, etc., than be overly concerned with a high magnification factor. The ability to take pics using the microscope is also a nice feature. StuRat (talk) 20:04, 30 January 2010 (UTC)

magnetic piston thermodynamics.

Supposing a piston in a chamber enclosed in a sleeve of perfectly thermally insulating material was pulled down by a magnet such that the increasing resistance due to air compression was perfectly counteracted by the increasing pull of the magnet. When the air was fully compressed the temperature would have increased. If the insulating sleeve was removed heat could be extracted to do useful work.Bearing in mind that with the sleeve removed, ambient heat could get in the cylinder from outside,so the air would not cool much on the return stroke,would the piston be able to move back up as easily as it had moved down again, to repeat the process like a large scale version of Maxwell's Demon? —Preceding unsigned comment added by Trevor Loughlin (talk • contribs) 06:32, 29 January 2010 (UTC)

Certainly not - what you describe is a perpetual motion machine - and just like every single other efforts to build one of those devices, you're doomed to failure because the laws of thermodynamics says so. We don't need to understand WHY it doesn't work because thermodynamics is a handy shortcut. But I believe what happens is this:

• The piston falls and magnetic potential energy is converted into heat as the air is compressed.
• As the heat from the compressed air is removed, the air gets cooler and therefore denser but the mass of the air is the same - so it's volume must decrease.
• As the volume of the air decreases, so the piston falls a little more.
• Then the machine stops.

I don't see where this "return stroke" comes from. That would require energy because you'd be moving the piston further from the magnet. Where does this energy come from? The answer is that there isn't any spare energy lying around - so it's not going to have a "return stroke". The machine simply transforms the available magnetic potential energy into heat and then stops moving. SteveBaker (talk) 07:05, 29 January 2010 (UTC)

There is research into internal combustion engines that use a magnetic piston as a restoring force. I've seen numerous variants, for example, Linear motor, and ram accelerators. I'm not aware of any practical use of the latter system yet, but the fundamental idea is to extract energy from combustion and make the process cyclic with a restorative electromagnetic force. I think the OP's description fails to account for an energy input, so the process is not really an engine. Nimur (talk) 16:40, 29 January 2010 (UTC)

Yeah - it makes sense. You can often replace a spring with a sufficiently powerful magnet and that's good because magnets don't wear out or break - and where springs wear against the thing they are pushing against and need lubrication, magnets do not. With the advent of super-powerful rare-earth magnets, this becomes a viable possibility. Even more interesting is using an electromagnet so that you can control the force that's applied using a computer. But what the OP is discussing is perpetual motion...and that's an entirely different thing. SteveBaker (talk) 20:00, 29 January 2010 (UTC)

O.K. I admit defeat. But I still maintain that the second law of thermodynamics is unfair and should somehow be abolished.

I agree. Let's get our congressmen to do something about it. Buddy431 (talk) 18:49, 30 January 2010 (UTC)

Yes, the thermodynamic laws have a taste of unfairness to them. That has lead some people to describe them as follows

• 1st law: You can't win
• 2nd law: You can only loose
• 3rd law: You can't quit the game

Dauto (talk) 22:29, 30 January 2010 (UTC)

Most Green Company in the World

What company is the most green at present? Meaning, not only do they produce goods/services that are 'green' but their production/managment/etc is green also? --Reticuli88 (talk) 14:58, 29 January 2010 (UTC)

Editorial content: Such a flat term, is 'green'. It doesn't mean anything to me. Oh, I know what you'll say. The polar icecaps are melting. Fossil fuel is the way of the dinosaurs. Maybe, but so what? My town is not flooded. The cars I see are not running out of gas. The temperatures and weather are as mild as ever. Green schmeen. It's political hype, and as such I do not recognize your question as a valid one. Sorry! Vranak (talk) 15:05, 29 January 2010 (UTC)

I'm not sure if Vranak's reply is entirely a joke or not. But, in any case, I disagree. It is a valid Q. However, "green" is a rather vague term. Different people will have different ways of interpreting it. Let's just look at energy sources, for example. Pretty much all environmentalists will agree that burning fossil fuels is bad, with coal being the worst, and natural gas being the best fossil fuel. But how about burning wood ? Unlike fossil fuels, it is renewable, when responsibly harvested. However, it does release greenhouse gases and air pollution. How about nuclear power, then ? No air pollution there (unless you consider pollution released during construction and mining), but a very small amount of highly radioactive waste is produced. How about hydroelectric power, then ? Well, that involves massive dams which can flood out lots of historic sites and natural habitat, and also can prevent fish from being able to move up and down the river. How about wind and solar power, then ? Those seem fine on a small scale, but, on a large scale, would require a massive amount of land to be converted into what some will consider to be an eyesore. So, which power source is the most green ? It's all a matter of opinion. StuRat (talk) 15:41, 29 January 2010 (UTC)

It's not a joke. I don't joke! Or if I did, it would be funny. Vranak (talk) 17:39, 29 January 2010 (UTC)

I would rather have a sore eye than have to pay to clean up someone else's flood. 99.56.138.51 (talk) 19:02, 29 January 2010 (UTC)

I would say the National Ignition Facility is the most green, since if they succeed in making fusion power they will change the world. The most green company is the one that invents new tech to perform your preferred type of geenness. Ariel. (talk) 19:22, 29 January 2010 (UTC)

Is that a fact? Suppose the yield-rate of new technologies is sufficiently low that they actually consume more fossil-fuel than they offset by inventing new technology? Nimur (talk) 12:53, 30 January 2010 (UTC)

Agreed, ethanol production from corn kernels seems to fall into that category. When the effects of the lower fuel efficiency of ethanol and the increased cost of food are taken into account, ethanol from corn isn't any better than gasoline. Ethanol production from other sources, however, such as waste material, is quite promising. StuRat (talk) 19:41, 30 January 2010 (UTC)

Stinky drawers

My question is about laundry. Here's the scenario:

1) I wash my clothes, using bleach, and they smell good.

2) I put them in a dry drawer.

3) If I take them out in a few weeks, they smell fine. However, if I take them out 6 months later, they stink.

So, what causes this ? Mold and mildew seem unlikely, as the drawer is dry and the musty smell isn't what I associate with those things. Is it poop from dust mites I'm smelling ? I usually end up rewashing the clothes with bleach before I will wear them again. I've heard that putting a fabric softener sheet in the drawer will help, but is that just perfume masking the stink ? Any other suggestions ? StuRat (talk) 15:20, 29 January 2010 (UTC)

Use Space Bags. Dauto (talk) 15:28, 29 January 2010 (UTC)

I have a few issues with them: 1) Do the clothes get wrinkled ? 2) I don't always know ahead of time that clothes won't be used for a long period. If it's near the end of winter, I may wear winter clothes again, if we have some cold days, or may not wear them for 6 months, if it's warm from that point on. 3) Do you know that they stop the musty smell ? If it comes from a natural decomposition of the fibers, then maybe not. StuRat (talk) 15:58, 29 January 2010 (UTC)

Drawer liners are cheap and cover up the musty smell of old clothing. If you have any clothing that is made of biological material (ie: cotton or wool), expect a smell to build up around them if they sit a long time. As for scents, lavender has been chosen over many centuries as the optimal perfume to mask the musty clothes smell. I don't know why. I thought long ago that it would be a cool experiment to see what scents best mask musty smells. I personally replaced the bottom of all my drawers with a plank of cedar. They all come out smelling a bit woodsy, which meets my preference. -- kainaw™ 15:35, 29 January 2010 (UTC)

So, if I do that, people will all say that I smell like I spent the last 6 months in the woods ? :-) StuRat (talk) 16:02, 29 January 2010 (UTC)

My clothes are all cotton or cotton/poly blends. So, what exactly causes the musty smell with natural fibers ? StuRat (talk) 16:02, 29 January 2010 (UTC)

Sounds like some sort of mould to me. --TammyMoet (talk) 16:27, 29 January 2010 (UTC)

Cotton is a cellulose product. Like all cellulose products, it slowly breaks down in the presence of oxygen (and probably other gasses) and it is a delicacy for many small insects (moths, termites, and mites in general). If it breaks down, it produces a "musty" smell. If insects consume it, they produce a "musty" smell. There are *always* mites around. I don't think it is possible to have a home humans can live in without having mites. -- kainaw™ 16:27, 29 January 2010 (UTC)

Will they be present inside the Space Bags ? Would the partial vacuum kill them ? StuRat (talk) 16:34, 29 January 2010 (UTC)

The commercials say that they keep mites out. They don't make any claims about the survivability of mites inside the bags. I just did a google and there is so much marketing crap about dust mites that I don't think it is possible to get a valid answer about anything on the topic on the web. I saw one site that said taking garlic pills will make your skin flakes unpalatable to dust mites and they will leave your home. Complete nonsense. -- kainaw™ 17:46, 29 January 2010 (UTC)

They probably don't smell mustiness in a house full of garlic-eaters, or much or anything else, besides garlic. :-) StuRat (talk) 18:14, 29 January 2010 (UTC)

In my experience if you dry clothes in a drier, rather than in the fresh air and sun outdoors, they start to smell unpleasant after a while despite whatever perfumes are in the washing powder. How do you dry your clothes? 78.149.152.46 (talk) 00:17, 30 January 2010 (UTC)

IME I've used a tumble drier exclusively for 30 years and no unpleasant smells have accrued! It's got more to do with where the clothes are stored and under what conditions. --TammyMoet (talk) 09:11, 30 January 2010 (UTC)

I usually use line drying ie. in the sun. I'm wondering what effect the solar UV would have on any mico-organisms that may be left after washing? I imagine it would kill 'em well and good. Perhaps then reducing the chances of smelly clothes? --220.101.28.25 (talk) 11:53, 30 January 2010 (UTC)

UV doesn't penetrate very far, especially through dark fabric. So, I'd say it might do a nice job at sterilizing a thin, white sheet, but not at sterilizing the shadow side of a thick, dark towel. But, of course, there are also constant sources of contamination outside, like bird poo, insects, and dust blown in the wind, so the clothes may be recontaminated after they've been sterilized. StuRat (talk) 19:33, 30 January 2010 (UTC)

I machine dry my clothes, but do use bleach in the wash, so they are likely to be sterile when done (more likely than clothes dried outside with bird poop on them, I'd wager). The drawer where I place them, however, isn't sterile, and air also goes in and out of the drawer, potentially carrying more little nasties in. StuRat (talk) 19:24, 30 January 2010 (UTC)

Try Mothballs. Our birds are apparently well 'trained' and rarely crap on clothes --220.101.28.25 (talk) 00:26, 31 January 2010 (UTC)

But mothballs make the clothes stink, too. StuRat (talk) 01:55, 31 January 2010 (UTC)

Potpourri perhaps then? --220.101.28.25 (talk) 16:20, 1 February 2010 (UTC)

That would help with the smell, yes, but I'm still grossed out at the idea that my clothes are so full of dust mite poo that they need a stronger scent to mask it. This would likely make me rewash them, anyway. StuRat (talk) 20:00, 1 February 2010 (UTC)

A difficult undertaking

What does a mortician do when the vascular system of the body is no longer intact ? This would seem to be a problem for embalming, as both removing the blood and replacing it with embalming fluid would be difficult without an intact network of arteries and veins. Let's suppose that the head is intact, and an open casket funeral is desired, but the body is heavily damaged, perhaps by a series of shotgun blasts (in this scenario the deceased had apparently fallen out of favor with someone :-) ). StuRat (talk) 15:27, 29 January 2010 (UTC)

In an open coffin, the corpse is clothed. These clothes would not be the ones the deceased had died in, so the bullet holes would not be visible. An ex-student of mine, who was studying embalming (I was helping him with his English, before you ask) told me that he'd had to work on someone whom he couldn't embalm in the normal way for some reason (IIRC it was a car crash victim), and had had to embalm by immersion in formalin. Of course, this might not be the exact answer you're looking for! --TammyMoet (talk) 16:25, 29 January 2010 (UTC)

I thought about that method, but wouldn't such a body smell strongly of embalming fluid and thus be unsuitable for an open coffin ? StuRat (talk) 16:58, 29 January 2010 (UTC)

You could not embalm the corpse? Embalming is still rare in Britain and Ireland, and is not essential. Fribbler (talk) 17:28, 29 January 2010 (UTC)

Really ? I think either rapid embalming or cremation is required in the US, for public health reasons. Aren't Brits and the Irish concerned about spreading disease ? StuRat (talk) 18:09, 29 January 2010 (UTC)

Emblaming is not required by law in the US or Canada in most cases. Check any funeral director's web site in your jurisdiction for the laws in your area. Embalming is generally used if the funeral rites are to involve an open casket, as noted above. Notwithstanding that there are few legal requirements, most US and Canadiab bodies are embalmed. (I'll put some links in later today if no one else has by then.) Bielle (talk) 18:48, 29 January 2010 (UTC)

As promised, here are some links and more information:

This site looks at Canadian law and embalming and summarizes thus: “Does a dead body have to be embalmed, according to law? No. Most provinces, however, require embalming when death was caused by a reportable contagious disease or when remains are to be transported from one province to another by common carrier or if final disposition is not to be made within a prescribed number of hours”.

For the U.S. perspective, see here. The rules are similar: “Embalming is not routinely required by law, but may be necessary if death is due to certain diseases; if final disposition is not made within a prescribed period of time; if refrigeration or immediate burial is not available; or if a body is to be transported between states or internationally in a common carrier.

’Some states require embalming for transportation within the state, beyond the place where death occurred. Funeral directors may require embalming if the funeral ceremony selected by a family includes viewing, and they are generally required to ask permission of the deceased's next-of-kin verbally or in writing before embalming.”

There are religions where embalming is forbidden. I recall among them Orthodox Judaism, Islam and Bahai, though all would be subject to local law, with some exceptions. Bielle (talk) 01:48, 30 January 2010 (UTC)

The health risks from dead bodies are minimal in most cases. You can only catch disease from them if they had that disease when they died and, if they are kept on a mortuary slab and then put in a coffin, and you only touch them when wearing gloves (all of which is how dead bodies would normally be dealt with), then only air-borne infectious agents are a risk and that risk is no greater than the risk from a living person with that disease. Most contagions can't survive in a dead body for long, anyway. This recent BBC News article about the health risk from all the dead bodies in Haiti describes the matter in more detail (although the risk is obviously greater from bodies lying on the ground where they may in contact with water that people are drinking than it is from bodies in a coffin - the article still concludes that the risk is very small). --Tango (talk) 11:03, 30 January 2010 (UTC)

Thanks for all the info, everyone. So then, the only alternative way to embalm a body is by immersion in embalming fluid ? StuRat (talk) 19:28, 30 January 2010 (UTC)

I'm not sure the 'embalming fluid' would be able to adequately penetrate a body from simple immersion. --Neptunerover (talk) 23:55, 30 January 2010 (UTC)

Perhaps not normally, but the scenario I proposed has the body full of holes. StuRat (talk) 01:52, 31 January 2010 (UTC)

I see. That could make a difference, yes. --Neptunerover (talk) 08:18, 31 January 2010 (UTC)

Perhaps then a simple pickling in an alum and salt solution? --Neptunerover (talk) 08:21, 31 January 2010 (UTC)

Or in rum. Every man expects that England ... hic. BrainyBabe (talk) 10:04, 31 January 2010 (UTC)

I'm having me an All-U-Can-Eat Dolphin Meat-a-thon Dinner in Japan

I'll have the McDolphin-Mac please! Lets say I ate large portions of dolphin meat with "Mercury_(element)", aka poison, in it--which is a Diamagnetic, the Bioaccumulation of this magnetic element in the body, I'm sure can cause Neurosis. Afterwards I see my neuro doc friend and have fun with the MRI, EEG, and/or EKG tests. My question is this, if I have magnetic poisons in my blood stream, wouldn't the MRI, EEG, EKG tests, the very Magnets of those tests, pull all of those poisons/toxins to that particular part of the body--closest to the magnets? What kind of neuro-distruptions could this cause? --i am the kwisatz haderach (talk) 17:11, 29 January 2010 (UTC)

Diamagnetism causes a repulsive effect in the presence of a magnet. So even if the magnets had an effect, it wouldn't pull the Mercury to them.--160.36.39.222 (talk) 17:34, 29 January 2010 (UTC)

I am certain that I saw this on a TV show, though it may have been some other metal that had suffused the patient's body in this fictional thread. Doctors turned on the MRI, and zap! All the magnetic particles zapped right out of the patient's body, and he was a dead bloody mess. Comet Tuttle (talk) 17:43, 29 January 2010 (UTC)

If you had large enough magnetic particles in your body this might actually be possible. I can imagine having such large particles in the digestive tract, perhaps, but don't see how they would get anywhere else without you knowing it. Very small particles (like the iron in hemoglobin in the red blood cells) wouldn't be ripped from the body because the magnetic force on them is small compared to the other more local forces which hold the molecule together and in place. There might be an in-between region, where the particles do shoot out of the body, but the holes they leave are so small as to not cause any serious problems. After all, many substances can diffuse through intestinal walls, capillary walls, skin, etc., without causing any problem, as this is part of normal life. StuRat (talk) 18:06, 29 January 2010 (UTC)

The small enough particles, those ones moving around in your Brain region, I think that could disrupt normal synapses yes? --i am the kwisatz haderach (talk) 18:12, 29 January 2010 (UTC)

I would expect that any particles large enough to do that would be too large to diffuse through body membranes and get there in the first place, unless we imagine that many small magnetic particles would conglomerate together to form larger ones. StuRat (talk) 18:36, 29 January 2010 (UTC)

If this were true MRI machines would be deathtraps that killed anyone who walked past them, let alone got inside them. Clearly this is not the case, MRI complications almost always involve accidents with large chunks of metal (oxygen bottles for example) or bits of metal that have been implanted. Not microscopic particles that are floating through the body. APL (talk) 18:52, 29 January 2010 (UTC)

BTW, if you are really eating dolphin, you have more to worry about then mercury Dolphin drive hunting#Human health concerns Nil Einne (talk) 20:08, 29 January 2010 (UTC)

Metal-workers may have small metal particles embedded in their skin, eye, etc, either too small to notice at the time or remnants from incompletely removed pieces. Along the same lines, bullet-fragments or metal implants could be dislodged. DMacks (talk) 20:50, 29 January 2010 (UTC)

The Mythbusters did an actual test of this - the claim was that the iron in old-style tattoos could be ripped out of your skin. That idea came up in an episode of "House" too. House claimed it would be horrifically painful - Mythbusters claimed that there would be no effect. SteveBaker (talk) 02:26, 30 January 2010 (UTC)

P.S. For clarification, when I said 'worry about' I meant for reasons other then alleged negative effects when entering MRI machines Nil Einne (talk) 08:06, 30 January 2010 (UTC)

How much mercury is in a dolphin? Just for an order of magnitude idea, this article seems to imply it is around the range of 1.32 mg/kg. Let's say you ate, I don't know, three pounds of dolphin meat—which is kind of an extreme amount anyway. That gives you a mercury intake of about 4 mg. That's not very much mercury, from a magnetic standpoint, diffused in the bloodstream. Would an MRI be able to pick that up? I'm pretty dubious. You have much, much more iron in your blood than that—and this site gives a pretty good explanation why there aren't any significant magnetic effects on that. So, I'm no scientist, but it seems soooo unlikely to me that eating dolphins is going to have any MRI-based effects. (Much less EKG or EEG which don't use as big magnets, I don't believe.) The amount of mercury is just blindingly small from a physical standpoint (even if it is not from a biological standpoint). --Mr.98 (talk) 03:38, 30 January 2010 (UTC)

Swiss Climate

Haa Valley, Bhutan.

Where else in the world can you find a climate and topography similar to Switzerland? In particular towns running along river valleys surrounded on BOTH sides with huge mountains? But with lots of greenery during the spring so nowhere at extreme latitudes or elevations. Ideally not in Europe either (so Austria, southern Germany) would be uninteresting answers. TheFutureAwaits (talk) 17:27, 29 January 2010 (UTC)

Colorado ? StuRat (talk) 17:57, 29 January 2010 (UTC)

Thimphu, Bhutan comes to mind. --※Cōdell 19:35, 29 January 2010 (UTC)

New Zealand? Maybe?? (Never been there) --220.101.28.25 (talk) 20:38, 29 January 2010 (UTC)

Norway and British Columbia and the Scottish Highlands. Inland Japan as well. Vranak (talk) 21:29, 29 January 2010 (UTC)

Chile's lake district is often likened to Switzerland.--Eriastrum (talk) 20:53, 30 January 2010 (UTC)

Not quite sure what you mean. Are the towns essential to your vision or not? Plenty of places high enough to give you altitude sickness burst with verdancy in the spring. Kyrgyzstan likes to bill itself as the Switzerland of Central Asia -- that would be for the similarities in practices of Transhumance, not for the banking system. Some people like Kamchatka. Parts of Costa Rica have mountains with a climate similar to Switzerland's in the summer. Japan is highly mountainous, with most of the population crammed on the sea plains. Nepal and Tibet... one could go on and on. BrainyBabe (talk) 10:28, 31 January 2010 (UTC)

how does carbon dioxide poisoning induce lesioning and fluid discharge, etc.

Was reading some article where a patient described nasty sores and various discharges on his body after recovering from CO2 poisoning.... did he vomit while unconscious? Flail around? John Riemann Soong (talk) 17:28, 29 January 2010 (UTC)

Do you mean carbon monoxide poisoning? Dauto (talk) 17:34, 29 January 2010 (UTC)

Well I really mean carbon dioxide poisoning....e.g. from a limnic eruption. John Riemann Soong (talk) 17:47, 29 January 2010 (UTC)

Carbon dioxide isn't poisonous. It can suffocate though. Dauto (talk) 18:43, 29 January 2010 (UTC)

Carbon Dioxide disagrees with you 157.127.124.15 (talk) 19:18, 29 January 2010 (UTC)

That section needs some clarification; it says that CO2 at 8% will cause loss of consciousness, but it doesn't really say what the other 92% is. If the other 92% is ordinary air, that would still leave about 18% O2, which I think is still plenty to sustain consciousness, but I don't know just where the cutoff is.

Still, I think it's completely clear that if you try to breathe 80% CO2, 20% O2, you'll be fairly dead fairly quickly (but painfully), in spite of the fact that you're still being supplied with plenty of oxygen. Anyone who doubts it, just take a whiff right above the punch bowl that's bubbling from dry ice. If it feels like that in your nostrils, just imagine trying to fill your lungs with it. --Trovatore (talk) 23:16, 29 January 2010 (UTC)

Carbon dioxide is most certainly toxic above a certain threshold, regardless of the amount of oxygen in the air. CO₂, in the forms of bicarbonate and carbonic acid, acts to regulate the pH of the blood. An excess, however, can imbalance this system in favor of carbonic acid, lowering the blood pH and leading to a condition known as acidosis. – ClockworkSoul 05:39, 30 January 2010 (UTC)

An excess of carbon dioxide (even when there is a normal partial pressure of oxygen) is definitely toxic. As ClockworkSoul notes, elevated carbon dioxide levels can lead to acidosis and interfere with the oxygen-carrying capacity of hemoglobin. (See also hypercapnia and Bohr effect, along with Carbon dioxide#Toxicity.) At standard pressure, 10% carbon dioxide is quite lethal, even if the breathing mixture still contains 20% oxygen. TenOfAllTrades(talk) 05:53, 30 January 2010 (UTC)

From the article "Limnic eruption": "Many victims were found with blisters on their skin. This is believed to have been caused by pressure ulcers, which likely formed from the low levels of oxygen present in the blood of those asphyxiated by the carbon dioxide." Reference Axl ¤ [Talk] 19:28, 29 January 2010 (UTC)

NSA, FBI, CIA Automatic KEYWORD Internet Search for BODY of Electronic-Messages

I'm not sure if our Governments are really reading our e-mails. But if I wanted to send a Private Love Poem to my girl, and hypothetically I had a demented sense of humor, rhyming about 09.11, The World Trade Center falling, Al-Qaeda, things of this nature. Or even if I was really socially acceptable wordly heartfelt, and wanted to send a private Arabic poem, speaking of Muhammad’s Passion equaling the passion of my own heart, Peace be upon him. Could I just save my poem on a NOTEPAD file, and send as an attachment, maybe just put a ":)" in the body of the email, would this curb the ever watchful eyes of possible Government Security Protocol programs? --i am the kwisatz haderach (talk) 17:33, 29 January 2010 (UTC)

You don't seem to think very much of the top minds of the world's premiere surveillance organizations. Projects like ECHELON and Carnivore and its successors surely scan attachments, too. (IP traffic is scanned at a lower level, so it's not just e-mail, so really everything going across the wire would be scanned.) Encryption of your messages with a sufficiently long key is the only method that is presumed to save you from this eavesdropping. By the way, on your first point, when Usenet was the chat board and Reference Desk of the Internet, there used to be a script, allegedly popular (though I don't remember actually seeing it invoked), which would append an inflammatory randomized tag to every single post you wrote. Each post would end with a .sig including stuff like "Bring the shotguns. I will meet you at City Hall at noon." The juvenile point was to try to waste time of the surveillors, which at the time were presumed to be human. Comet Tuttle (talk) 17:49, 29 January 2010 (UTC)

It wasn't just "allegedly" - it definitely exists. It was a set of scripts that were shipped with the EMACS text editor called "Spook"[3]. It probably still exists. You hit ALT-X and then typed 'spook' and it would add all of these assumed-to-be-dangerous keywords into your email and someone on the other end who was reading the email using the same system ("UnSpook" IIRC) would not see them show up on the screen. It was thought that the spies would be so bombarded with false positives that they would be unable to function. Of course the world was a different place back then - personal privacy was a huge deal and terrorism wasn't. Doing a hack like that these days could get you into all sorts of deep doo-doo. SteveBaker (talk) 02:11, 30 January 2010 (UTC)

Yep - it still works. I just fired up emacs on my OpenSuse computer - and also on Windows 7 on my work computer. Typing Alt-X spook produced:

"Mantis cypherpunk Venezuela STARLAN Peking Skipjack world domination Vickie Weaver bce Perl-RSA Montenegro Attorney General Compsec Ron Brown smuggle"

...and under Win7...

"Ermes threat propaganda ANDVT pink noise Uzbekistan militia Montenegro rs9512c insurgency Crowell Delta Force Ft. Bragg jihad CIA"

...er SORRY nice Mr Echelon person sir - that was just a test! :-) SteveBaker (talk) 02:23, 30 January 2010 (UTC)

Awesome. Thanks. Comet Tuttle (talk) 19:13, 1 February 2010 (UTC)

(ec)

I'd say that they probably get billions of such e-mails flagged as being "of interest" due to the keywords. Most of those probably just languish in a huge database, as there is nobody to read them. However, if one of the people who is sent the e-mail happens to be on the terrorist watch list, then they might have enough interest to actually read it. StuRat (talk) 17:53, 29 January 2010 (UTC)

So a real bonifide terrorist, could just mispell words and or create Mafia slang, like calling things of terror Jellybeans, and if that became common criminal talk. In that Alternate Future, I titled my poetry "Jellybean", then I might bump myself up onto the watchlist. --i am the kwisatz haderach (talk) 18:08, 29 January 2010 (UTC)

Or just encrypt it. Or use code-words, sure. --Mr.98 (talk) 18:53, 29 January 2010 (UTC)

I think it's reasonably safe to assume that the CIA, NSA, MI6, whoever, are not the bungling idiots that you're imagining. But it's certainly true that THEY will never be able to effectively monitor all email because of problems with encryption, new channels of communication,cyphers, steganography, codes, etc. But don't worry about it. This is why those agencies employ spies. Spies are a tried and true intelligence gathering method that has worked reasonably well for thousands of years. Things like wiretapping and echelon are modern gimmicks by comparison. APL (talk) 18:59, 29 January 2010 (UTC)

You'd hope, right? But there is a lot of appeal to the "get all the info and 'connect the dots'" idea, even if its utility from a security point of view is low. And it is pretty well-documented that they make a lot of mistakes in this way (e.g. Ted Kennedy on the "no fly list"). --Mr.98 (talk) 19:07, 29 January 2010 (UTC)

Oh, I'm not saying that those things are worthless, or that our intelligence agents are saints and geniuses, I'm just saying that we don't need to panic just because the Internet can't be covertly monitored 24/7 with 100% accuracy. The spy agencies didn't throw away their spies when they got computers. (One assumes.) APL (talk) 19:17, 29 January 2010 (UTC)

On the question of using smileys... this came to mind. "Just because you put 'ha ha' doesn't make it funny!" :-) --Mr.98 (talk) 19:07, 29 January 2010 (UTC)

Mua'dib, The more you try to hide your message, perhaps the more interest 'they' will show in it. So send it in plaintext and they may ignore it totally. (Mr.98, you have to add a wink ;-) then they know you're not serious!) --220.101.28.25 (talk) 19:45, 29 January 2010 (UTC)

It's true that if you start sending out tons of encrypted files, that will probably attract attention of a scanner. Or maybe not. I don't know how common encryption is for e-mail, though I imagine it is pretty uncommon. Any e-mail based scheme is going to have some difficulties for passing secret messages that do not have the possibility of attracting the attention to whomever is sending the message (which is more of a threat than them breaking your encryption). --Mr.98 (talk) 20:15, 29 January 2010 (UTC)

OK, I came up with a better scheme. Basically you write a program that makes all of your secret messages look like spam. Then you send them from Hotmail accounts. Hidden! --Mr.98 (talk) 20:31, 29 January 2010 (UTC)

Um do you seriously think sending it as a plain ASCII (or whatever) txt attachment is going to in any way hinder surveillance? Nil Einne (talk) 20:05, 29 January 2010 (UTC)

It's more likely that they'll find one or two known terrorist sympathisers - find all of the people who send or receive email from them - then find all of them who talk to other people on that list. At this early stage, it doesn't matter what the messages say - the most interesting thing is the patterns of people who communicate with each other as a group. You only have to find one fairly low level person in that group and you can infer all of the rest. Once you have narrowed down your list of suspects, you can look back at all of the trillions of messages that ECHELON has been archiving and look for peaks of message traffic between these people around significant terrorist events. Without decrypting a single byte, they've pulled a net around perhaps just a handful of bad guys and maybe ten times more innocent people. By the time they have it reduced to that low level, they can attack the messages with code-breaking technology. Using alternative words for things is just another pretty poor encryption method and their algorithms can crack that. If there were messages around 9/11 between suspected badguys saying "Fly the two jellybeans into the two big enchiladas" - then code cracking methods can extract the real data just as easily as if the bad guys had replaced every 'A' with a 'B' every 'B' with a 'C' and so on. It's just a matter of having enough messages to crunch on. SteveBaker (talk) 02:11, 30 January 2010 (UTC)

Agree. See this article Traffic analysis --220.101.28.25 (talk) 12:09, 30 January 2010 (UTC)

Real bad guys, whether terrorist or merely criminal, would use commonplace substitutes for words indicating criminal intent. "Tell our friends, that we have decided to have the jagged edges smoothed down, and that we will pay $10" might mean "We agree to pay $10,000 to have two witnesses exterminated." Sadly, if I am the church's Property Chairman, and I email the rest of the Property Committee "I recommend we pay Don $12,500 to remove the loose plaster, replaster and paint the belfry walls. Our new traps eliminated two mice from the kitchen" it is likely to draw undue attention from the superspooks. Edison (talk) 03:55, 30 January 2010 (UTC)

The security issue is not, so much, the content, as it is the networks formed. This is why I think spamming would be a bit more ideal—a group of people send out large nets of information to large numbers of people, and only the "informed" person will know how to distinguish it as actually being secret ham rather than spam. It would make a much more complicated trail for anyone to try and "connect", especially if the scheme for distribution was based around certain random hotmail addresses (e.g., each message would send and receive only once... you'd have a series of addresses generated by a timecode or something). Spam is one of the few means of e-mail communication where we expect the senders and recipients to be kind of random spreads. It's kind of akin to writing on a bathroom wall in a crowded pub. --Mr.98 (talk) 15:51, 30 January 2010 (UTC)

hanging

The Hanged Man (tarot card)

According to the apocryphal Acts of Peter the saint was crucified hanging head down. Cuddlyable3 (talk) 18:47, 30 January 2010 (UTC)

if someone is hung upside down by their feet how long till they passout- note i said passout not die —Preceding unsigned comment added by 67.246.254.35 (talk) 18:03, 29 January 2010 (UTC)

I don't believe that they necessarily would; the human circulatory system (in healthy individuals) is capable of maintaining proper blood flow, even in odd bodily positions. --Ludwigs2 18:20, 29 January 2010 (UTC)

It depends, eventually everyone will go into shock if you hang them upside down long enough; the healthiest from dehydration. 99.56.138.51 (talk) 19:04, 29 January 2010 (UTC)

So why did that guy in Nutty Putty Cave die? Ariel. (talk) 19:17, 29 January 2010 (UTC)

"Utah County Sheriff Jim Tracy said Jones' exact cause of death will probably never be known but contributing factors likely included his inverted position for a prolonged period of time and the cave's cold temperatures."[4] Clarityfiend (talk) 04:23, 30 January 2010 (UTC)

Here is a news story relating to David Blaine#Dive of Death I found. He probably used tricks, but the quotes from doctors might be helpful. Ariel. (talk) 21:01, 29 January 2010 (UTC)

David Blaine is a magician. Magic Finally Revealed showed how it is done. 67.243.7.245 (talk) 05:11, 30 January 2010 (UTC)

I can think of several ways that an inverted position could cause death:

1) Stroke/anneurism/cerebral hemorrhage. The increased blood pressure in the head may cause any weak blood vessels there to burst.

2) Insufficient blood flow. Blood may pool in the head, and not circulate properly, ultimately leading to death from lack of oxygen to the brain.

3) Vomiting and aspiration of vomit could damage the lungs and/or block the airway, again preventing enough oxygen from being absorbed.

4) The way in which the body is suspended could itself cause a problem. Ropes around the feet, for example, could cut off circulation there, leading to gangrene and blood poisoning.

Of course, you asked about passing out, which I would expect to happen in each of these cases, some time before death. Stroke could happen immediately, while blood poisoning would likely take many days to develop.StuRat (talk) 19:03, 30 January 2010 (UTC)

one also has to consider complications. for instance, inverted hanging combined with significant exposure to cold or heat could put an undue strain on the circulatory system. --Ludwigs2 19:24, 30 January 2010 (UTC)

What's the term for the religious practice in India of being buried upside down in the ground for several days? ~AH1^(TCU) 03:15, 1 February 2010 (UTC)

Sun's position throughout the year

The sun is at the lowest solar declination on December 21 at -23.44°. After that date, the solar declination increases throughout the winter and spring. After June 21 or 22 depending on the year, which is the sun's highest declination at +23.44°, the solar declination decreases throughout the summer and autumn until December 21 or 22 depending on the year. Currently on January 29, 2010 the solar declination is -17.95°, which is the opposite of November 13, 2009. As the solar declination increases, then the sun's altitude in the sky increases or get higher in the sky in the northern hemisphere, whereas decreases in the southern hemisphere. The changing sun's altitude affects the amount of sunlight it gets into my house. All my kitchen and family windows face south. So as the solar declination increases, the amount of sunlight it gets into my kitchen and family room decreases, and vice versa. My house also has my arch windows in the kitchen, one facing at the azimuth of -165° and the other at -195°. For example, the sun shining through the arch window (or "archshine") on my basement door, as the solar declination increases the arch distance from the floor decreases or literally "the arch is going down". Whereas as the solar declination decreases, the arch distance from the floor increases or literally "the arch is going up".

There are informal terms of seasons when the specific solar declination changes:

• Winter: Norther in the Southern Hemisphere
• Spring: Norther in the Northern Hemisphere
• Summer: Souther in the Northern Hemisphere
• Autumn: Souther in the Southern Hemisphere

--BlueEarth (talk | contribs) 18:58, 29 January 2010 (UTC)

Having not seen your house, I would still tend to say correct; no question. 99.56.138.51 (talk) 19:07, 29 January 2010 (UTC)

BlueEarth has made a small error, and has also given us insufficient information.

He states that "Currently on January 29, 2010 the solar declination is -17.95°, which is the opposite of November 13, 2009." No. On those two dates the declination was the same, not opposite. What was opposite was the direction the sun was moving. In November it was moving southward, in January, northward.

I have no idea where your house is located. If you are north of the Tropic of Cancer, the noon sun is always to your south. B00P (talk) 01:27, 30 January 2010 (UTC)

... and this only works with seasons as defined in the USA. Elsewhere, they are often differently defined. Dbfirs 07:56, 30 January 2010 (UTC)

Rally? I never heard of any alternate definitions for the seasons. Could you give us an example? Dauto (talk) 15:06, 30 January 2010 (UTC)

Many places have a wet, or monsoon season, and a dry season, if that's what was meant. StuRat (talk) 20:32, 30 January 2010 (UTC)

No, I meant Spring (season), Summer, Autumn & Winter which are not, elsewhere, defined as they are in the USA. Dbfirs 17:56, 31 January 2010 (UTC)

Sorry, I should said 'same as November 13, 2009' instead of 'opposite of November 13, 2009. My house is located in Tinley Park, Illinois near Chicago. BlueEarth (talk | contribs) 23:58, 30 January 2010 (UTC)

Good. And now that we've got that cleared up, what is your question? B00P (talk) 17:04, 31 January 2010 (UTC)

Pluto's atmosphere

Pluto is made of frozen gases. When sun heats up what makes people think it will get outgassing that quickly. The frozen gas do become an atmosphere when anti-greenhouse effect goes down. When molecule moves faster then frozen nitrogen gas wilol sublime into envelopes of atmosphere and it will end up ilike Titan (moon) now.--209.129.85.4 (talk) 20:52, 29 January 2010 (UTC)

The gas can escape quickly because the gravity of Pluto is low. Take a look at atmospheric escape - the type of gas, temperature, and gravity all affect the rate which gas escapes into outer space. I can't understand your question about "anti-greenhouse effect" - can you elaborate? Nimur (talk) 21:19, 29 January 2010 (UTC)

When sun heats up Mars can heat up to build an atmosphere though Mars have no magnetosp. This is a google page, some users may have access to it but it is properly cite.--209.129.85.4 (talk) 21:45, 29 January 2010 (UTC)

Also consider that Pluto has a huge moon, Charon (moon), and two smaller moons. This may increase outgassing in several ways:

1) Charon presumably has less gravity, so outgassing from it is more likely. It may not be possible to determine, from Earth, whether outgassing is from Pluto or Charon.

2) Tidal effects between Charon and Pluto may cause both to heat up somewhat. That is, unless they are dual tidally locked. Our article says that they are, but I would guess that's just an assumption due to their relative masses and distance. If one was recently perturbed by a major impact, this may not be the case.

3) The apparent gravity on the side of Pluto closest to Charon (and vice-versa) may be significantly less, allowing for more outgassing. StuRat (talk) 18:42, 30 January 2010 (UTC)

Correction to the original statement: Pluto is not made of frozen gases. Comet Tuttle (talk) 06:09, 1 February 2010 (UTC)

visibility on the moon

If you were an Apollo astronaut standing on the moon, what is the smallest object you could see on earth (unaided, assuming daylight on earth, no clouds in the way)? Would Australia be visible? Madagascar? Great Britain? Cuba? Malta? Smaller? Googlemeister (talk) 22:02, 29 January 2010 (UTC)

The smallest resolvable element would be about 150 km in size. I'll leave as an exercise for the reader to figure out what a good example is. Dragons flight (talk) 23:03, 29 January 2010 (UTC)

Specifically, at Naked eye#Basic accuracies the limit of resolution of the eye is given as about 1-2' (1 to 2 minutes of arc). At the distance of the moon 1' corresponds to 68 miles or 110 km. The low contrast between green or brown land and blue sea would make it harder to distinguish fine details, particularly when the brilliant white clouds in other places draw your attention. It's think in most places the best you could do would probably be 2' or maybe even larger. Seeing Malta would probably be marginal; Madagascar or Great Britain should be easy under good conditions. --Anonymous, 01:18 UTC, January 30, 2010.

I hope Australia would be visible, but this (not from the Moon unfortunately) suggests there are times when it may not be very visible, but is still there. Oz is in the right picture, lower right edge. I would wave but you can only see Perth in this piccy. Boo Hoo, sniff --220.101.28.25 (talk) 23:39, 29 January 2010 (UTC)

Yes - but that photo is misleading. From the perspective of someone standing on the moon, the earth would maybe be no wider than your thumb at arm's length. So unless you are reading this on your iPhone, you might have to stand a fair way back from your computer screen to get the right idea of what you'd be able to see. SteveBaker (talk) 01:49, 30 January 2010 (UTC)

At the risk of stating the blindingly obvious, the Earth as viewed from the moon should appear 3.7 times larger across than the moon does when viewed from the Earth. Dragons flight (talk) 02:33, 30 January 2010 (UTC)

How about this piccy then? Better? --220.101.28.25 (talk) 03:07, 30 January 2010 (UTC)

What's not obvious, so should have been stated, is that "your thumb at arm's length" is the standard description of the angular diameter of the moon from Earth. That is what makes your comment relevant! Steve got a little confused, it seems. --Tango (talk) 13:21, 30 January 2010 (UTC)

No, "your thumb's width at arm's length" is the standard description of one degree. The Moon subtends half a degree. --99.237.234.104 (talk) 04:49, 31 January 2010 (UTC)

It's worth mentioning that this is also the smallest object you can see on the moon from the comfort of your own back yard...assuming night on earth and no clouds in the way. That would allow you to just about spot Babbage. Incidentally - the astronauts all had close to perfect vision - it was a significant qualifying factor for the moon missions. So from the earlier answers, I think 70km would be a good number. Orders of magnitude (length) (I just love all of those "Orders of magnitude" articles...they are great for answering these kinds of question!) says that you'd be able to see the Bering Strait - but not the Strait of Gibraltar. You would be able to spot some of the worlds largest cities - NewYork with all of it's suburbs, for example should be just about visible. SteveBaker (talk) 01:46, 30 January 2010 (UTC)

I suspect the contrast ratio of urban development would be too low to differentiate it from undeveloped land. This NASA discussion about visibility from low earth orbit brings up some interesting points. Nimur (talk) 13:04, 30 January 2010 (UTC)

It would be much easier at night - you could almost certainly see a bright spot in the light pollution that corresponds with New York. --Tango (talk) 13:21, 30 January 2010 (UTC)

So NYC is both a literal bright spot and a metaphorical dark spot, when it comes to light pollution. StuRat (talk) 18:34, 30 January 2010 (UTC)

Yes, light pollution is poetically problematic! --Tango (talk) 20:45, 30 January 2010 (UTC)

How much heat loss through a door slightly open?

My home thermostat is set to 72 degrees and it's 26 degrees outside, if my wife goes outside and leaves an otherwise well insulated door about a crack (about 1/4 inch) for 5 minutes how can I get a rough approximation of the heat lost, or more specifically the cost of replacing that lost heat. My house uses natural gas for heat, not sure of current rate. Don't want to argue with the mrs if it is only few pennies! 205.157.110.11 (talk) 22:30, 29 January 2010 (UTC)

I just stopped at "72 degrees" and melted into a large puddle. :-) Bielle (talk) 22:34, 29 January 2010 (UTC)

It is almost certainly less than a penny per five minute episode. Dragons flight (talk) 23:20, 29 January 2010 (UTC)

Temperatures in Fahrenheit I presume? Though it probably makes no difference to the question. 220.101.28.25 (talk) 23:45, 29 January 2010 (UTC)

Since you said 72° and 1/4 inch, just for fun I'll do this in non-metric units. Say the door is 7 feet high; then the opening is 21 square inches. Say that cold air comes in through the crack at 15 mph (a pretty high estimate in most weather conditions) for 5 minutes. Then the total volume of air is 21 × 15 × 5 square inch mile minutes per hour, which is about 960 cubic feet according to units (software). The volumetric heat capacity of air at the freezing point is about 0.0013 J/cm³·K, which is about 0.019 BTU/ft³·°F. So assuming that this remains reasonably constant through the temperature range, to raise the air from 26° to 72° you need 960×(72-26)×0.019 = 840 BTU of heat.

Googling on "cost per BTU", the first web page I hit says that burning one cubic foot of gas yields about 1,000 BTU. On my last gas bill I paid about $70 Canadian, plus 5% tax, for 212 m³ of gas, which is about 7,500 cubic feet, so one extra cubic foot would cost me almost exactly 1¢.

--Anonymous, 23:52 UTC, January 29, 2010.

Wow awesome responses, thank you all —Preceding unsigned comment added by 205.157.110.11 (talk) 00:59, 30 January 2010 (UTC)

Anonymous' math seems impeccable...and if the door remains just 1/4" ajar, it's obviously no big deal. Of course if the door is open 1/2", that doubles the cost, one inch and it doubles again. My main concern is that if the door is not latched then if the wind catches it and blows it all the way open then the gap is now about 30" wide - so the loss would be $1.20 which would certainly get noticable if it happens several times a week. However, at that scale, there comes a point where all of the warm air in the room disappears outside and the subsequent cost is limited by the amount of time the heating remains on with the door wide open plus the cost of raising the heat back up to 72 degrees after the door is eventually shut again. In that case, the size of the room becomes a limiting factor. So I think it's worth keeping it shut, just on general principles...but it's not worth creating a major family ruckus about. SteveBaker (talk) 01:22, 30 January 2010 (UTC)

I would object loudly to someone creating a 21 square inch (135 sq cm) opening to the outside when the outside temperature was 26 F (-3 C). The proper utterance would be: "Wuz you raised in a Barn? Shet the damn door! Edison (talk) 03:46, 30 January 2010 (UTC)

... plus the psychological effects of the draught created by an open door are percieved as much more uncomfortable than would be expected from the actual reduction in temperature. Dbfirs 07:46, 30 January 2010 (UTC)

Not just psychological; your body physically loses heat more quickly in moving air, by evaporation and convection - the Windchill effect. Alansplodge (talk) 09:44, 30 January 2010 (UTC)

When the hole doubles in area, does it really lose only double the heat? Is it really linear? 95.112.174.46 (talk) 16:55, 30 January 2010 (UTC)

Yea, I question that, too. I believe that heat loss due to radiation and conduction would indeed be close to linear. However, convection losses and those due to wind would not, and those would be a major component of the total heat loss.

I'm also curious as to why the door is left open a quarter inch. My guess is that the door automatically locks when latched. If so, one suggestion is to add a storm door that automatically closes, but doesn't automatically lock. StuRat (talk) 18:26, 30 January 2010 (UTC)