Wikipedia:Reference desk/Archives/Science/2010 August 26

= August 26 =

Hitler DNA
It's that time of the year again, when the papers are desperate to fill up space and will publish just about anything.

A week ago, Belgium's Knack.be published "news" of a "study" that "determined" that Adolf Hitler's DNA contained a haplogroup found more often in North African (Somali, Berber), Southern European (Greek, Sicilian), and Jewish populations than in the general European population. The story languished for a week, was picked up by the UK's tabloid Daily Mail, and then exploded across the Internet, all the while morphing to become even more sensationalistic and titillating. Supposedly respectable newsmagazine TIME, in a regular column titled "It's Science" authored by Megan Gibson, headlined its "report" New Research Shows That Hitler Had Jewish Roots.

Predictably, people have started streaming in trying to insert this "breaking news" into Wikipedia. Initially they came from the crazy/evil range of the spectrum, now they're mostly ignorant doofuses taking everything they read at face value. In this they are aided immeasurably by Wikipedia's idiot-friendly policy of "verifiability before truth".

So far, at Adolf Hitler, the lines of defense seem to be holding (see also the article's Talk page). At Alois Hitler, I am all alone. Help in reverting the insertion of this garbage would be appreciated. Also, at the Talk page for Haplogroup E1b1b someone asks about this. It would be nice if a population geneticist (well, I can dream) could provide a scientific answer there, so that one could then point people to it.--82.113.106.29 (talk) 02:58, 26 August 2010 (UTC)


 * Firstly, I think you're in the wrong place; the reference desk is for asking questions, not for getting editing help.


 * Next, I removed the personal comment about Gibson; I know it was a joke/quote, but still: personal attacks are not tolerated. I'd also prefer if you didn't refer to editors as "ignorent doofuses", and suchlike; I sympathise with you, I know that it can be frustrating, and know it is hard to stay calm, but please try.


 * I suggest you read WP:DISCUSS, and possibly try Content noticeboard, perhaps request page protection, or whatever. Best of luck,  Chzz  ► 03:15, 26 August 2010 (UTC)


 * Why shouldn't Wikipedia cover the news? A single marker may not be proof, but it's undeniably some degree of scientific evidence, supporting a speculation that existed long before the PCR machine.  If it gives people some mirth, so much the better.  If people had been quicker to laugh at Hitler in former times, there might be more of these markers in Germany. Wnt (talk) 14:49, 26 August 2010 (UTC)


 * Wikipedia should take extreme care in covering the news. Particularly when 'the news' is reporting on scientific findings &mdash; the reader of the typical newspaper might be forgiven for believing that we've discovered the cure for cancer every year since 1980, or that porn stars are a worthwhile source for information about vaccination and developmental disorders.  There's a nasty tendency for a neutral, watered-down, cautious hypothesis in the peer reviewed literature to become a slightly-firmer off-the-cuff casual quotation in an interview, which in turn becomes a blazing, absolute, out-of-context headline for tomorrow's paper.  TenOfAllTrades(talk) 15:07, 26 August 2010 (UTC)


 * This is true, but I believe "extreme care" should consist of balancing one source against another. Mass delusions such as John F. Kennedy assassination conspiracy theories or Moon landing conspiracy theories are notable and worth reporting, even if completely unsupported by fact.  Half-truths are also worth reporting, and best reported by including the necessary background for readers to see the whole truth. Wnt (talk) 16:21, 26 August 2010 (UTC)

The point I would like to make is that Hitlers body was never found, and the Russian cold war claims to have part of his skull are dubious at best. So they could not have done this test, as there is nowhere to get the DNA sample from. Hence in my opinion, the claim is nulkl and void and should not be included in the respective articles. —Preceding unsigned comment added by 195.89.16.154 (talk) 19:16, 26 August 2010 (UTC)

Argh! "Verifiability before truth" is your savior here. Arguing the "truth" of this is impossible - neither you, nor the other editors you're arguing have any clue what the truth is. "Truth" as a standard fails you miserably here. We don't know the truth. However, the "verifiability" standard is of immense help here.

The available 'reliable sources' don't say that Hitler was Jewish - they say that such-and-such scientist performed some test that produced some result that may be interpreted as suggesting that Hitler could have been Jewish. That is also "a fact". Someone did say that. However, until that scientific paper has been published in a reputable journal - you can't report that what the paper says is "true". When that paper emerges, we can read what it actually says (which, I'm pretty sure won't be "Hitler was Jewish" but rather "Hitler's DNA shows some genetic group or other") - and report on exactly that. Remember - WP:SOURCES says that: All of these say that our articles cannot say "Hitler was Jewish" - only that "Megan Gibson says that Hitler was Jewish"...or whatever it is she actually says. Once you have established that fact, two other Wikipedia policies swing into play: Firstly that you can only publish her opinion if it's Notable...secondly that you may not give fringe theories undue weight. This is a very new finding - doubtless only one scientist has done the test - doubtless that scientist didn't come to the actual conclusion that the junk press came to. So perhaps mentioning the TIME article AT ALL is giving it undue weight. One last thing to note is that Wikipedia is not a newspaper. We can take our time over considering these things. We don't have to rush to add this to the article - we are supposed to sit back and let events play out and then report on the results when they are better settled and accepted. WP:NOT says:
 * "''Articles should be based on reliable, third-party (independent), published sources with a reputation for fact-checking and accuracy'" - that last phrase is important here - some junk TV news show or some sensationalist "It's Science" column don't do that - so they don't count.
 * "Academic and peer-reviewed publications are usually the most reliable sources where available, such as in history, medicine, and science..." - so go to the source publication and get your information there - NOT in the TIME magazine article.
 * "Where a news organization publishes an opinion piece, the writer should be attributed (e.g. "Jane Smith has suggested...")" - so you can say "Megan Gibson of TIME magazine says XYZ is true" - but don't say "XYZ is true" unless you have something with the solidity of a scientific paper published in a reputable journal.
 * "Exceptional claims require exceptional sources..." such as: "Claims that...would significantly alter mainstream assumptions, especially in science, medicine, history, politics, and biographies of living persons."
 * "Wikipedia considers the enduring notability of persons and events. While news coverage can be useful source material for encyclopedic topics, most newsworthy events do not qualify for inclusion.".

SteveBaker (talk) 20:49, 26 August 2010 (UTC)
 * I think you're quoting that out of context, but we shouldn't argue policy here. Though I think the news reports deserve to be reported in the article with or without detail, I think this entry here could be deleted now without loss, because we don't yet have anything to analyze. Wnt (talk) 21:59, 26 August 2010 (UTC)

Mirrors
Glass, if heated enough, can be forced to change shape. Is it possible to heat a mirror (it's plane) and press it someway to make it into a concave mirror without damaging it's ability to reflect ? Jon Ascton   (talk)  06:27, 26 August 2010 (UTC)


 * Mirrors come in many different forms; mirrors with glass are usually silvered glass (a layer of silver deposited behind the glass); since silver and glass melt differently, melting and forming a curved mirror from a straight one may not result in the desired end. Instead, you would probably isntead use a normal, unsilvered piece of glass, shape that, and THEN apply the silver.  -- Jayron  32  06:43, 26 August 2010 (UTC)


 * Thanks !! Are you sure ? But how does one turn glass into mirror ? Is it possible to achieve full mirror brilliance that is required in optical appliance? —Preceding unsigned comment added by Jon Ascton (talk • contribs) 07:30, 26 August 2010
 * You can buy sheets of mirrored plastic which are easy to bend, and might perhaps melt into shape also. Shaving mirrors are already concave. 92.15.13.237 (talk) 10:54, 26 August 2010 (UTC)
 * Optical quality mirrors are made by Sputter deposition of aluminium on a glass or metal base. Reflections from this surface are free of the loss and internal reflections that glass introduces. Cuddlyable3 (talk) 12:35, 26 August 2010 (UTC)
 * I watched a demo where they poured some kind of chemical (something based on silver nitrate I believe) into a flask and made it into mirror instantly. Ariel. (talk) 18:34, 26 August 2010 (UTC)
 * this and this telescope both use a liquid mirror, where the mirror is continuously spun to form a concave shape at a temperature above its melting point. ~ A H  1 (TCU) 18:40, 26 August 2010 (UTC)
 * The key here is that it's not the glass that's doing the reflecting. In fact, in most optical applications, you go to great lengths to eliminate any reflections from the glass.  In the case of a mirror, it's the backing that does the reflecting.  The glass merely serves as a suitably stiff medium to hold the mirrored surface still - and perhaps to protect it from damage.  If you want a flexible substrate, use something like mylar film.  I used to work on those big flight simulators that the airlines use to train their pilots.  Some of those use gigantic toroidal-section mirrors and rather than make them out of glass, they make an accurately shaped frame to hold the mylar and apply a partial vacuum to pull it into the desired shape.  The result is super lightweight and really nicely reflective (although perhaps not to the standards required by large telescopes, for example.  Altering the amount of vacuum applied would alter the curvature and thereby allow you to dynamically adjust the focal length. SteveBaker (talk) 20:25, 26 August 2010 (UTC)
 * I think one more thing needs to be said, which is that the thin layer of reflecting metal would be relatively fragile compared to the thicker piece of glass. So if you took a mirror, heated it up, and started bending, what would most likely happen is that you'd damage the reflective coating so it wasn't a mirror any more.  So the answer is that it's possible but not practical.
 * Also, starting with something like a mylar sheet mirror will only be practical if you want curvature in one direction -- that is, a distorting mirror that changes the shape of objects. To convert a flat surface to a spherical curve, like for a shaving mirror that enlarges the reflection, you'd have to redistribute the mass so the thickness would not be uniform.  Not simple.  --Anonymous, 22:32 UTC, August 27, 2010.

Kalam argument page needs science help
The section of the Kalam argument page dealing with it's scientific objections needs help to make sure it's free of bias. The scientific viewpoint there is severely under-represented. If anyone wants a small fun project and exercise in wiki diplomacy, this might be a good one to take a stab at.

One specific issue I see right now is that the arguments about causation are unfairly and misleadingly framed. A question of causation is falsely deflected into a question about energy. That is not what Stenger argues, or what the argument is about.

I'm currently away at college and classes just started so I won't be able to work on this, but it really does need some help. Best regards, -Craig Pemberton 06:29, 26 August 2010 (UTC)
 * I think the best thing to do with that article is to merge it with Teleological argument. Cuddlyable3 (talk) 12:18, 26 August 2010 (UTC)


 * The article on the Hartle–Hawking state could use elaboration; perhaps that would help.


 * I don't understand why a beginning for the universe is so crucial to the argument. It would seem that a universe with an infinity of past time offers an infinity of opportunities for organisms to arise; hence any given organism is not the largest, nor the wisest, nor the most powerful; hence a God must exist.  At least to the standard of evidence, such as it is, otherwise being used here.


 * I am greatly skeptical of the idea that the Big Bang represents a beginning of time - to me, it seems like a mathematical singularity, infinitely hot, infinitely dense, infinitely fast-moving particles making an infinite number of interactions. To me it seems fairer to assume that time in the subjective sense is logarithmic relative to in the physical sense.  In other words, once the universe was smaller than a cesium atom or a wavelength of light; but that only means that those physical laws and objects were irrelevant at that time, not that "nothing happened" and time hadn't started.  The focus of physicists on "eras" of the universe in the first fractions of a second indicates just how much subjective time those tiny fractions actually comprised... Wnt (talk) 16:53, 26 August 2010 (UTC)
 * The big bang as such an infinitely dense singularity follows from general relativity in the absence of QM, but with QM we just don't know. With QM it could have started from literally nothing. "The Penrose-Hawking singularity theorems require the existence of a singularity at the beginning of cosmic time. However, these theorems assume that general relativity is correct, but general relativity must break down before the Universe reaches the Planck temperature, and a correct treatment of quantum gravity may avoid the singularity."-Craig Pemberton 23:58, 26 August 2010 (UTC)
 * Hmmm - in the last paragraph of "Objections and criticism", Craig needs to read the definition of the word "spontaneous": Self generated; happening without any apparent external cause.
 * The thing about articles like this is that we aren't here to prove or disprove the argument. We're primarily here to document what people have and have not said about it - what experiments have been done to prove or disprove it, etc.
 * Stenger's argument about quantum theory does indeed blow away the first premise on which this tottering edifice is founded...but even without that, saying that everything has to have a cause - and that we're going to arbitarily label this cause as "God" is a bit fraught. And going from that to the idea that this "cause" must be "personal, uncaused, beginningless, changeless, immaterial, timeless, spaceless, enormously powerful, and enormously intelligent being" simple doesn't follow from the argument.  Indeed the argument of "First cause" says that for a god to exist, there has to be a cause for god.  If god can be "causeless" then why not cut out the extra step and simply declare that the universe is "causeless"?  And how the heck you decide that "enormously intelligent" derives from that is nuts!  This "first cause" might be a simple, mindless physical process...a massively improbable quantum event of some kind perhaps.
 * But we are not here (in article space) to challenge what people have said. We need to report that he said these things - point out what other people have said - and put the argument into a suitable context in order that we don't give it undue weight or imply that it is in any way "true".  The most I'd change in this article is to say somewhere in the introduction that this is not the view of mainstream science.
 * SteveBaker (talk) 20:19, 26 August 2010 (UTC)

Constellations
Hello. I'm am just starting to get in to amateur astrophotography, and I don't yet know much about constellations and stars. Could someone go here and here and make sure all the notes on stars are right and any more if possible? Thanks, --The High Fin Sperm Whale 06:38, 26 August 2010 (UTC)
 * A great piece of software I use which you may or may not be familiar with, but would definitely assist you is called Stellarium (computer program).Vespine (talk) 06:47, 26 August 2010 (UTC)
 * I once pointed a camera at Orion for 15 seconds using a camera through a window without any kind of tracking device or piggyback mount whatsoever. The result is here (top-left "star" is Mars). ~ A H  1 (TCU) 18:37, 26 August 2010 (UTC)
 * I think you're camera must have been bumped during exposure. The first of my pictures used a 15-second exposure and the second used 5-second, and the trails aren't nearly as long a yours. Also, you can see in yours that the stars look a bit like tadpoles, with a bright head and dim trails, indicating it was bumped. Can anyone help with my original questions? --The High Fin Sperm Whale 18:51, 26 August 2010 (UTC)
 * It could also be the camera's image stabilization feature. Those need to be turned off before taking astronomy pictures or gyro drift will cause the camera to adjust the mirror position to "correct" for camera movements that aren't actually happening. (The exception to this rule is cameras or telescopes specifically made for long exposures. They've got better gyros.) APL (talk) 19:21, 26 August 2010 (UTC)
 * Well, thanks for the tip Astro. And thanks Vespine, for introducing me to Stellarium. --The High Fin Sperm Whale 19:36, 28 August 2010 (UTC)

Astrology
I have heard that some Universities in India teach astrology as a science subject. Is that true ? Jon Ascton   (talk)  07:33, 26 August 2010 (UTC)
 * A quick Google search tells me that it is true Zzubnik (talk) 10:15, 26 August 2010 (UTC)


 * Yes, and the Government of India/University grants commision has had a official policy guidelines on vedic astrology departments since 2001 this | page has a list of Indian and foreign universities where vedic astrology is taught. Diwakark86 (talk) 11:19, 26 August 2010 (UTC)


 * But astrology is not science

Minimum-Diameter Nuclear Weapon Physics-Package
Hi. I want to know what is the minimum possible diameter of the physics-package of a nuclear weapon; i.e. not the diameter of the narrowest physics-package ever designed, but rather what is the smallest diameter that is scientifically possible for a physics-package? Please note that this is a question of scientific/technical curiousity - not a homework question. Addendum: A nuclear physics-package compliant with the following parameters is sought. Thank you in advance to all respondents. Rocketshiporion
 * 1) Diameter of between 40mm (about 1.575") and 80mm (about 3.145")
 * 2) Length not exceeding 320mm (about 12.6")
 * 3) Any yield above one ton is acceptable.
 * 4) Normal to high shelf life is required, as this device is intended for interplanetary (not interstellar) propulsion.


 * It's worth looking at yields of actually designed weapons, as they do probably give some indication as to the trade-off between diameter and yield:


 * {| class="wikitable"

! model ! diameter ! length ! max yield
 * W48
 * 6.1"
 * 33.3"
 * .072 kt
 * W33
 * 8"
 * 37"
 * 40 kt
 * W54
 * 10.75"
 * 15.7"
 * 1kt
 * W9
 * 11"
 * 55"
 * 15 kt
 * W19
 * 11"
 * 55"
 * 15-20 kt
 * }
 * W19
 * 11"
 * 55"
 * 15-20 kt
 * }


 * Now the high yield of of W33 might be exaggerated -- that's probably its theoretical yield with full boosting, and its non-boosted yield is probably around 10kt. But I suppose there's no reason to ignore boosting, a priori. But I'm a little dubious of 40 kt.
 * Six inches is pretty dang small for a nuclear weapon. This is not just because of the fissile material, but because of reflectors, shielding, etc. The itty-bitty W48 is actually an implosion weapon — probably a tiny core of Pu with a very clever linear implosion explosives package. The W33 is apparently a gun-type weapon. The 8" and 11" diameters are obviously constrained to the width of the artillery they are meant to be fired out of.
 * Could you go smaller than 6? What's the acceptable yield before you start calling it a fizzle weapon? (The W48 technically does have fission yield, but it looks like almost none of its plutonium fissions.) --Mr.98 (talk) 13:03, 26 August 2010 (UTC)


 * Incidentally, if you posted this at Talk:Nuclear weapon design, you'd probably get better answers from people who love to run back of the envelope bomb calculations. --Mr.98 (talk) 13:08, 26 August 2010 (UTC)


 * I see that oil well includes a cute video of a 10-inch casing. I wonder if this means that someone really could have plugged the BP well with a nuke, if equipped with an unusually healthy dose of mental instability. ;) Wnt (talk) 16:44, 26 August 2010 (UTC)


 * If your application can tolerate the lower shelf life (and the hugely greater cost), there are several isotopes with a lower bare sphere critical mass than Plutonium; some of these may be suitable for a nuclear explosive. The Nuclear Weapons FAQ discusses the possibility of a Californium primary, and says "a nuclear device smaller than 2 kilograms or so using Cf-251 is almost certainly impossible." If you combine that with the technology used to design the prolate Komodo primary for the W88 (which, like your question, stresses lower diameter in one dimension as a major design criterion) that stands to be tiny indeed.  Part of George Dyson's book on Project Orion (nuclear propulsion) talks about Freeman Dyson and Ted Taylor considering how to make nuclear devices as small as possible; if memory serves Dyson refuses to say how small they thought they could go, and Taylor's subsequent advocacy partially surrounds the dangers of very small nukes. -- Finlay McWalter ☻ Talk 18:03, 26 August 2010 (UTC)


 * Also take a look at suitcase nuke. ~ A H  1 (TCU) 18:32, 26 August 2010 (UTC)
 * Perhaps I'm missing something, I know very little about nuclear weapon design, but the OP didn't ask for a small nuke. They asked for the smallest possible diameter. My assumption (which could be incorrect) was they don't care about the length. In the real world, it's unlikely anyone would design a ultra thin but long nuke (although the OP said they don't care if anyone is ever likely to design it) And there are clearly limitations which prevent an extremely smaller diameter nuke, no matter how long, in particular, how well you can compress the cylindrical mass. I wonder if this is a difficult question to answer, because no one is likely to be interested in designing something like that so there are potentially lots of unknowns. But it seems to me concentrating on mass or size is partially missing the point, at least as I understood the OP's question. Nil Einne (talk) 18:56, 26 August 2010 (UTC)


 * I suppose it somewhat depends on how you're going to deliver it. Could you not have a very long, thin mass of plutonium (or whatever) and fire it at a target at high enough speed that it would deform into a more spherical shape on impact and thereby go critical?  It's hard to know. SteveBaker (talk) 20:00, 26 August 2010 (UTC)


 * That's kind of what I was thinking. Especially if you were happy with a very inefficient yield. I could imagine having a reeeeeeeally long gun-type that was verrry thin and used clever engineering to accelerate the Pu or HEU to fantastic speeds before colliding it either together or just smashing it into something undeformable so it all compressed. It seems like it would be very hard not to get some fission yield that way, e.g. 10-100 ton yield. --Mr.98 (talk) 23:53, 26 August 2010 (UTC)


 * Clever indeed! It would seem that in a case like that, forgetting to "carry the one" or something could turn your gun into a dirty bomb sitting right in your lap (figuratively speaking). Matt Deres (talk) 13:17, 27 August 2010 (UTC)
 * Well, you always run that risk if you don't take care with fissile material. --Mr.98 (talk) 14:11, 29 August 2010 (UTC)


 * Please do not attempt nuclear explosion-based propulsion. Project Orion concluded that explosions would be a sub-optimal means of nuclear propulsion, and proposing them will make a lot of astronomers unhappy for the same reasons they don't like light pollution here on Earth. Please see that latter article and these ten speculative atomic rocket concepts from NASA from its external links. Why Other (talk) 02:25, 27 August 2010 (UTC)
 * Project Orion was not cancelled because it was sub-optimal, it was cancelled because of the Nuclear Test Ban Treaty and also because there was no economic or military need at the time for the huge payloads that Orion could deliver. There is no reason not to discuss an idea whoever it is making unhappy.  Should be an advantage to the antis since discussion will tease out the drawbacks, or else overcome them.  Sp in ni  ng  Spark  14:32, 30 August 2010 (UTC)
 * Honestly, vaporizing part of your hull isn't the most efficient use of nuclear energy for propulsion. It would be much better to heat propellant fluids.  Yes, I've seen today's XKCD and no, it does not accurately represent the subjective term "fast." Get used to the idea of generation ships, deep freeze, and slingshotting around planets if you want to keep hard science fiction fans happy. Why Other (talk) 19:39, 30 August 2010 (UTC)

Non-magnetic plasma?
I'm wondering if there is some substance that's like plasma but it is non-magnetic and doesn't react to magnetism? I don't mean fire/flame as that's a chain-reaction. I mean just basically an energy/matter kind of substance like plasma, but it's non-magnetic and doesn't react to magnetism (well reacts as much as say a vegeatable). Looking through things like List of states of matter has mostly theoretical options that I can't tell if they're magnetic or not and I can't tell if Quark-gluon plasma is magnetic. Are you ready for IPv6? (talk) 09:08, 26 August 2010 (UTC)


 * I think that to be non-magnetic, the "plasma" would have to consist of electrically neutral particles, in which case it is simply a gas, surely ? Gandalf61 (talk) 10:07, 26 August 2010 (UTC)


 * But very high energy like plasma though? Are you ready for IPv6? (talk) 11:32, 26 August 2010 (UTC)


 * Then that would be a hot gas. I think you may be confused about the nature and characteristics of plasma and the difference between a plasma and a gas. I suggest you read our article on plasma (physics), and then look at some of the examples of natural and artificial plasmas. Gandalf61 (talk) 11:55, 26 August 2010 (UTC)


 * Some kind of High-temperature superconductor? ~ A H  1 (TCU) 18:31, 26 August 2010 (UTC)

The Growth of Knowledge
How do we learn things that we don't know that we want to know?--Alphador (talk) 09:11, 26 August 2010 (UTC)
 * Your question is a bit too broad to get useful answers.if 'we' refers to humanity in general you might want to look at the article on the Scientific method. If you want to know how induviduals learn, look at Learning and Education - Diwakark86 (talk) 10:38, 26 August 2010 (UTC)
 * Sometimes we don't know that we didn't want to know something until we do know it, and then it's too late. An example is what getting old feels like. Cuddlyable3 (talk) 11:53, 26 August 2010 (UTC)
 * I read the question as, 'How do we learn things that we don't know but we want to know' since that made more sense with the section title as 'The Growth of Knowledge'. If the OP wants to know about how unexpected discoveries are made, then there are no answers. Since the discoveries are unexpected there are no fixed methods to follow. you may want to read about Serendipity - Diwakark86 (talk) 12:57, 26 August 2010 (UTC)
 * Answer: painfully.
 * Prof. Gian-Carlo Rota used to say,
 * "Learning is never fun.
 * Having learned is fun!" ;)   Wikiscient  (talk) 18:06, 26 August 2010 (UTC)
 * See learning curve and knowledge. These days, there is the Information age and people can learn from the media (not always accurate) or from the Internet (also not always accurate). ~ A H  1 (TCU) 18:29, 26 August 2010 (UTC)


 * As a species - we mostly use some variation of the Scientific Method - we wonder whether something might be true (we "form a hypothesis"), then we try to think of a way to test whether that is true or not, then we try that test ("perform an experiment") and that tells us whether our idea was true (which makes it be a "Law" or a "Theory") or false (in which case we discard it and try to come up with another idea. If I turn the key and my car won't start, I form a hypothesis ("Maybe the battery is dead") then an experiment ("If I listen when I turn the key and hear the starter motor turning - then it can't be the battery") - so I turn the key and I hear the engine turning over - so that hypothesis is incorrect.  Now I think "Maybe I'm out of gas" - and come up with another experiment ("look at the gas gauge")...and so on until I find an experiment that comes out right - and now I have gained the knowledge of why my car won't start.  Of course we don't think that formally about it most of the time - but that's what we're really doing.
 * 19:55, 26 August 2010 (UTC)
 * In general, it's often accidental; I remember reading somewhere a hypothesis that ceramics were discovered after someone accidentally put a clay vessel into a fire. Nyttend (talk) 21:13, 26 August 2010 (UTC)
 * Short of an E for Effort time viewer, I don't see a way to tell, but it just doesn't seem likely. Remember being a kid?  How many more things are fascinating than a fire, and how many things can you do with a fire that are more fascinating than finding things to put in it and see what happens...? Wnt (talk) 22:06, 26 August 2010 (UTC)
 * To follow up on that, I should add that I think a lot of good science is done that way:
 * Identify something new you can do with the tools available to you
 * Try it and watch what happens ("experiment")
 * Look at what happened more closely and see if you can spot any unexpected or useful effects (devise a "hypothesis" that the experiment caused them)
 * Do the experiment differently and see if you can change what happens ("hypothesis" tested)
 * Try this repeatedly and make sure you can count on it ("conclusion")
 * Now this is different from the scientific method as often written, because the "scientific method" is a religion. Nobody tests it.  Nobody proves that knowing it makes you a better researcher.  The principal purpose of this religion (like many of a low order) is so that you can feel good about yourself and your technological society and look down on the primitives; you have faith that Dioscorides or Susruta or Ge Hong didn't know this crucial faith, so even if they invented mainstay medicines that have been used until the present day, it was just by accident.
 * So I won't say my version is "better" than others, but I will say that the idea of putting the hypothesis first and the experiment later is often a lie. Lots of researchers will do this out of conventionality, describing their work altogether out of its actual temporal and causal order, in a way to assuage peer reviewers as being a grand plan, when in reality one of their kids spotted a jawbone poking out of a cliff, or they saw a new gene chip in a catalog, and things went from there. Wnt (talk) 22:40, 26 August 2010 (UTC)


 * Not really. You can do observations of experiments - but they don't tell you anything until you form a hypothesis to explain why that happens - and devise a way to test that hypothesis.  For example - I might give you the series of numbers 1,2,3,4,5,6 - you might "observe" that these are consecutive numbers and form the hypothesis that I am counting something.  However, you need to do an experiment to test that hypothesis...like waiting to see if the next number is 7.  When you discover that the next number is actually 10 - you must abandon that hypothesis and come up with another one...perhaps that I'm listing the factors of the number 60.  So that the next number should be 12...when the next number I give you actually is 12, you have some evidence that your new hypothesis is the right one.


 * There isn't any particular reason - much less "proof" - that the scientific method is the best way to gather knowledge. But it is far and away the most successful way that we have to explain the world.  All previous methods left humanity in more or less the same condition.  It's only with the establishment of scientific method that technology has really taken off.  All the wonders of the modern world would have been impossible without the scientific method.


 * The method is widely considered to be "the right way to do things" because it works really, REALLY well. Consider that computer you're sitting in front of - it only works because we understand quantum theory and can therefore build flash-memory chips using quantum tunnelling.  No amount of just observing nature would have gotten us that.  It too directed study - efforts to prove or disprove a hypothesis.  But the scientific method certainly isn't the only way - and perhaps we'll one day find a better way.


 * Simply observing - without taking the hypothesis/experiment approach leads people to all sorts of wrong conclusions. Consider 'dowsing' - walking around holding a 'Y'-shaped stick and hoping to find underground water (or whatever).  Someone walked around with a stick - 'observed' that they found water and jumped to the conclusion that they had discovered some major new phenomenon.  They didn't take the next step - devise an experiment to determine whether the stick had anything to do with finding the water...hence, bad conclusion. SteveBaker (talk) 23:32, 27 August 2010 (UTC)


 * To answer the OP, there's various ways, depending on how you define "knowledge" and "learning", one could approach the question.
 * There's the purely practical, that is how do we go about teaching things to people: that's covered by the subject of pedagogy.
 * There's the purely metaphysical, that is how do humans in general know things, how do they know they know things, etc. That's the subject of epistemology.
 * Then there are people who have combined the two. The educator/philosopher John Dewey has some excellent works which combine the practical and metaphysical (a branch of philosophy called "Pragmatism") and deal directly with combining pedagogy (that is how to teach) with epistemology (that is, how we know stuff).  I recommend Democracy and Education and How We Think as some great Dewey works to read.  His earlier works, like Democracy and Education, were more practical in nature; he gets more esoteric in his later life, like Knowing and the Known.  I still pull out Dewey once in a while.  He's very readible; indeed some of his works should be mandatory for anyone considering becoming a teacher.  -- Jayron  32  02:37, 27 August 2010 (UTC)
 * My reading of the question "How do we learn things that we don't know that we want to know?" is that the part "things that we don't know that we want to know" is referring to things that we may be completely unaware of or wouldn't necessarily recognise as having value in terms of increasing knowledge even if we were looking right at them e.g. going from 'flowers are colorful' to 'bees can see colors' took centuries. I thought the question touched on the 'things that you don't know that you don't know' issue like a knowledge landscape where constraints in your exploration methods can result in you not seeing a hill or even missing an entire continent. I think Diwakark86's answer partially addressed this interpretation i.e. randomness helps.  Sean.hoyland  - talk 06:35, 27 August 2010 (UTC)

When is the Age of Aquarius?
How many years from today will we begin to enter the Age of Aquarius? If we see the Aquarius constellation in the nightsky, does it mean we're in the Age of Aquarius? 99.245.73.51 (talk) 11:46, 26 August 2010 (UTC)


 * See Age of Aquarius. The beginning is debatable.  We may be in it now, getting close to it, or still 400 years away. -- k a i n a w &trade; 13:52, 26 August 2010 (UTC)
 * Obviously it must have began when God arrived on Earth; unfortunately, the Government killed him, and his successors fled to Anatolia, triggering the apocalypse. But that was a long time ago - we'll all be okay and probably won't have a god come back to trigger another apocalypse until the next Age, when god returns in the form of a sea goat. In actual fact, there is no clear definition of this sort of "age" in a scientific context.  The astrological and mythological parts are loosely based on precession of Earth's orbit - a fairly good overview can be found at the Astrological age article.  All zodiacal constellations can be seen over the course of a 12-month cycle; so it's not sufficient to just "see" the constellation - astrologers claim (without explanation) that an age starts when a constellation lines up with something.  Astronomers precisely measure the positions of each star and constellation, (using the equatorial coordinate system); astrologers then ignore these measurements and make nonsense up about alignments.  Nimur (talk) 16:11, 26 August 2010 (UTC)
 * Due to precession and other related phenomena, astrological ages are actually offset. ~ A H  1 (TCU) 18:25, 26 August 2010 (UTC)

T-Rex


Is there any method by which a human could kill a T-Rex with their bare hands? TheFutureAwaits (talk) 12:22, 26 August 2010 (UTC)
 * Since you didn't specify an adult T-rex... It appears we don't really know the size of a T-rex egg but from what I'm reading there's a fair chance it was small enough that someone could carry one. If you carry the egg up a very high cliff and drop it (presuming that counts as bare hands), I wouldn't give the T-rex growing within much hope of survival. You could probably do this with a baby T-rex as well and you may be able to strangle or break it's neck too. Nil Einne (talk) 12:58, 26 August 2010 (UTC)
 * Since there are no living T-rexes, I would say no, it is not possible for a human to kill one with ANY method. Googlemeister (talk) 13:05, 26 August 2010 (UTC)
 * From a DYK entry on the main page early this April: Did you know... "... that T. rex survives underground in Kenya?"  APL (talk) 15:14, 26 August 2010 (UTC)
 * Ah well those probably wouldn't pose to great a problem, though they might give you an infection if you got bit. Googlemeister (talk) 16:19, 26 August 2010 (UTC)
 * Would poisoning count?Smallman12q (talk) 13:52, 26 August 2010 (UTC)
 * I think some sort of Buffalo jump could be your best solution. But it would take some experimentation to figure out how to get it to run into the jump. If the T-Rex was a hunting predator (Most researchers think it was, at least partially, but there's some debate on the subject.), and if T-Rex is at all interested in hunting humans,  you might be able to get him to chase you into the jump. You'd have to find one that a human could get down safely, but a large animal like a T-rex could not. APL (talk) 15:10, 26 August 2010 (UTC)


 * I think humans possess an agility and intelligence unrivalled by animals that tyrannosaurs would normally come into contact with. It don't see any specific reason (apart from complete insanity) why a human couldn't try to jump or climb onto the back of a tyrannosaur, get onto its head, put out its eyes with those dandy opposable thumbs and grasping fingers, then leave it to die a slow and (almost) pitiable death.  (Boys and girls, do not try this at home.  We disclaim all responsibility for rubbage upon trees, bitage by unexpectedly flexible necks, and any injuries consequent to failing to stay on the bull for the full eight seconds) Wnt (talk) 16:40, 26 August 2010 (UTC)
 * I was going to suggest that, but would gouging its eyes out actually kill it directly? Vimescarrot (talk) 17:05, 26 August 2010 (UTC)
 * Well, considering that any action which indirectly leads to the death of a person can be considered as killing them (for legal purposes, and classed as manslaughter), I would say that the person doing the gouging out of the dinosaur's eyes has, to all intents and purposes, killed it (though just not yet - (s)he'll probably have to wait for a bit while an infection of the eyes kills the animal or it runs in front of a truck or something). -- KägeTorä - (影虎) (TALK) 18:11, 26 August 2010 (UTC)
 * Did they have a lot of trucks in the Cretaceous? APL (talk) 18:17, 26 August 2010 (UTC)
 * How else would these bare-handed humans get around? Vimescarrot (talk) 18:26, 26 August 2010 (UTC)
 * APL, no, probably not, but then, they didn't have people either. -- KägeTorä - (影虎) (TALK) 18:29, 26 August 2010 (UTC)
 * You'd pretty much have to jump down onto it. There's no way you'd climb up one unless we're talking about a cold-blooded tail-dragging T-Rex like you see in old Ray Harryhausen movies.
 * It'd be like climbing onto a two-legged elephant the size of a city bus that was actively trying to eat you. Heaven help you if it turns out to be capable of rearing up vertically. APL (talk) 18:15, 26 August 2010 (UTC)
 * I don't know if anyone can know this, but my assumption is that the increased musculature and increased mass cancel out in terms of acceleration, and that riding a T. rex shouldn't really be any harder (!) than riding a rodeo bull. Without the leather strap, that is.  Until it slams you into a wall, anyway.
 * Let's look at this another way. If brave Homo floresiensis could slay a Dragon of the Megalania prisca flavor, perhaps some among modern humans could do this. Wnt (talk) 18:28, 26 August 2010 (UTC)


 * We seem to be working VERY hard to find a way to say that the answer to this is "yes" - when it's pretty damned obvious that the answer is a categorical "NO!"...but that's the way we are here at the Ref Desk...please forgive us! SteveBaker (talk) 19:38, 26 August 2010 (UTC)
 * Who's we? -- KägeTorä - (影虎) (TALK) 00:08, 27 August 2010 (UTC)
 * Hey! I still stand behind my buffalo jump idea!
 * If you could get a T-Rex to chase you then with careful planning you could kill him by tricking him off a cliff.APL (talk) 19:54, 26 August 2010 (UTC)


 * Humans are the greatest tool users on the planet! Why do you want to take away our main advantage in such a one-sided (albeit hypothetical) conflict?  Googlemeister (talk) 19:42, 26 August 2010 (UTC)


 * A T-Rex is structurally very similar to a 50 foot long crocodile with big legs. A person with bare hands can't even kill a 10 foot crocodile, except by wrestling it to a standstill and holding on to it until it starves to death. Looie496 (talk) 23:29, 26 August 2010 (UTC)


 * Would it not be possible to kill a croc using some kind of choke/stranglehold? Brazilian Jiu-Jitsu and SAMBO feature several possibles in their curricula that could possibly be modified... --Kurt Shaped Box (talk) 23:44, 26 August 2010 (UTC)


 * There is at least one instance of a T-Rex coming to an end as a result of a Mini 1275GT and a sycamore tree. Sean.hoyland  - talk 03:49, 27 August 2010 (UTC)


 * I could kill a T Rex with my bare hands. I just need to have a pathogen or a parasite on my bare hands or in them which would be lethal to a T Rex. Then he would eat me and soon after die. A human is to a T Rex as a cricket is to a large frog. A pet frog once got an intestinal parasite from a cricket which cause the frog's rectum/intestine to prolapse (protrude from the anus), and only timely intervention by a skilled vet sutured up the protruding intestine and saved the frog's life.  There were no  vet hospitals in the age of T Rex. Edison (talk) 04:58, 27 August 2010 (UTC)
 * "I could kill a T Rex with my bare hands. I just need to have a hand-grenade or a bazooka on my bare hands." NO! Hands with T.Rex-killing pathogens on them aren't "Bare". That's cheating! SteveBaker (talk) 23:03, 27 August 2010 (UTC)

Creationist Kent Hovind claims that the "dragons" of old were actually T. rexes and were killed by humans by ripping off their arms. And if you believe that, I just happen to have a nice steel tower in downtown Paris that I can sell for a reasonable price.Sjö (talk) 10:22, 27 August 2010 (UTC)
 * Haha! If he really presents that as a serious idea that's great. T.Rex's arms are comically short and stubby, but (for unknown reason) were about as strong as your average forklift.  You might as well try to tear out his teeth. APL (talk) 20:09, 27 August 2010 (UTC)
 * If a T Rex aims to eat you, and there appears to be no way to avoid it, I recommend you yell "EAT ME!!!!" and spit in his eye. Leave the rest to pathogens in your gut and on your skin. He might curl up and die like the Martians in War of the Worlds, since he has no resistance at all to germs evolved over millions of years. Edison (talk) 01:04, 28 August 2010 (UTC)

life on other planets
Is there life on other planets. --Stephendwan (talk) 13:13, 26 August 2010 (UTC)
 * We don't know. See extraterrestrial life. Vimescarrot (talk) 13:42, 26 August 2010 (UTC)
 * It has never been proven, but we really have not looked very closely for life on any other planet except Mars (and even this search has barely scratched the surface of only a small part of the planet), and there are a lot of planets out there, so it is possible. Googlemeister (talk) 14:39, 26 August 2010 (UTC)
 * (edit conflict)See Allan Hills 84001 and exobiology. Remember it's not only planets that may have life. Other possibilities for life in the solar system include Europa, Io, Titan, Enceladus, and Triton. ~ A H  1 (TCU) 18:22, 26 August 2010 (UTC)
 * Those bodies, by any sensible definition, are planets. Well, maybe not Enceladus. --Trovatore (talk) 21:33, 26 August 2010 (UTC)
 * We have not found any - so we don't know. The best evidence we have is from things like the Drake equation which tries to break down the question by asking things like: How many stars are there?  What proportion of stars have planets?  What proportion of planets could support life?  What is the probability of life spontaneously arising on any particular suitable planet?  What is the probability of that life having survived until today?  What is the probability that intelligence develops?
 * The trouble is that there are a lot of unknowns in that equation. If you ask experts in the field what their best guess for those numbers is, the answer turns out that there OUGHT to be life out there somewhere.  But it's very possible that we have the answer wrong.


 * Another thing to consider is whether the universe is infinite or not. We don't know the answer to that question either - but if it turns out to be infinite - then it is absolutely certain that life exists somewhere - and not just any old life.  If the universe is truly infinite then somewhere there are other humans - somewhere there are other humans who have developed computers and networks and have (by an astounding coincidence) created a web site called "Wikipedia" and that there is someone called "Stephendwan" that just asked whether live exists on other planets!!!  Infinity is a very big number!


 * However, if life (and indeed, another "Stephendwan" exists because the universe is infinite, it doesn't help much - because only a finite amount of that infinite universe is "observable" (because the speed of light is a limitation). So the fact that the universe is infinite doesn't help to answer whether there is life that we could ever find out about, visit or communicate with...and that's really the only question that actually matters in any practical sense.


 * So we don't know. SteveBaker (talk) 19:27, 26 August 2010 (UTC)
 * Technically, if the universe is infinite (and some very natural independence properties hold yada yada yada) then it's almost certain that live exists somewhere else. That doesn't mean the probability is less than 1.  A probability of exactly one is not quite the same thing as certainty. --Trovatore (talk) 23:52, 26 August 2010 (UTC)
 * By the same logic, if the universe is in fact infinite, the Occam's Razor is invalid, because there is an almost certain chance that the complicated answer also exists. Googlemeister (talk) 13:30, 27 August 2010 (UTC)
 * Occam's razor is invalid, as a statement about what propositions are true. The right way to think of Occam's razor is as a rule of thumb to guide your working hypotheses.  The simpler explanation is not always closer to the truth, but it's usually the one whose shortcomings are easier to discover.  --Trovatore (talk) 21:22, 27 August 2010 (UTC)

ghosts
How likely is it that ghosts  exist? --Stephendwan (talk) 13:15, 26 August 2010 (UTC)


 * Skeptics like Randi in west and Dr Kovoor in India have setup up cash prizes to challenge the existence of ghosts, and no one has been able to win their money, they think they have triumphed - having proved for once and all there is no spook. The skeptic-flaw here is that he is assuming that the person who knows how to prove ghost will be desperate to win Randi's money ! This thought has never caught any so-called skeptic's consideration that the person with real knowledge might want to hold it as his most safely-guarded secret. This is because the modern skeptic is basically Marxist - he believes that every one does everything for wealth. The Skepticism is not scientific position, its political.
 * The guys who indulge in black-arts don't learn to do feats overnight, it takes years, even lives, and while at it their world-view changes, they are no longer interested in things like money or even fame, this fact is very difficult to accept for modern people, especially westerns.  Jon Ascton    (talk)  06:10, 28 August 2010 (UTC)


 * There is no reliable evidence for the existence of ghosts. Vimescarrot (talk) 13:42, 26 August 2010 (UTC)
 * How likely is it that they don't?Smallman12q (talk) 13:47, 26 August 2010 (UTC)
 * This discussion will ultimately lead to Argument from ignorance.Smallman12q (talk) 13:49, 26 August 2010 (UTC)
 * It is very unlikely that ghosts exist of the sort that you read about in books about haunted houses. Most story-book ghosts would be easily detectable by modern science. We'd have 'em in zoos by now.
 * The more you imagine that 'ghosts' can interact with people, (scare them, chill them, make noises, whatever) the more incredible it is that they've lasted this long with no-one proving their existence.
 * If your idea of a ghost is 100% unable to interact with the land of the living, then of course, there's no way we can even guess at a probability. APL (talk) 15:01, 26 August 2010 (UTC)
 * Any attempted scientific study of ghosts would fall under paranormal and pseudoscience. See ghost hunting, paranormal investigator and Ghost Hunters. ~ A H  1 (TCU) 18:17, 26 August 2010 (UTC)
 * Not at all. It is entirely possible to have legitimate scientific studies into such topics.  A number of entirely legitimate researchers have undertaken to locate the Loch Ness Monster, for example. (I believe Doc Edgerton was involved in such an attempt, but I don't see it in the article, so I may be making that up.)
 * We mostly only hear about the complete nuts with ridiculously lax laboratory procedures because they're the only ones that have positive results. APL (talk) 18:53, 26 August 2010 (UTC)


 * They are about as likely as that there are Pink Piano Playing Aardvarks on the far side of the moon.


 * We have no way to conclusively disprove that there are ghosts - or that there are pink aardvarks. But there is also no reason to expect that either of them are true.  When you come down to it, there are an infinite number of unprovable (or at least almost-impossibly-difficult-to-prove) ideas out there.  That leaves you with a personal choice to make in your life:
 * Assume that all things that are not absolutely disproved are almost certainly true - and behave as if they were true.
 * Assume that all things that there is not a scrap of evidence for are almost certainly false - and behave accordingly.
 * Pick and choose which things you choose to believe in - despite there being no evidence on which to base that decision.
 * If you choose (1) - to believe in all unprovable things - then you'd have to believe that (for example) when you step out of your bedroom door tomorrow morning, there will be a ravenous Tiger sitting there waiting to rip you to shreds. You can't disprove that - so you are bound to assume that there definitely IS a tiger there and stay in bed.  I don't think anyone can do this in practice because you'd also have to believe that a deadly scorpion is hiding in your bed and that in any case you are about to die of a symptomless, undiscovered terminal disease.  You can't honestly live with (1)...it's just not possible.
 * If you choose (3) - to pick and choose what to believe, but without any evidence - then you may choose to believe in ghosts - but not in the tiger outside your bedroom door. The trouble is, that there are a literal infinity of things that might or might not be true - the probability that you choose correctly is quite literally zero!
 * So a rational person chooses (2). Disbelieve in unprovable things until there is at least some kind of evidence.  Since there is no evidence for ghosts - disbelieve in them.  It's the only rational way to live your life.  See Russell's teapot for more discussion of this approach.
 * There is another little part to this. Sometimes you are forced to choose between two different courses of action, depending on some piece of information that you don't have - do you boldly step out of your bedroom door because you have no evidence that there is a tiger out there - or do you hide in your bed forever because you have no evidence that there ISN'T a tiger out there?  In that case, you have to employ Occam's razor - which basically says "believe in the simplest option - unless you have evidence to the contrary".  Since tigers are not endemic in Texas and I've heard no growling and there isn't a circus in town and there was no announcement of a tiger escaping from the local zoo in the news today - it's pretty safe to assume that there is no tiger waiting for me out there.  I don't have proof of that - but it's the simplest explanation for what awaits me.
 * Oh - yeah - there is no such thing as ghosts...trust me! SteveBaker (talk) 19:11, 26 August 2010 (UTC)
 * There are no Pink Piano Playing Aardvarks on the dark side of the moon. Them´s Pink Floyds.  --Cookatoo.ergo.ZooM (talk) 21:17, 26 August 2010 (UTC)


 * There are good reasons not to believe in ghosts (earthbound spirits of the departed, who appear to mortals, walk through walls, talk to them, make the air turn cold, make noises) since such phenomena are outside the system of physical and chemical principles which explain everything else in our world nicely. There is no convincing scientific evidence they exist. Neither of those is a disproof, since our understanding of science has been tweaked substantially in the past decades. The world's best scientist in 1880 had no understanding of many scientific areas every or college freshman learns about today. There could be areas of physics discovered in future years which would be as amazing to us as nuclear energy, the internet, black holes, dark matter, the Big Bang or gravitational lensing would have been to Helmholtz.  There is also the strong temptation for TV producers or charlatans to fake ghost manifestations, so they earn money or gain fame. Edison (talk) 19:27, 26 August 2010 (UTC)
 * I've been doing a lot of reading into the subject of skepticism and belief recently. I don't think the main issue is that "irrational people" choose to believe in ghosts even tho we don't have any good evidence to support that view, like some of the above answers seem to suggest. I think the main problem is that people who do believe in ghosts also believe that we already HAVE conclusive evidence that ghosts exist, and they think WE are the ignorant or arrogant ones for not seeing it. I think they are people who simply have different standards of what qualifies as evidence, they aren't fundamentally different however. I just saw a great doco which illustrates this, it was called Dan Aykroyd - Unplugged on Ufo's. It's a great exercise in critical thinking, I recommend it. In it, there are people (including Dan) who are convinced that we are pretty much constantly visited by alien or trans dimensional beings, the governments of the world know about it and it's imminent that the whole thing will be blown open because they can't keep covering up all these sightings and abductions and stuff... It's incredible! None of those people think they don't have any evidence to support their view, they all think there's mountains of evidence. Every dirty lens, every piece of space junk filmed from ISS, every astronaut that says the word UFO during a space flight, that's all solid evidence to those people. Vespine (talk) 23:53, 26 August 2010 (UTC)
 * It is plainly obvious that UFOs exist. What is absurd is that UFOs are beings from another planet spying on humanity.  Anything in the air is a UFO until you figure out what it is, but you don't hear much about objects that were UFOs and are now identifiable.  Googlemeister (talk) 13:28, 27 August 2010 (UTC)

Carbon Excretion
Is there a way of excreting carbon from the body other than in the form of carbon dioxide in exhaled breath? Would a person doing more work and burning more energy than baseline have a higher percentage of carbon dioxide in their exhaled breath?--160.36.38.121 (talk) 17:09, 26 August 2010 (UTC)


 * I'm pretty sure there's carbon in urine, faeces, sweat and other excretions. When I was doing school biology many years ago we did experiments measuring the composition of exhaled breath, and the proportion of CO2 was indeed higher after some mild exertion. (Breathing hints at this.) AndrewWTaylor (talk) 17:15, 26 August 2010 (UTC)


 * Yes, there is some carbon in nearly everything that comes out / off of the human body, but in terms of changes in human biomass nearly all of it is negligible compared to the 1-2 pounds of carbon that is in the carbon dioxide that the typical person exhales every day. Dragons flight (talk) 17:21, 26 August 2010 (UTC)
 * Depending on diet, a human could excrete 1-2 pounds of solid waste, which could be 50% carbon by mass. This is an ineffective sequestration method, too; and it is not a "negligible" quantity.  See thousands of publications on reducing the carbon footprint of wastewater treatment (some due to energy-use, but a large percentage due to aerobic digestion of the sludge.  A very significant percentage of this carbon can, through decay processes, be re-released to the atmosphere as carbon dioxide - but it is often diluted because (after treatment) the wastewater is dumped back into the environment.  Diluted or not, carbon does not "disappear" - it either remains in solid form (i.e. as cellulose and all the other carbon-containing materials in human solid waste - or it is digested (by bacteria) into carbon dioxide.  Nimur (talk) 18:02, 26 August 2010 (UTC)
 * I wouldn't consider undigested food to be "human biomass". Sorry if my wording was too subtle.  Dragons flight (talk) 18:04, 26 August 2010 (UTC)


 * The Respiratory exchange ratio makes use of related concepts (ratio of exhaled carbon dioxide to inspired oxygen) to estimate metabolic activity. -- Scray (talk) 17:24, 26 August 2010 (UTC)


 * Flatulence and burping both release carbon dioxide AND methane. ~ A H  1 (TCU) 18:15, 26 August 2010 (UTC)

energy question
Humans and all living things have  energy  and energy cannot  be created nor  destroyed but  can change forms   but what happens when   we die  what  happens  too the energy we had. --Stephendwan (talk) 17:39, 26 August 2010 (UTC)
 * It's given to various other organisms via decomposition, or released as heat during cremation. Vimescarrot (talk) 18:00, 26 August 2010 (UTC)
 * Important distinction: "energy" in the not-created/destroyed physics sense isn't the same as "I'm feeling energetic vs tired" sense. I'm not sure if that is relevant to questioner's concern or if already knew it, etc., but I've often seen them confused in these sorts of discussions. DMacks (talk) 18:08, 26 August 2010 (UTC)
 * The decomposers recycle the original bodily energy back into the environment. ~ A H  1 (TCU) 18:13, 26 August 2010 (UTC)


 * Firstly the "Energy" described by spiritualists, fortune tellers, and the like is just superstition or, at best, metaphor.
 * Secondly, the energy you had is still right there, in your corpse. It's not being put to good use anymore because your body has stopped working. Imagine a broken, radio. The radio's battery still has energy, but the radio is no longer capable of using it.
 * Luckily your corpse will rot and all sorts of microscopic bacteria will salvage whatever energy they can. APL (talk) 18:38, 26 August 2010 (UTC)


 * The energy present in your body takes many forms:
 * Gravitational potential energy. When you die, you fall over - and maybe get buried in a deep hole.  This energy turns into heat and gradually dissipates.
 * Thermal energy...your body is warm. When you die, that heat also dissipates out into the environment, making the world a little bit warmer.
 * Electrical energy. In your brain and nervous system - this would very rapidly dissipate into heat.
 * Chemical energy. Many of the compounds in your body are not in their lowest energy form.  If you are buried underground or at sea then much of that is broken down by decomposers or perhaps scavengers - which power their bodies from the chemical energy left in yours.  If you are cremated then almost all of that energy turns into waste heat.  It's possible that you might be buried in such a manner that your body would not decompose very quickly - in which case, in a few million years you might form a part of a new oil reserve somewhere!
 * Mass/Energy. Someone is bound to point out that since E=mc2, the atoms that make up your body have an enormous energy-equivalent.  That's true - but it's most unlikely that any measurable amount of it will be released until the earth is consumed by the sun as it expands in few billion years from now - but by then, it's almost certain that those atoms will have been rearranged and used in a bazillion different ways by other processes on earth.  This hardly counts!
 * There may be other small sources that I've forgotten - but pretty much all all of it goes to powering other organisms or as waste heat into the environment - depending mostly on how your body is disposed of subsequently.
 * Since this is largely a matter of entropy, a more interesting (and potentially uplifting) question is "What happens to the information content I leave behind?" SteveBaker (talk) 18:49, 26 August 2010 (UTC)


 * It should not be assumed that the conversion of chemical to mechanical energy by a body ends with death. It is just the voluntary movements that cease. For a considerable period after death, electrical stimulation can cause the muscles to contract, probably with a greater energy output than is required by the electrical stimulation. Think of Galvani with frog legs, or Giovanni Aldini's 1803 experiments using electricity to make the muscles of George Forster (murderer) move. Edison (talk) 19:14, 26 August 2010 (UTC)

Aurochs
When did the Aurochs go extinct on the Island of Great Britain? Googlemeister (talk) 19:50, 26 August 2010 (UTC)
 * The Porlock Aurochs is dated to 1500 BC, so no earlier than that. Physchim62 (talk) 20:21, 26 August 2010 (UTC)
 * List of extinct animals of Britain doesn't provide a reference, but suggests 1000BC. Warofdreams talk 21:25, 26 August 2010 (UTC)
 * According to aurochs, the last individual animal in the world died out in Europe in 1627. Of course, they're not fully extinct, as the moden ox is the descendant of the species-extinct aurochs. ~ A H  1 (TCU) 18:58, 28 August 2010 (UTC)
 * Yes, but that specimen was in Poland, and cattle are much smaller on average then the aurochs were. Googlemeister (talk) 14:45, 30 August 2010 (UTC)

Sun
Can I view the sun clearly with special goggles from earth? Would I see a huge burning sphere like in pictures of the sun I've seen? Prize Winning Tomato (talk) 19:56, 26 August 2010 (UTC)
 * Yes, but it won't show significant detail unless you're also using magnification. Note that looking at the sun can be very dangerous; consult with someone who really knows their stuff before deciding that your goggles are sufficiently protective. &mdash; Lomn 20:18, 26 August 2010 (UTC)
 * This is even worse than giving medical advice. 92.28.246.5 (talk) 20:52, 26 August 2010 (UTC)
 * No, never do this. Danger! You could easily be blinded or pernamently damage your sight! Do not try this it is far too dangerous! The only safe way would be by projecting the image onto a screen of some kind, or by using a camera and looking at a monitor. Telescopes, binoculars or camera lenses concentrate the energy into a tiny spot on your retinas, and they will burn and be pernamently damaged. Goggles will have little effect. Have you ever tried burning something using the sun's rays and a magnifying glass - that will happen to your retinas, which are delicate. 92.28.246.5 (talk) 20:50, 26 August 2010 (UTC)


 * The details you want to see would be pretty much impossible to view with the naked eye - not to mention that you seriously risk damaging your eyesight by looking directly at the sun. The best way to view the sun is to use an optical device called a heliostat and a solar telescope that can project an image on to a screen.  By projecting the image on a screen, you can clearly image the sun at great magnification without ever looking directly into the optical path (which would be so intense that it could permanently damage your eyesight).  It is true that you can find, buy, or build a filter that can reduce the intensity to sufficiently safe levels - but if you don't know what you are doing, you risk permanent damange.  Like most of science, it's a bad idea to use your own eyeballs as the "test subject" for whether a particular "goggle" / "filter" procedure is safe.  Project the image on a screen.  Nimur (talk) 20:52, 26 August 2010 (UTC)
 * Wouldn't the googles you use for arc welding work for this scenario? Googlemeister (talk) 21:06, 26 August 2010 (UTC)
 * This makes me wonder — how were sunspots first observed? Sunspot says that the first telescopic observations were in the 17th century, but the Chinese started observing them two millennia before.  Nyttend (talk) 21:09, 26 August 2010 (UTC)
 * Science was not always conducted safely. Nimur (talk) 22:40, 26 August 2010 (UTC)


 * I used to have a piece of very dark welding glass through which it is supposedly safe to view the Sun (or at least so it was represented to me). My memory is that it was "grade 14" or something like that but I could be wrong about the exact number.  In normal light it looked like a black rectangle, and if you looked through it at brightly lit objects, you could catch ghostly outlines at best.
 * The Sun looked like a small green disk through it. It's surprising how small the Sun appears when it's high in the sky and you're not being dazzled by it.  I used it to look for sunspots at a time of supposedly high sunspot activity, and I did see a few, I think, but I can't say the sight was all that spectacular given the small apparent size. --Trovatore (talk) 21:15, 26 August 2010 (UTC)


 * All reputable sources will tell you not to rely on a filter. The problem is that in the old days, a child's first telescope would come with a cute little "Sun" filter to screw in.  And every once in a while someone would watch for so long, that the filter would crack and suddenly let through super-hot concentrated light from the telescope, precisely focused on the child's retina.


 * Now speaking as a child who used such a device in blissful ignorance, it was a cute little toy, and you could see the sunspots, but the sun was a plain bright disk. (Actually, not all that bright - I think now and then I might have used the little "Moon" filter instead to get a better view.  Miracle I have two eyes)  The sun looked green because of the filter; no true colors were discernable.  Things like the corona and prominences - don't even think about it.  You could get a better view anyway by projecting the image onto a white surface far from the telescope.


 * Now obviously, wearing a welder's mask and looking straight on at the full sun, without magnifying aids, is pretty darn safe. Believe it or not the eye was actually adapted to look in the direction of the sun now and then.  Looking at the sun during an eclipse is more dangerous because the light isn't very bright and your irises open up, but the light is just as concentrated in the area not blocked by the moon and the cells directly under the remaining crescent get scorched worse than if you stared at the sun normally. Wnt (talk) 21:44, 26 August 2010 (UTC)
 * Until you learn how to make a pin hole projector, or find some welding goggles just go here, awesome pictures almost in real time, taken in different spectra taken by SOHO. There's a half decent spot there now, first one I've seen for a while, it has been the Sun's quiet period for the last few years. Sorry but no, you won't see anything like that with your eyes. Pictures of anything astronomical you see are usually either taken with massive professional telescopes, space observatories, or worst of all "artists renderings".. LOL! Actually, come to think of it, they're like the playboy covers of the astronomy world, i never thought of it like that but that's a funny analogy. They're all photoshopped and stuff, it gives everyone an unreasonable expectation of what it really looks like ... lol.. Vespine (talk) 22:56, 26 August 2010 (UTC)
 * To be fair, the Sun's actually a much 'easier' target than most other astronomical objects. Having both large apparent size and extreme apparent brightness, getting very good images of the Sun (at least, at wavelengths that will pass through the atmosphere) requires equipment that is costly but not out of reach of the (very) dedicated amateur.  Unlike faint, dark-sky objects like nebulae and distant galaxies, one does not need a large-aperture telescope or hour-long exposures to gather enough sunlight for a striking photograph.  Using Meade's Coronado Personal Solar Telescope (500-1000 USD from the manufacturer), which has a 40 millimeter aperture (about an inch and a half), you can get raw images like this.  A good camera, good technique, and careful processing can use the same instrument to extract images like these(!).  If you're willing to cough up five to ten thousand dollars, then you get to the high end of commercially-available dedicated solar telescopes.  These stunningly detailed images were captured using a 90 mm aperture scope with a very good set of filters.
 * As Vespine notes, however, the published images that you see of virtually any astronomical object, the Sun included, will be vastly superior to what you see at the telescope eyepiece. Multiple exposures are taken, and ones with poor detail due to atmospheric disturbances ('poor seeing') can be discarded.  Shorter and longer exposures are taken sequentially and digitally combined, so that bright objects aren't overexposed but faint objects become visible.  Contrast is adjusted to make details stand out.  For solar images, false color is almost always used.  (The hydrogen-alpha filter used for the images I've linked only passes a small amount of red light; the images are then recolored in shades of yellow to look more 'Sun-like', or using a ramp from black&rarr;red&rarr;yellow&rarr;white to give more apparent dynamic range and make features 'pop'.  You can see the red spot on the eyepiece lens in the first link I provided; that's the only color that comes through an H-alpha filter.) TenOfAllTrades(talk) 13:54, 27 August 2010 (UTC)


 * I 100% agree that you must avoid looking at the sun directly and goggles are not a safe bet. So, here is what you do.  You find a room in your house where it's fairly sunny at a particular time of day - and which (preferably) has only one window.  Now you need to almost completely black out the window - either with very thick curtains - or perhaps some black construction paper or cardboard...shut the doors and ideally, the room is now very dark.  Let your eyes adapt to the darkness for a while and then cut about a 1" hole in the cardboard and tape over that a square of kitchen foil.  Now, with a pin, poke a pinhole into the foil to admit a thin stream of sunlight.  Take a piece of white paper and let the stream of light fall onto it.  You should be able to see a small picture of the sun.  This is perfectly safe to stare at without goggles.  You can move the paper closer or further from the pinhole to get a smaller/larger image...but the bigger you make it, the dimmer it will be.  If you want a larger, brighter, image you can enlarge the pinhole slightly and move the paper "projection screen" further back.  If you can get the room nicely pitch dark - and if it's a clear, sunny day - the results will be pretty amazing.  You can even use a camera to take pictures of it - although you'll need to turn off the flash and get the right compromise between size and brightness. SteveBaker (talk) 22:49, 27 August 2010 (UTC)


 * There are certain solar "eclipse glasses" that you can buy that are designed to filter out the sun to a safer brightness. However, sunglasses are NOT safe for this purpose, and using binoculars or a telescope while wearing these glasses can cause the material to be burnt through! Another safe method is using a full-aperture solar filter or a specially-designed amateur-use solar telescope to view the Sun through a telescope, but one hole in the filter can ruin your vision, and the eyepiece filters for the sun can crack and are NOT safe! Finally, #14 arc welder glasses, at least two sheets of unused X-ray sheets, or pinhole projection are also safe ways to view the Sun. However, there is a danger even in using a telescope, binoculars or a magnifying glass to project a focused image of the Sun, as that can burn your retinas if you stare at the image too long, and can even burn the material it is projected onto especially paper. ~ A H  1 (TCU) 18:53, 28 August 2010 (UTC)

Clock
When the seconds hand on a analog clock is rising back to the 12, gravity acts upon it. Will putting the clock on its back (thus removing the gravitational effect on the seconds hand as it both rising to the 12 and falls to the 6) cause the clock to become inaccurate? Prize Winning Tomato (talk) 19:57, 26 August 2010 (UTC)
 * That depends on the design of your clock. If it's a pendulum clock then yes, putting it on its back will cause it to become very inaccurate! If it's a modern electrical clock driven by the vibrations of a quartz crystal, it should have any great effect. Physchim62 (talk) 20:24, 26 August 2010 (UTC)


 * Not significantly†. Note that some clock designs don't work if you lay them sideways, but that's not because of gravity acting on the arms. &mdash; Lomn 20:27, 26 August 2010 (UTC)
 * †Given the millions of various clock designs out there, I'm sure you can find one somewhere that is so poorly designed and constructed as to drastically change its timekeeping under this scenario. For practical purposes and the general case, though, the answer is "no". &mdash; Lomn 20:27, 26 August 2010 (UTC)


 * Sometimes (often) the arms are conterbalanced - they stick out a little in the other direction. In other cases they are so light the clock motor has no problem moving them. In a mechanical clock difficulty in moving the hand may slow the clock, but in a quartz mechanical clock it doesn't - the timekeeping continues, it just signals the motor to move, and then continues counting, it doesn't wait for the motor. Ariel. (talk) 20:50, 26 August 2010 (UTC)
 * Even if it's strictly analog, and even if the hands aren't counterbalanced, I think there would be at most a transient effect, offset later for no net effect. Gravity is a constant, so whatever slowing-down (force lost against gravity) it would cause the minute-hand on the rising route 6→12 would also give a speeding-up on the falling route 12→6 (gravity boosts/reinforces motion). So the first half of each hour would be slightly shorter while the second half slightly longer. But if you're integrating over a closed cycle, the path doesn't matter--no overall change, every hour is the same total length (albeit strangely paced!). It's like a pendulum or a bouncing ball: speeds up every down-motion, slows down every up-motion. Otherwise there's a conservation-of-energy problem (and a perpetual-motion-machine opportunity!). DMacks (talk) 21:21, 26 August 2010 (UTC)
 * Are you sure that works? If it slowed down in the after-6 position, it would spend more time on that side of the clock than on the before-6 side. If it spent 31 minutes on the slow side of the clock, and 29 minutes on the fast side, wouldn't it gain four seconds an hour? (Assuming the fast side loses 2 seconds per minute and the fast side gains 2 seconds per minute.) APL (talk) 22:00, 26 August 2010 (UTC)
 * Why would the fast side (but not the slow side) lose 2 seconds per minute and the fast side (but not the slow side) gain 2 seconds per minute? Are you thinking the second-hand is going faster on one side vs another? My same argument holds there...the second-hand makes a complete circle every minute, so the minute may be asymmetric, but it's still 60 seconds overall. DMacks (talk) 00:13, 27 August 2010 (UTC)
 * Because in this context that's what "fast" means it's not "fast" unless it's gaining time!
 * It's not symmetric because whichever hand has the problem will spend more time going too slow than it spends going too fast. Imagine the extreme case where the problem is 2X. The minute hand would spend 15 minutes on the fast side, and 60 minutes on the slow side for a total of 75 minutes per hour. APL (talk) 01:14, 27 August 2010 (UTC)
 * I assumed force added/subtracted a constant rather than acted as a multiplier/divider--gravity as a vector not a gear-ratio effect and torque/work/etc all are in terms of distance of the action not the time it's acting. DMacks (talk) 08:34, 27 August 2010 (UTC)
 * Hmm.. You're right, that's probably more likely than my way. Ok, we're going to need a defective clock to settle this. APL (talk) 19:50, 27 August 2010 (UTC)
 * That all assumes a rigid mechanism connection (gears, pulleys, etc.) If you add ratchets or other non-linear-mechanical controls (not quite sure what the right term is for these), then you could have all sorts of weird effects. Consider putting the minute-hand on a ratchet: as soon as it crosses over 12, it falls right to 6. As soon as the next catch in the ratchet picks up, it goes back up to 12 at normal speed (with gravitational or whatever else influences). That's a dumb idea...most hour-long meetings start "on the hour", and if anything I'd want the second half to fly by rather than the already-dragging second half:) DMacks (talk) 21:20, 26 August 2010 (UTC)


 * Naturejournal36londuoft 0523.jpg
 * "Escapement" may be the word you want. How does an Omega watch work?  Well, there are loads of tiny parts to account for all these sorts of things - like when the watch is upside-down, or moving, or swinging around on a hand; or when the spring winds down and the force is a bit less than it used to be; and so on.  The tourbillon is the specific part that compensates for gravity (and is considered superfluous in most high-quality designs).  The very word "clockwork" has come to be synonymous with "lots of complicated internal parts that carefully compensate for small details."  A modern electric clock uses a motor and a quartz timer, and a bunch of mechanical ratchets, gears, and escapements.  It uses extra energy (but a miniscule amount) to move hands forward; and the hands catch on the next ratchet or catchment, guaranteeing that regardless of position, each "tick" is a progression by the same amount.  The deviation from "ideal" can be measured to ~ 1 part in 108 on a modern clock; and more expensive clocks are even more accurate.  Nimur (talk) 22:11, 26 August 2010 (UTC)




 * Cool pics. I definitely think Tourbillon addresses the OPs question.   Wikiscient  (talk) 06:11, 27 August 2010 (UTC)
 * WP:OR I once had a very long layover in Heathrow Airport on my way through London to Beirut. To pass the time, I went to the Schaffhausen store, and stared at watches that cost more than my plane ticket - and watches that cost more than my car; I was truly dumbstruck.  (One of the rare times in my life when I couldn't think of something to say).  And a man approached me - not the salesman - but an out-of-work and formerly-famous rock star - and he told me that he understood my confusion, as I stared at watches that nobody could afford.  I told him how I had worked on engineering projects where we used software and electronics to accurately measure time to sub-nano-second precision; how I couldn't understand why a lousy gear-mechanism based on technology from 1759 would have any market value.  And the watch-enthusiast rock-star replied by explaining the complexity of these watches; and how they were not only about technology, but about priorities in life - that sometimes we do things in life not because they are practical, but just because we can.  I think he's still unemployed, but he probably lives on some Greek island in the mediterranean with three yachts and a $90,000 7-jewel watch, anyway. Nimur (talk) 16:01, 27 August 2010 (UTC)
 * Just a couple of observations ... I've seen numerous clocks that spend 31 seconds on the "up" side and 29 seconds on the "down" side, but they still keep accurate time (of course I don't know what APL meant ).  I've seen other battery clocks with weak batteries where the weight of the second hand on the "up" side causes the escape mechanism to miss a "tick" and thus the clock loses time (before stopping completely).    D b f i r s   13:17, 27 August 2010 (UTC)

reading from your peripheral vision
alight and fix your eye on the first word of the next sentence, and try to read the rest of it from your peripheral vision. When I do that I clearly fully see the whole rest of the sentence, so that it seems I would be able to read it without an issue, but of course I can't. I couldn't actually sound out the sentence that it seems to me I easily could have! So, it seems to me there are two possibilities: the "clear image" is a lie by my brain. I sense those words clearly, but the brain is just giving me a general idea of "clear" based on the shapes it sees: it can't really read from the peripheral vision. (so all those clear words are lies, just as what your brain paints into your blind spot is). The second possibility I can imagine is that it is not a lie on the part of my brain that I see those words clearly; I do and with training I can read them without moving my gaze to them. So, which of my conjectures (if either) is correct? 85.181.50.8 (talk) 21:12, 26 August 2010 (UTC)


 * As this is the science desk I'd like to propose an experiment. Can you read text in your peripheral vision if the font size is large enough that you're absolutely sure you can resolve it? APL (talk) 21:16, 26 August 2010 (UTC)


 * Sorry, I'm on a phone right now. Can you?  85.181.50.8 (talk)  —Preceding undated comment added 21:30, 26 August 2010 (UTC).
 * Nah, I'm a bit busy. But when you get off the phone you might want to check out the Vision span article. APL (talk) 21:47, 26 August 2010 (UTC)
 * My guess is that's it's a mixture of your two explanations. Peripheral vision is less precise than central vision, but it is good enough to recognize large single word shapes for most people under the age of 40–50 (and many who are older than that). You could probably do better if you trained yourself – maybe that's one of the things they teach you in spy school – but most people learn to read by looking directly at the text. However, your peripheral vision is not as clear as you think it is (because your brain tends to "fill in the gaps") Physchim62 (talk) 23:04, 26 August 2010 (UTC)

It's closer to the truth to say that the "clear image" is a lie -- except really it's more a lie by omission than an overt lie. In other words, we are predisposed to presume clarity unless we specifically detect fuzziness. As long as something is as sharp as our eyes can resolve, it looks perfectly sharp to us. Regarding the ability to read with peripheral vision, it is extremely poor -- the letters have to be about 10 times as large as usual if they are more than a few degrees outside the fovea. The region of clear vision is roughly the size of your fist held at arm's length -- the dropoff in resolution is not abrupt but it is very rapid. It is indeed remarkable that we have so little conscious awareness of this radical change in our visual capabilities so near the center of our field of view. Looie496 (talk) 23:18, 26 August 2010 (UTC)


 * The central part of your eye is the only part with sufficient resolution to read small print, the rest of the eye has lower resolution - but it makes up for it by being much more light, and motion, sensitive. You can test it by setting your CRT monitor (if you still have one) to a 60hz refresh rate. Next look at it straight on, and it's pretty steady, but look at it from the side of your eye and it will flicker (if you don't have a CRT try to find an old fluorescent light, or maybe even a slow fan). A second test is in poor light - from the side of your eye you see more light than from the center. It's usually very hard to tell that the sides of your eyes don't have a lot of resolution because the eye is so good at rapidly flicking in all directions to give you a good view in all areas. Ariel. (talk) 01:28, 27 August 2010 (UTC)


 * Or, if you'd prefer to just not bother with having anything in the periphery to read, you could look into Rapid Serial Visual Presentation. You can improve your reading speed by about a third that way (note drawbacks though).  Wikiscient  (talk) 05:37, 27 August 2010 (UTC)


 * An interesting way to demonstrate how your mind makes up most of what you see in your peripheral vision based on what you expect is to get some coloured sticks/pens/pencils and get someone to move them into your field of sight from behind you as you continue to look straight. If they ask you what colour it is when you don't know it'll take a while for you to accurately work it out, but if you know it is a certain colour, you'll be able to tell sooner. Smartse (talk) 11:52, 27 August 2010 (UTC)


 * You might also be interested in the semantic priming and saccade articles.  Wikiscient  (talk) 06:14, 28 August 2010 (UTC)


 * When I look at the spot proposed by the OP, all I clearly see is "When I do that I clearly fully the sentence that it seems to me giving me a general idea of spot is the second them". ~ A H  1 (TCU) 18:42, 28 August 2010 (UTC)