Wikipedia:Reference desk/Archives/Science/2009 April 9

= April 9 =

Ethanol Train
I took the family to a tiny nearby town for lunch, which just happened to be hosting some sort of event about an ethanol train sponsored by the EPA. I took my son (who loves trains) to walk around the engine and check it out, but nobody was there to talk to. I've been trying to find more information, but I can only find two things: articles calling ethanol a "train wreck" and articles about a train shipping ethanol that derailed. Can someone point me to some information on the EPA's ethanol train? -- k a i n a w &trade; 03:57, 9 April 2009 (UTC)


 * Making the search more specific by searching for the phrase "ethanol-powered locomotive" avoids the sort of false hits you're talking about. I find one hit that might be relevant, which says a company called AHL-TECH is developing one.  They have a web site at ahl-tech.com.  --Anonymous, 4:07 UTC, April 9, 2009.


 * Or you can exclude terms which are in those false hits. I had good luck with "ethanol train -wreck -crash -derail": . StuRat (talk) 05:50, 9 April 2009 (UTC)


 * Did you? The hits I looked at in that search all seem to be about ordinary trains shipping ethanol.  --Anonymous, 8:28 UTC, April 9, 2009.


 * Hmm, your right. I guess that's a more common meaning of the phrase "ethanol train". StuRat (talk) 12:51, 9 April 2009 (UTC)


 * Don't confuse train and locomotive - try googling for "ethanol locomotive". Bazza (talk) 14:02, 9 April 2009 (UTC)


 * Thanks. Looking through AHL-TECH's site, I have found the train that I was looking at and a note that it will be brought to market in early 2009.  Why it was being unveiled in a town with a population of about 400 people is a bit of a mystery, but not the one I was trying to solve. --  k a i n a w &trade; 14:10, 9 April 2009 (UTC)

Weird example of relative size
I was reading a periodical piece on the new Planck craft when I came across this comparison:

Regions of the sky that today are separated by twice the apparent diameter of the full moon were once packed into a space much tinier than the diameter of a proton...

I've got no problem with the inflation theory itself, but I can figure out why they would choose to use "twice the apparent diameter of the full moon" when explaining relative size. I understand that angular diameter is usually used to describe the size of objects in space, but how is it any more useful/easier to understand than absolute measurements (e.g. the distance from the earth to the moon) in this case? Thanks! 124.154.253.25 (talk) 05:46, 9 April 2009 (UTC)


 * Is it any more useful? I personally don't think so. I'd chalk it up to bad writing. It's true that making sense of things is often done with relative sizes, but a poor choice of things to relate helps no one. --98.217.14.211 (talk) 12:23, 9 April 2009 (UTC)


 * We (using e.g. Planck) observe the temperature fluctuations of the microwave background (CMB) as a function of position on the sky and all the maps of the CMB are therefore presented in angular coordinates. Hence we compare the temperature distribution of the patch in one direction with that of a patch in another direction, some angle away from the first patch. The distance to the last scattering surface, where the CMB radiation originates, is the same for both patches and known, hence we can convert the observed angular separation to the absolute distance between those patches at the time of emission and compare that to the size of the horizon at the time (which we compute as an absolute size). Conclusion is that those two patches were not causally connected, yet the statistical properties of their temperature distributions are identical. (Inflation is a way to solve that problem.) The absolute distances are relevant for the physics, but angular distances are what we actually observe and are easier to appreciate. The diameter of the moon is just a unit of angular separation that everybody has a feeling for. --Wrongfilter (talk) 13:02, 9 April 2009 (UTC)


 * I'm not exactly sure what it is you're asking, but does it help to know that the diameter of the Moon is &frac12;&deg;? So twice that diameter is 1&deg;,. B00P (talk) 07:13, 10 April 2009 (UTC)


 * The question is whether it's ever meaningful to compare an angular size, which depends on the viewer's distance, with an absolute size ("much tinier than the diameter of a proton"). —Tamfang (talk) 09:05, 12 April 2009 (UTC)

ESP
Can we actually believe in ESP ? Has it been proven to exist ? Are feelings like Instinct and hunches scientifically backed? For example, can say a mother possibly know that perhaps an accident is going to happen to her child, who is say a thousand miles away ? What is Science's viewpoint on this ? Rkr1991 (talk) 07:16, 9 April 2009 (UTC)


 * You can believe in what you want, but this is the science desk and if you're talking from a scientific point of view, the answer is no. See extrasensory perception.  The prize offered by James Randi may also be of interest.  As to "How can a mother know", the answer is that she can't.  People imagine things all the time and sometimes, by coincidence, they happen.  --Anonymous, 08:34 UTC, April 9, 2009.


 * Note that not all "instinct" or "hunches" require ESP. For example, a mother who somehow knows her adult daughter is being beaten by her husband likely figured it out by their body language. StuRat (talk) 12:46, 9 April 2009 (UTC)


 * Many many people have been tested for ESP and no one ever comes up with a statistically significant "better than chance" score.
 * As for your mother question, about once a week my mom calls me to tell me she dreamed or was suddenly worried that some horrible accident had befallen me. She's always wrong, I'm always fine, and we forget about it moments later. At any given day the chance of my mother suddenly "knowing" that I've been in a horrible accident are about 20%.  So if I ever really am hit by a car or something, There's a good chance that my mother will have "predicted it", But only because she predicts it every week. Still, it would seem very spooky and she'd probably tell all her friends about it. APL (talk) 13:12, 9 April 2009 (UTC)
 * Obligatory xkcd link. &mdash; Lomn 14:17, 9 April 2009 (UTC)


 * Well it all depends on what you mean by "ESP". Rupert Sheldrake has researched "the sense of being stared at", which might fall under this definition. He has also researched whether pets know when their owners are coming home.--TammyMoet (talk) 13:47, 9 April 2009 (UTC)


 * Pets knowing when their owners are coming home probably only requires hearing. If the owner keeps a regular schedule, sounds like church bells or a factory whistle might be clues.  If the owner comes home at random times, there's still the sound of their car and maybe the garage door. StuRat (talk) 20:03, 9 April 2009 (UTC)


 * Smell may come into play as well. A Quest For Knowledge (talk) 20:24, 9 April 2009 (UTC)


 * ...depending on how strongly their owners smell. :-) StuRat (talk) 00:38, 10 April 2009 (UTC)


 * See this article about confirmation bias. Looie496 (talk) 21:45, 9 April 2009 (UTC)


 * The answer is a clear "No" - there is no such thing as ESP. Since no experiment can reproduce it and no theory exists to suggest how it could exist without large swathes of science being overturned, we have to turn to Occam's razor and say that there is no point in even considering ESP any further until/unless some convincing evidence turns up.  So no.  It doesn't exist.  Rupert Sheldrake's work is naive in the extreme.  He doesn't consider (much less control-for) the super-subtle cues that we can pick up from tiny changes in interreflected lighting & shadowing, our sense of smell (which is better than we consciously think it is), small air currents and so forth.  Any one of those things could be cuing us in to the presence of someone outside of our immediate gaze - and that's plenty enough for a brain that's evolved to be nervous of large predators sneaking up on us from behind.  Hence we have zero experimental evidence (properly controlled experimental evidence, that is) for "the sense of being stared at" - and until we have, that too goes into the "nut job theories" pile along with perpetual motion, astrology and the flat earth theory. SteveBaker (talk) 22:31, 9 April 2009 (UTC)


 * If Occam's razor is so dominant, then why does physics come up with complicated and observationally unsupported theories about things like the Higgs boson, wormholes, singularity rings, parallel universes, gravitons, WIMPs and MACHOs, etc? This is almost analogous to putting a few final pieces into a jigsaw puzzle, finding a piece that fits the picture but has one of the convex-shape parts missing, but putting it there anyway because there are no other similar pieces to be found. Science doesn't want to change existing ideas, known as paradigms, but new observations tend to cause them to get changed anyway, for example the now-accepted theory of plate tectonics and continental drift took a whole 70 years before scientists abandoned work on the conventional theory and switched to the new one. ~ A H  1 (TCU) 01:32, 10 April 2009 (UTC)


 * Well, science proceeds by making a hypothesis - then testing that by experiment - and depending on the result of the experiment, we either turn the hypothesis into a theory - or reject it. ESP (as a hypothesis) has been tested - it's failed and been rejected...many, many times.  So it's done - gone - outta here.  The Higgs Boson is still only a hypothesis - we truly do not know whether they exist or not.  However, the existance of the Higgs would explain quite a lot - so Occam's razor does not apply.  Remember Occams' razor warns us not to needlessly increase the number of unproven things we believe in.  If we believe in ESP, we have to conclude that most of physics as we know it is wrong - and that's a MASSIVE increase in the number of unproven things we'd have to believe in.  However, the Higgs would actually explain a lot of things and lead to a modest decrease in the number of unproven things we'd have to think about.  But science does NOT say that the Higgs exists.  Until we've actually gotten around to doing the experiment, it's just a hypothesis - nothing more.  Wormholes, singularity rings, parallel universes and gravitons are all in pretty much the same category.  Science does NOT have theories (in the sense of "Einsteins THEORY of Relativity") about any of those things - they are all just unproven hypotheses.   So in a sense, we have a four-tiered scale of things:
 * Theories & Laws - which are things we believe to be true. Einsteins theory of relativity.  The three laws of thermodynamics, etc.
 * Hypotheses - which are things that might be true. Things that don't violate any theories or laws - but which have not be proven either mathematically or by experiment.  Good hypotheses explain things nicely and can (at least in theory) be either proven or disproven by experiment.  The Higgs Boson, wormholes, etc, etc.
 * Unfalsifiables - which are things that might be true - but which are not proven and cannot possibly be disproven by any means imaginable. There are an infinite number of unfalsifiable things and we cannot reasonably distinguish between the good ones and the junk because there are no experiments we can do.   We simply cannot continue to keep those things in our heads and Occam's razor encourages us to simply ignore them.  The existance of a god (or gods) is a classic example of this.  You can't ever disprove that - so this is an unfalsifiable hypothesis.  If I claim that there are little green men on Mars - then that is falsifiable.  We can (at least in principle) go to Mars, pull it apart, atom by atom if necessary, and if we don't find any little green men - then the hypothesis is busted.  So that's a falsifiable hypothesis (although it's a pretty crappy hypothesis because it doesn't explain anything - so you may have a hard time getting anyone to do the experiment).  But if I say that there are invisible, intangiable little green men on mars who couldn't be detected in that way - then that's an unfalsifiable.  Parallel universes are another great example of an unfalsifiable.
 * Bullshit - which are things that may once have been reasonable hypotheses, but which have failed the 'experiment' stage. ESP is one of those - it seems like it might explain some odd coincidences - but we've done the experiments - and whenever we do them without cheating or accidentally biassing the results - the hypothesis is disproven.  Things like N-Rays and Cold Fusion come into this category.


 * In less rigorous terms - we'd say that bullshit and unfalsifiables should be ignored. Good hypotheses (the ones that seem promising and which would explain something if shown to be true) demand work from scientists - we have to find ways to sort them into the theories and the bullshit - and that means math and experiments - which is what scientists mostly do when they aren't thinking up new hypotheses.  The Big Bang is a great example of this.  I remember when it was just one of three or four competing hypotheses for the formation of the universe.  Then it gradually became more popular because it seemed to explain quite a few things - then we used a spacecraft to measure the cosmic background radiation - which turned out to be pretty much what the Big Bang hypothesis predicts...and now we talk about "The Big Bang Theory".


 * Another good way to think about this is in terms of "extraordinary claims require extraordinary evidence". If I claim that there is a mass-carrier particle that we'll call the Higgs Boson - then you are quite justified in demanding extraordinary evidence before you'll accept that hypothesis.  So we go out and spend a few billions on a large hadron collider - and (when we get the bloody thing working) we do the experiment - and then we either put the Higgs hypothesis into the "Theory" pile or into the "Bullshit" pile depending on what emerges.  On the other hand, if I claim that I have a dollar in my pocket - that's a very unextraordinary claim - and you might even be prepared to take my word for it - an unextraordinary claim really doesn't need much evidence in order for us to believe it.  But ESP is an exceedingly extraordinary claim - it's far less likely to be true than the Higgs.  But where is the evidence?  We don't have a single experiment to prove it...and we've done hundreds of them.  So it's firmly on the Bullshit pile.


 * SteveBaker (talk) 10:54, 10 April 2009 (UTC)

Coma
What are the reasons that doctors will sometimes deliberately/purposefully place a patient into a medically induced coma? What does this do? What is the benefit? What scenarios (health problems) would typically lead to this medical treatment? How do they induce the coma? Thanks. (Joseph A. Spadaro (talk) 08:24, 9 April 2009 (UTC))


 * The induced coma article is rather short, but did you read it? --Anonymous, 08:36 UTC, April 9, 2009.


 * This sounds like a homework question, of which most of the answers are in the induced coma article. --Mark PEA (talk) 11:48, 9 April 2009 (UTC)


 * One case where this process is used is when a patient suffers from severe burns. The reason is that the pain created by those burns would otherwise require massive doses of pain relievers for months, which would have negative consequences for the patient's health. StuRat (talk) 12:39, 9 April 2009 (UTC)


 * Do you know anyone who has had an operation involving general anaesthesia? Axl  ¤  [Talk]  15:25, 12 April 2009 (UTC)

Powder coated steel
Could somebody tell me what "powder-coated steel" is. What advantages are there of using powder coated steel? Any help appreciated. —Preceding unsigned comment added by 87.115.64.1 (talk) 11:31, 9 April 2009 (UTC)
 * our article on Powder coating may help to answer your question. cheers, 10draftsdeep (talk) 13:44, 9 April 2009 (UTC)

Space and matter/observable vs actual
I was just thinking about the Big Crunch scenario. If gravity ends up being strong enough, and the universe starts contracting, all matter will end up forming a singularity. But what happens to space in this scenario? My intuition is that space is being destroyed as well, but I can't make a logical argument for it. While I'm here, is there a relationship between the observable universe and the actual one? I'm thinking they're the same but would like some reading material to confirm that. Cheers 124.169.159.117 (talk) 11:45, 9 April 2009 (UTC)


 * Our article on the observable universe may be useful. It is not synonymous with the universe.  Dark flow, for instance, is theorized to be caused by the gravitational effects of something beyond our observable horizon. &mdash; Lomn 14:14, 9 April 2009 (UTC)


 * The source of dark flow within the observable universe, otherwise we'd have no way to detect it. We can't see the light coming from it because the light we'd be seeing was emitted when the universe was opaque. — DanielLC 18:01, 9 April 2009 (UTC)

Repairing damage to the vocal cords after the removal of a thyroid tumour
Is there a surgical or other method of repairing a gap in the vocal chords so that anything ingested does not trickle through into the lungs? Someone I know had a cancerous thyroid tumour that became sufficiently large as to put pressure on their vocal cords and ended up distorting them. He is now being fed through a PEG tube. The doctors have said that there is a chance they might heal, but they are from a rather provincial part of the world and there's a chance they are not aware of more advanced options. The ultimate goal is the ability to eat and drink independently. Any suggestions or advice would be most welcome. Referred many people here before, but never used it - quite keen on the experience. WLU (t) (c) Wikipedia's rules: simple/complex 12:23, 9 April 2009 (UTC)
 * Isn't that the job of the Epiglottis, not the vocal chords? Rmhermen (talk) 13:04, 9 April 2009 (UTC)
 * Not sure, I'll ask. The person I'm getting info from is a non-doctor.  WLU (t) (c) Wikipedia's rules: simple/complex 14:49, 9 April 2009 (UTC)
 * Agreeing with Rmhermen, this is definitely the role of the epiglottis, not the vocal chords. — Cyclonenim | Chat 19:22, 9 April 2009 (UTC)
 * Keep in mind that difficulty in swallowing can arise not only from distortion of the anatomy, but also from any neurological problems (which in turn might be caused by local nerve damage). Speech pathologists are often consulted for such problems, and many hospitals have "swallowing teams" which assist in their evaluation and treatment. - Nunh-huh 23:24, 9 April 2009 (UTC)

I am assuming that he had a thyroidectomy to remove the tumor or they instead used Iodine-131 to kill off the cancerous cells. Is that right? These articles (http://www.nidcd.nih.gov/health/voice/vocalparal.htm) and (http://www.merck.com/mmpe/sec08/ch092/ch092g.html) say that a thyroid tumor or thyroidectomy itself can cause vocal cord paralysis; this can lead to dysphagia (difficulty swallowing), causing food to fall into the trachea. A thyroid tumor is capable of pressing on vocal cords (http://www.cancer.gov/cancertopics/pdq/treatment/thyroid/patient). Vocal cord paralysis can sometimes be treated with surgery or injections to fill in the gaps in the vocal cords. The thyroid gland can also compress the esophagus (http://www.chw.org/display/PPF/DocID/22801/router.asp). Do you know the term for the condition that he has? There are many different kinds of swallowing problems (see this Mayo Clinic article (http://www.mayoclinic.org/swallowing-problems/)). One scientific paper talked about dysphagia in thyroid tumor that was related to laryngeal edema (fluid accumulation) and was resolved with tracheotomy (http://jcem.endojournals.org/cgi/reprint/86/11/5148).71.31.105.213 (talk) 04:43, 10 April 2009 (UTC)


 * This question should be directed at the ENT surgeon who is treating your friend. His surgeon has access to the operation notes, scans, and other relevant clinical details. All of this information is required before the surgeon then agrees a course of action with your friend. "They are from a rather provincial part of the world and there's a chance they are not aware of more advanced options." Do you mean that the surgeon may not be aware of other options? If you don't trust the surgeon, you need to arrange an appointment with a different surgeon for a second opinion. [For the benefit of the RefDesk regulars, this question is (in my opinion) a request for medical advice.] Axl  ¤  [Talk]  15:37, 12 April 2009 (UTC)
 * Lovely, thanks very much for the extra info. I'm copying my friend with the info contained here (it's to an IP in Goa, hence the "provincial" part of the world and slow connection, and the hospital is the local rather than an advanced ones in a larger cities).  If I have follow-up questions, I would like to continue to post them but I am of course aware that wikipedia is not a source of medical advice.  I'm not sure what the mores are at Reference Desk so stop me if I go too far.  And thanks again for the links to date, greatly appreciated!
 * Follow-up, I am not sure of the surgeon's awareness of options, but the person I'm corresponding with is a layperson though his brother in law is a surgeon and with him in Goa (though I think his specialty is plastic surgery rather than ENT). The primary non-medical complaint is that he is extremely thirsty and can't drink.  I believe the surgeon who treated the tumour is from a different city and NOT present in Goa and I'm not sure of his current doctor's experience, training or specialty.  WLU (t) (c) Wikipedia's rules: simple/complex 20:45, 13 April 2009 (UTC)
 * I've been given a bit more information, apparently the condition is attributed to damage to the laryngeal nerve during surgery. I don't know if this adds anything beyond what I already have, but one link has been found useful.  Thanks again, I don't think this'll add much to the already extensive information everyone has already provided.  WLU (t) (c) Wikipedia's rules: simple/complex 01:43, 14 April 2009 (UTC)

Major Histocompatibility Complex molecule
Hi all just a quick question: Is the Major Histocompatibility Complex molecule found on the surface of all cells in the human body? Am I right in thinking that the molecule is like a little flag of allegience which flags the cell as 'self' preventing the natural killer cells from attacking the cell? I did read the article on Major Histocompatibility Complex but I am still a little confused. Thanks —Preceding unsigned comment added by 139.222.240.209 (talk) 14:03, 9 April 2009 (UTC)
 * There is not just one Major Histocompatibility Complex (MHC) molecule. The human MCH molecules are called Human Leukocyte Antigen molecules, and there are two main groups of them, called HLA class I and HLA class II. The tissue distribution of class I and class II molecules is very different - class I molecules are found on most, but not all cells of the body. A notable exception - they are not found on red blood cells (or are found in trace amounts). This rather old paper gives some examples of the tissue distribution of class I molecules. Class II molecules are normally found only on the so-called professional Antigen presenting cells, i.e. B lymphocytes, Dendritic cells, Macrophages. We have three types of "classical" class I molecules, HLA A, HLA B and HLA C, and three types of class II molecules, HLA DR, HLA DQ and HLA DP. Most people are heterozygous for each of these molecules. HLA molecules show enormous allelic variation, the probability of two unrelated individuals being HLA identical is very small - that's why it's so difficult to find suitable bone marrow and organ donors. Class I and II MHC molecules share a common structural feature. On their surface are two alpha helices, and between them is a groove. In the groove sits a peptide, about 10 amino acids long. Think of it as a hot dog - the bread on each side is the alpha helices, and the sausage is the peptide.


 * Now for the second part of your question. Some NK cells act the way you describe, and HLA-C is the most important molecule for inhibiting an attack from NK cells. Such NK cells may attack cells that lack HLA molecules altogether, or that lack self HLA molecules (provided certain other molecules are present). Losing HLA expression is one way that cancer cells may escape an NK cell attack. For T cells, however, it works the other way around. T cells will ignore a cell that lacks HLA molecules. They also ignore cells with self HLA molecules containing self peptides (these peptides are breakdown products from intracellular proteins). However, they attack cells that have self HLA molecules containing foreign peptides (such as a virus peptide), or cells that have foreign HLA molecules (such as a poorly matched transplanted organ). --NorwegianBluetalk 15:48, 9 April 2009 (UTC)

LIFE AND DEATH
What is Life and what is death ? Is is possible to give a precise definition of the two? Is it all just about electrical signals moving around, or is it something more? Like, does Science acknowledge the existence of the soul ? With all the modern theories floating around, is it possible to write an equation of life? Have we understood how life first came into existence, and perhaps come anywhere near creating it? What does SCIENCE say about all this? Is death something like an infinite sleep, or is it something more, or perhaps less? I have heard theories like Super string theory and Combined Quantum Gravity (pardon me if i am wrong) claim to explain everything. Does that include life and death? Are we any closer to solving that mystery of finding where we came from? Rkr1991 (talk) 14:46, 9 April 2009 (UTC)


 * From a scientific perspective, our articles on life and death should be more than sufficient. Note that there aren't good bright-line definitions, and much of what you ask is better suited to philosophical discussions.  As for the last part, various "theories of everything" are concerned with unifying the three fundamental interactions, not solving all thought arguments and religious conundrums. &mdash; Lomn 14:53, 9 April 2009 (UTC)

I would say this is dodging the question. What the articles define are the characteristics of life, but not what it is! And while the aim of any theory is to explain every natural phenomena around us, why not that include life? Surely the concept of life is as natural as say stars or lightning, not philosophical! Just because the theories don't bother to worry about these phenomena, as one of the readers pointed out, doesn't mean they shouldn't or can't! Rkr1991 (talk) 15:01, 9 April 2009 (UTC) —Preceding unsigned comment added by Rkr1991 (talk • contribs) 15:01, 9 April 2009 (UTC)


 * If the question "what is life?" is not synonymous with "what are the defining characteristics of life, and how is it distinguised from non-life?", then you're not asking a scientific question. So yes: it is philosophical, and it's not within the realm of scientific theory.  Fortunately, people have asked us about the meaning of life many many times.  There should be more than enough opinions there to suit you, and if by some chance there are not, Google yet remains &mdash; Lomn 16:01, 9 April 2009 (UTC)


 * "Is death something like an infinite sleep, or is it something more, or perhaps less?" No, it's not like sleeping. I like the following quote: "I do not fear death, in view of the fact that I had been dead for billions and billions of years before I was born, and had not suffered the slightest inconvenience from it." which may or may not have been said by Mark Twain.  A Quest For Knowledge (talk) 18:06, 9 April 2009 (UTC)
 * Over 30 years ago, Lyall Watson wrote books on this subject. Two I can recommend are Supernature and The Romeo Error. Despite the passage of time, I don't think any modern discoveries have added to his work on the nature of life and death. --TammyMoet (talk) 18:18, 9 April 2009 (UTC)


 * What is Life and what is death ? - Sadly, this is one of those "I know it when I see it" kind of things. There are 'creatures' that are so unbelievably primitive that it's really tough to draw the line as what is merely chemistry and what crosses the invisible line into biology.  The famous "tobacco mosaic virus" behaves much like a virus inside a tobacco plant - but can be extracted and made into rather beautiful crystals that behave just like any other crystal - until you dissolve them in water and feed them to a tobacco plant - and then they seem to be alive again.  Similar problems exist with death.  Drawing the line at when a human dies has proven exceedingly difficult and controversial.  In the end, science has to say that there is no hard line - and just because the English language provides a sharp distinction - that's not necessarily how nature behaves.
 * Is is possible to give a precise definition of the two? - No.
 * Is it all just about electrical signals moving around, or is it something more? - No, the most primitive forms of life don't have neurons - and there is no electrical activity per-se...yet they are undoubtedly "alive".
 * Like, does Science acknowledge the existence of the soul ? - No science cannot find any reason to say that there is a soul. Hence Occam's razor says that we should simply ignore the possibility until/unless some actual evidence shows up.
 * With all the modern theories floating around, is it possible to write an equation of life? - Well, it wouldn't precisely be an "equation" - and as I've pointed out - it's not a bright line. But it's just like the stupid argument about whether Pluto is a planet or not.  "Planet" is just a word - it doesn't have any solid scientific essence beyond what we choose to embue it with.  So if we choose to define the word to exclude Pluto, then Pluto isn't a planet anymore.  Nothing changed about Pluto - our understanding of it didn't change because of that name change.   Similarly with "Life" - if we choose to say that virusses are not alive - then they aren't.  If we say that they are - then they are.   That doesn't affect anything other than the word we use when we talk about them.
 * Have we understood how life first came into existence, - Not conclusively. There are many theories surrounding 'abiogenesis'.  The most probable (and certainly plausible) idea is that fairly complex carbon compounds (what we judgementally call "organic molecules") can form spontaneously in the air/water/ground of early earth.  There are experiments that show that directly.  Then, these molecules will react with each other - pretty much at random - and complicated molecules will come about purely by chance.  If it is only a billion, billion, billion to one chance that one of those random molecules could spontaneously reproduce itself - then evolution can kick in and pretty soon after, we'd have recognisable life.   The math to figure out the probability of that exceedingly unlikely event is tough to work out because we don't yet know what the simplest possible self-reproducing molecule might need to be.  But because these reactions were occurring over trillions of cubic kilometers of water over a billion years - the odds can be exceedingly remote - and yet still add up to an almost certain chance of life appearing completely at random.
 * Have we...perhaps come anywhere near creating it? - Yes. There are at least two groups of scientists trying to do exactly that - and they are very close to success.  They have made molecules that can self-reproduce when enclosed in a very simple droplet of oily lipids - and I would lay good odds of them having an entirely artificial lifeform within 5 years.  Of course, that assumes that your definition of "life" has to include chemistry.  Computer scientists have long been making synthetic lifeforms within the computer that can do pretty much everything that "real world" life does...including evolving into higher forms.
 * Is death something like an infinite sleep, or is it something more, or perhaps less? - The evidence is only that the brain stops working. No different from switching off a computer.  How this must 'seem' to the person doing the dying is something of an unknown - but a gradual death seems that it might be a lot like falling asleep - a sudden one is just a sudden nothing.  You can't ask what THAT feels like because the thing that's doing the feeling stopped working.
 * I have heard theories like Super string theory and Combined Quantum Gravity (pardon me if i am wrong) claim to explain everything. - Yes, but at a very very low level of explanation. Certainly there is the possibility that one of these theories might come to have the potential to explain everything down at the lowest possible level.  But you would require an insane amount of time or computer power to go from a detailed description of how superstrings interact to get to the point where you could explain how a single DNA molecule does what it does.   The potential to explain everything might be there - but that's not enough.  To put it another way - you probably know all of the rules to the game of chess.  Can you tell me then whether white will always win if he plays without making any mistakes?   Well, theoretically - you have enough knowledge to answer that - but in practice, the number of possible games of chess exceeds the number of fundamental particles in the visible universe - so there is really no way to go from knowing all the rules to answering that kind of question.  However, if I ask the same question about TicTacToe (Noughts-and-Crosses for us Brits) - a knowledge of the rules is all you need to say that if both players play a perfect game, then it'll always end in a draw.  Well, superstring theory might MAYBE be able to tell us how something as simple as a hydrogen atom works in amazing detail - but it's still not going to answer the question of Life, The Universe And Everything.  (Unless it really is 42).
 * Does that include life and death? - No - because those are just two words and until we decide what we want them to MEAN - we can't apply science to them.
 * Are we any closer to solving that mystery of finding where we came from? - Yes. Every day, we get a little bit closer.  I would be surprised if we don't have a complete explanation in my lifetime (and I'm 54 years old).  The largest piece of the puzzle is that 'abiogenesis' step - how did the very first most primitive thing that we'd say was "alive" (because it could reproduce - and therefore evolve) come about from a bunch of "chemicals".  But "life" and "death" are really just words with poorly defined meanings.  If we came up with two new words "squibbobble" and "anti-squibobble" and defined rigorously the meaning of squibobble as something like "an object which is capable of evolving" - then there would be no ambiguity (well, perhaps with that exact definition there still is...but you see what I mean).  Sadly, people who are no longer capable of having children (eg women who are past menopause) would fall into the 'anti-squibobble' category - and just as with the definition of the word "planet", everyone would get very upset about it...even though it's "just a word".

SteveBaker (talk) 22:21, 9 April 2009 (UTC)


 * Have we come anywhere near creating it? If you include viruses as 'alive,' at least one has been made from scratch - kinda scary actually. --Bennybp (talk) 01:54, 10 April 2009 (UTC)


 * The first (and second) sentence says "A deadly virus has been made from scratch using standard laboratory equipment, an internet recipe and DNA freely available from mail-order companies", but if it's using pre-existing DNA, I'm not sure it's fair to say it was created from scratch. A Quest For Knowledge (talk) 10:38, 10 April 2009 (UTC)
 * No - the DNA is entirely synthetic. It came from companies who will take a list of A's, G's and T's in an email and for some amount of cash, send you back a bucket of DNA snippets that have that description.  They start from scratch with Amino acids - so this is truly synthetic.  They also inserted that DNA into an already functional organism - so they didn't have to make the other parts of the cell.  What is also "cheating" is that they used the DNA code from a "natural" lifeform - they didn't design it from scratch.  After a couple of generations, their "synthetic" virus would be utterly indistinguishable from the "natural" virus.  However, there are also scientists out there who are trying to build a lifeform that's not just constructed synthetically - but also designed from scratch and placed into a cell-like structure that's also built from scratch.  Such organisms would be entirely unlike anything else on the planet. SteveBaker (talk) 11:32, 10 April 2009 (UTC)


 * Oh, cool. Thanks! A Quest For Knowledge (talk) 13:09, 10 April 2009 (UTC)


 * Synthetic life may be of greater interest although sadly in a rather poor state Nil Einne (talk) 11:13, 10 April 2009 (UTC)

There are different concepts about life and death in different religions. Anyways for the definition of life visit I've heard there are two kinds of people: These who divide things into distinct categories, and those who don't. What would be the criteria for determining whether a potato is "dead" or "alive" when it is on a shelf in my kitchen? It arrives full of vitality, and eventually sprouts. If planted, it would produce roots and leaves and more potatoes. Seems to be alive,but if I remove the "eyes" when it arrives, surely that does not mean it is suddenly dead, any more than a steer is dead. If I boil it long enough, that would seem to make it dead. If it rots, that would also seem to make it dead, although full of bacteria. —Preceding unsigned comment added by 59.103.63.141 (talk) 03:57, 12 April 2009 (UTC)


 * Language is a human invention - the universe runs along quite happily without it. Unfortunately, we humans are so dependent on our language that we come to believe that it's defines things solidly in cases when it really doesn't.  Language is a purely artificial construct...words don't (by themselves) 'mean' anything without some external definition (such as in a dictionary or something).  But in the case of some words, there simply isn't a solid definition.  Certainly, in this case, we've come up with words: "alive" and "dead"...and..."lifeform" and "inanimate object" without there being any kind of solid, formal definition of those terms.  However, these words exist and are mostly used unambiguously. My dog is "alive", my great-grandfather is "dead", my dog is a "lifeform" and my pet rock is "inanimate" - nobody is likely to argue about that.  This leads most people to get the idea that there must, somehow, be a single defining thing that distinguishes these states.  In truth, there is no such 'bright line' - these words are vague, fuzzy things.  Someone who's heart has stopped yet is subsequently revived - or someone who's brain exhibits no "higher brain function" but who is still breathing unaided is in that fuzzy region.  Similarly, viruses and prions are in that grey area between lifeforms and inanimate objects.  Worse still, we have computer programs that can behave like lifeforms which are even harder to categorize.  These difficulties are only linguistic matters though.  Science is well on top of understanding all of the details of what's going on...there is no mystery in that sense...it's just that you can't say definitely whether all things are or are not alive.


 * However, despite that, this kind of issue where people cannot or will not grasp that most words are vague is the cause of many problems. Consider the Terri Schiavo case - where a woman remains for 15 years in a 'persistent vegetative state' while people argue through the courts (culminating in a presidential edict no less!) about whether she is in fact already dead - or should be allowed to die - or is alive and therefore cannot be allowed to become dead.  The truth is not that we had to decide whether she was alive or dead but that wee needed to recognize that those two words are so vague as to make it impossible to determine which word applied to her condition.  Sadly, the law demands hard and fast determinations to be made - and that's a ridiculous requirement when the terms used are ill-specified.


 * If, instead of "alive" and "dead"...and..."lifeform" and "inanimate object" we had more quantitative words, these confusions would largely evaporate. If there were a scale of aliveness and Schiavo could have been assessed as only (say) 4% alive - then the controversy about allowing her to become only 3% alive and then 'naturally' slip into 0% aliveness - then the situation would have been a lot different.


 * SteveBaker (talk) 05:54, 12 April 2009 (UTC)

The question of the meaning of souls in a materialistic world-view is examined by Douglas Hofstader in his recent book I am a Strange Loop; so it's not altogether true that science has nothing positive to say about souls. Hofstader is a materialist, though, so he's not arguing for any extrinsic, truly spiritual entity, but rather a large-scale information pattern encoded into one or more minds - which form part of living beings. Thus, answering the 'soul' question doesn't necessarily answer the 'life' question. AlexTiefling (talk) 14:40, 14 April 2009 (UTC)

Colorado Bug ID
Alright, I'm a resident of Colorado Springs who's slightly concerned about these weird beetles/roaches I've been seeing around. There's a trail not far from where I live that I frequent, and there's this large mound about a yard across, dotted with holes roughly one inch in diameter. I believe this to be their burrow or nest, as they consistently retreat into said holes as I approach. These insects are roughly an inch and a half long, and fast as sin. I have literally never seen one up close, as they constantly are buzzing and darting quickly away when I get near. I'm sorry I can't give more information, these critters are just fantastic at hiding, and lord knows I'm not going to go poking around that nest. Thanks! 128.198.32.24 (talk) 22:31, 9 April 2009 (UTC)


 * I've never heard of a bug that fits that description -- seems to mix attributes of roaches, ants, and mice. Looie496 (talk) 23:02, 9 April 2009 (UTC)


 * Social insects in large colonies (about a yard or meter across) does somewhat limit the possibilities. Could they be termites ?  What color are they ?  Do they fly ?  Do they have long antennae ? StuRat (talk) 00:32, 10 April 2009 (UTC)


 * Wrap a piece of duct tape around a small box sticky side up. Leave that near one of the holes. (Most bugs like sugar, so you might want to sprinkle a bit on your trap.  Walk away for a while.  If you managed to trap one of the critters take a picture and we might be able to help you identify them. Bring something to dispose of your trap in after you used it.  You don't want to leave it as litter. 76.97.245.5 (talk) 07:12, 10 April 2009 (UTC)\

UPDATE: OP here. After consulting with some friends, I have discovered that these insects are most likely a breed of native Coloradoan Cicada. I took a listen to the recording on a cicada cry on the wiki page, and I'm quite sure we have a match! Thanks for your help, folks! These are some creepy little bugs! 75.148.127.194 (talk) 01:29, 11 April 2009 (UTC)

StuRat (talk) 14:43, 14 April 2009 (UTC)

Noisy chalk holders
Why does the squeaking and skipping of chalk get worse with chalk holders (any that I've ever used, at least)? 124.154.253.25 (talk) 23:13, 9 April 2009 (UTC)


 * This is pure speculation - but the cause of the squeak is likely related to resonance in the chalk - and when you hold it in your fingers, that soft flesh is damping out the vibrations. The chalk holder may perhaps change the resonant frequency and perhaps make it worse. SteveBaker (talk) 23:30, 9 April 2009 (UTC)
 * Also maybe related is a change in the angle of the chalk on the board and how hard you are pressing. With the right combination of angle, pressure, and grip tightness, you can get enough resonance that the chalk skips off the board entirely and draws a clean dotted line. DMacks (talk) 06:50, 10 April 2009 (UTC)
 * Unfortunately I've never found an appropriate angle/pressure that will cancel out/dampen the vibration sufficiently with the holder on, unless I press so hard as to break the chalk (though it might still squeak while doing so) or hold it right on the tip, which usually nulls the benefit of using the holder in the first place. A change in the resonant frequency makes sense though, now that I think of it. The chalk is slightly longer and quite a bit fatter with the holder, and if the resonant frequency were lowered enough by the increase in size it might vibrate off the drawing surface. Normal chalk usually squeaks when you hold it too far up too; I would guess near the point of a resonance overtone and/or far enough away that the fingers aren't able to absorb so much of the vibration. Thanks for the responses! 124.154.253.25 (talk) 08:37, 10 April 2009 (UTC)
 * Cool! I think that pretty much clinches it then.  Is it possible that you could install something soft between the chalk and the holder?  I'm thinking of a thin strip of foam rubber - or perhaps even a strip of cloth might be enough...that might dampen out the vibration sufficiently to prevent it from building up into a squeak.  If the chalk holder itself is resonating (which seems unlikely) then perhaps epoxy-gluing a chunk of lead to it would change the frequency enough to take it out of the range of human hearing?  However, if the chalk squeaks when you hold it too far up - then that says that it's the chalk itself that's resonating - so messing with the holder's resonant frequency may not help at all.  Failing, those things...white boards and marker pens! SteveBaker (talk) 10:06, 10 April 2009 (UTC)