Wikipedia:Reference desk/Archives/Science/2011 January 8

= January 8 =

Gravity/Conciousness
It has been suggested that the incredible weakness of gravity compared with the other forces is because gravity is the only force which mainly resides in the other dimensions postulated by string theory.Is it conceivable that thought/afterlife/conciousness act similarly as gravity waves, like thought waves, have yet to be detected.

John Cowell.00:28, 8 January 2011 (UTC)= —Preceding unsigned comment added by 118.208.93.193 (talk)
 * Certainly it's conceivable: you've just conceived it. Whether it has any merit as a scientific theory is another matter. I am not aware of any evidence that thought, whatever it might be, has any properties in common with any of the fundamental forces of nature or the waves that mediate them. --ColinFine (talk) 00:54, 8 January 2011 (UTC)
 * Roger Penrose believes that there is an important relationship between consciousness and quantum gravity. The idea strikes me as kind of silly, but it has received a certain amount of attention, or perhaps notoriety is a better word. Looie496 (talk) 01:04, 8 January 2011 (UTC)
 * Yes, but Penrose does not claim that he has actual evidence for that hunch. (His metaphysical ideas are controversial, whereas his actual science is acknowledged by everyone to be solid -- and he seems to be perfectly aware of and candid about which is which). –Henning Makholm (talk) 03:00, 8 January 2011 (UTC)
 * It strikes me that the burden of proof is that on those who would claim that consciousness is anything more than something materialistic. The brain seems to be a fairly modular thing — there's a strict movement "upwards towards consciousness" (metaphorically, of course) moving from less-to-more complicated brains (lizards, dogs, dolphins, chimps, humans, etc.). This strongly seems to suggest that consciousness is "simply" a very complicated function of a very complicated set of neural wirings. Why one would want to introduce extra dimensions into the equation (other than the desire to not simply be a blot of matter, doomed for a finite amount of time) seems, from a scientific standpoint, fairly unclear. It doesn't mean it isn't possible. But does a lizard have the same physical hardware that you are postulating? Does a dog? Does a housefly? Does an amoeba? Does a virus? And if not, why would humans have it, and no others? Where does it start, and where would it stop? It just doesn't really seem, a priori, to be a very compelling theory, at least to me. It seems far more likely that what we call consciousness is just a measure of specialized computational organs/circuits/what-have-you within the forebrain brain. Circuits we do not at all fully understand, to be sure, but I think we're starting to get close to a general model of things, and it doesn't include anything like you're suggesting. --Mr.98 (talk) 03:43, 8 January 2011 (UTC)


 * I'm reading the question as discussing gravity just as an initial example of something the OP has heard may also exist "in other dimensions" according to "string theory".
 * The actual question is then: could consciousness exist in other spatial dimensions, and if so could our sense of consciousness in this 3-space be in some meaningful way "connected" to corresponding consciousnesses in other sets of spatial dimensions?
 * If I'm interpreting that correctly, then I'd have to say "maybe". I don't know enough about strings and Mbranes and whatever else to know whether in the various theories about them, it is possible for an elementary particle in our 3-space to be a manifestation of a multidimensional vibration that also manifests as "corresponding" elementary particles in other N-spaces.  If so, then perhaps the particles making up our brains are mapped onto various other "brains" (including whatever higher-than-3-dimensional corresponding structures might be called).  Maybe the complexity of how those vibrations/string/particles are organized in each of those other spaces also produces a consciousness that corresponds to our consciousness in this world.
 * That would be kind of spooky, wouldn't it be? :) I don't have an answer as to how likely anything like that might be, though – and, remember, "string theory" is still all just a mathematical framework with no empirical support whatsoever or any likelihood of there being any anytime soon, either, afaik.  So even if this kind of thing were supported by theory, there would still be little reason to believe it is anything like that in Reality.  WikiDao    &#9775;  04:38, 8 January 2011 (UTC)


 * The OP may be interested in Leibniz's Monad theory. Like Penrose, Leibniz had some interesting thoughts regarding consciousness and physics. Also like Penrose, Leibniz's scientific contributions are well respected. In the Monadology he hints that perception and consciousness may be tied to the fundamental units of matter. Or something. I don't think many people subscribe to theory of Monads these days. SemanticMantis (talk) 05:50, 8 January 2011 (UTC)


 * It seems to me that the fact that consciousness evolved is a pretty strong argument against the idea that it harnesses any sort of subtle as-of-yet unknown physics. Much of modern physics could have been very useful to biological entities (e.g. lasers, radio waves, ...) but organisms "naturally" using such physics completely failed to evolve anywhere in the biosphere. Why should consciousness be an exception? 83.134.178.145 (talk) 10:13, 8 January 2011 (UTC)
 * Still, there is something for science to explain here which, so far, it has not been able to do. There is no workable scientific description of the phenomenon of self-awareness.  Everybody is aware of this because one is directly experiencing it - the division of the world between me and not-me and the sensation of being inside looking out on the rest of the universe.  We believe that everyone else has this sensation only because we have it ourselves: there is no objective test to detect or measure it.  If I claim my computer is self-aware there is no test to prove me wrong.  If I claim that my mother is not self-aware, what test could be administered to falsify the claim?  One can ask the subject if they are self-aware, but to any question I could, at least in principle, program my computer to give the same answer as given by my mother.  Someone famous said this was the last great unanswered question of science.  Given that we cannot even detect it, it is a little premature to ask how many dimensions it exists in.  Sp in ni  ng  Spark  15:14, 8 January 2011 (UTC)
 * Presumably your mother could pass a mirror test. While by no means air-tight, many professionals would use this as evidence for self-awareness. SemanticMantis (talk) 15:46, 8 January 2011 (UTC)
 * She probably could, but then so could my computer with the help of a clever programmer so a positive result would not be determinant. Failure to pass the test likewise does not prove beyond doubt lack of consciousness.  Sp in ni  ng  Spark  16:18, 8 January 2011 (UTC)
 * I suspect that most cognitive scientists would see this partially as a problem of definition. We treat consciousness and self-awareness as a "I know it when I see it" sort of affair. We have a very hard time articulating what we think it means in measurable terms. I suspect what we see as one phenomena is really a bundle of things running on different "circuits" in the brain. I still find, though, that there is little to make one think that a non-materialist, non-emergent solution makes any sense. The brain is one complicated piece of hardware — that's true even of far more "lesser" brains than human ones. It strikes me as essentially premature and illogical to assume that we should begin by appealing to things outside of the brain to understand it. There's plenty there that we still need to understand before we conclude that a wholly biological �answer is insufficient.
 * Incidentally, the computer answer doesn't disprove the original test. The only reason the computer can do it is because a self-aware being made it be able to do so. So there is self-awareness in that system — it comes from the fact that a self-aware being said, "hey, here's how we fool this test." What would be more interesting is if a computer system that was not programmed to do that specifically somehow developed that ability. That would be more akin to the biological analog. ---Mr.98 (talk) 16:52, 8 January 2011 (UTC)

Brain
Will putting things in your brain kill you? And what do FFI prions taste like? —Preceding unsigned comment added by 203.96.12.131 (talk) 04:13, 8 January 2011 (UTC)


 * (1) Not necessarily, but it will void your warranty. (2) Chicken. –Henning Makholm (talk) 04:38, 8 January 2011 (UTC)
 * (1) ... as a side note, despite many attempts, I have never been able to contact customer service; so I suspect the warranty is ineffectual anyway --Senra (Talk) 18:14, 8 January 2011 (UTC)


 * Depends. A brain surgeon could probably put something in there without doing too much damage. This is occasionally done. Microchips and such. See Neural implant.
 * If you're just talking about shoving something in there, then sure, there's a serious danger. But even so, some people survive it. See Phineas Gage!
 * Finally, I doubt you'd ever get enough prions together in one place to actually be able to taste them. APL (talk) 05:01, 8 January 2011 (UTC)
 * Putting in a couple of working neurons might help some people. Prions taste of nothing but they smell of troll. Caesar&#39;s Daddy (talk) 07:42, 8 January 2011 (UTC)
 * Reading Wikipedia puts thoughts in my brain. It hasn't killed me yet. Gandalf61 (talk) 07:56, 8 January 2011 (UTC)

At the risk of giving medical advice, please don't put physical objects into your brain. It's much more likely than not to harm you, and even small brain lesions can in fact lead to death depending on their location. Prions don't likely have any discernible flavor. 71.198.176.22 (talk) 16:30, 8 January 2011 (UTC)


 * It's very easy to put something in the brain without killing someone: see lobotomy. That being said, it's fairly difficult to put something in the brain without appreciably damaging it, and probably requires a medical degree to do so on a regular basis (it literally is brain surgery, after all). Buddy431 (talk) 22:50, 8 January 2011 (UTC)

Motor
First motor invented or generator invented becoz I heared the motor was the first am I right? — Preceding unsigned comment added by Kanniyappan (talk • contribs) 11:14, 8 January 2011 (UTC)


 * Yes. Dynamo says "The first electric generator was invented by Michael Faraday in 1831". It then apparently contradicts itself by mentioning Jedlik's dynamo, 1827. Electric_motor says Faraday invented a mercury motor (which does no useful work) in 1821. I don't know if he was the first to make such a thing, and technically every motor can be used in reverse as a generator, but pushing the wire around in circles in an attempt to generate current sounds difficult, so assuming nobody made any higher-tech motor before Jedlik's dynamo, the motor came first. 213.122.7.185 (talk) 14:53, 8 January 2011 (UTC)
 * A partisan advocate of Jedlik introduced many dubious claims based on sources in Hungarian. 19th century histories of motors and generators (in English) only credited Jedlik with some dynamo improvements much, much later than the claims in the Wikipedia articles about Jedlik, motors, and dynamos. We need someone able to read Hungarian to clarify what the sources actually say. Edison (talk) 20:30, 8 January 2011 (UTC)
 * If you consider a steam engine to be a motor, then they go all the way back to Hero's engine. StuRat (talk) 14:55, 8 January 2011 (UTC)

Cosmology
I recently heard of an idea: an explosion so massive, that it sends shockwaves through space-time. At subluminal speeds, an observer should be able to see a wave front of Lorentz and time contraction, followed by dilation of both kinds. Is this a plausible idea? --Plasmic Physics (talk) 11:37, 8 January 2011 (UTC)
 * Not exactly, but gravitational waves come close. The largest difference from your description is that gravitational waves are supposed to propagate at lightspeed, and that they cannot (as a matter of GR mathemathics) be exactly spherically symmetric, so they wouldn't be generated by a symmetric explosion however massive. –Henning Makholm (talk) 12:51, 8 January 2011 (UTC)

What should create notable gravitational waves, what should the intensity be proportional to? --Plasmic Physics (talk) 22:24, 8 January 2011 (UTC)

Faking carbon/radioactive decay
This is a bit of a complicated question relating to carbon dating and radiometric dating.

Carbon dating is useful for finding the age of relatively recent fossils. The carbon-14 begins to decay, and around 5700 years or so, it's half replaced with nitrogen-14. Every 5700 years (the "half-life" of carbon-14), half the remainder decays. We can measure around how old the fossil is by comparing the amount of carbon-14 to nitrogen-14.

What I was curious about is, would someone be actually able to change the amount of either carbon-14 or nitrogen-14 in the fossil? Is such a process possible?

Of course, carbon dating only works to about 100,000 years ago. For older fossils or actual rocks, you use radiometric dating (as I think it's called). Let's say this mineral is full of uranium-235. After about 700 million years, it's half replaced with lead-207. So 700mya is the half-life of uranium-235. After another 700mya, another half of the uranium-235 has been replaced with the lead-207, and so on. Would it be possible to remove or add bits of either the uranium-235 or the lead-207, like I suggested with the carbon-14 and nitrogen-14?

Please note, I'm not suggesting to actually fake fossils and minerals in this way. That would be bad...but is it possible? Crimsonraptor &#124; (Contact me) Dumpster dive if you must 15:00, 8 January 2011 (UTC)


 * All forms of radiometric dating (of which carbon-14 and uranium series dating are two of several examples) are subject to errors from contamination, sediment mixing in fossils, and other sources of incidental, accidental, and systematic errors. That is why most radiochemists prefer to date from as many sources of information as possible to cross-check. Intentional contamination seems fairly difficult to me, however. If you're a paleontologist who wanted to pass off a fossil as older or younger than its radiometric age, you might be able to guess about which part of the fossil to contaminate, but I'm not sure how good such a guess could be, or whether such tampering wouldn't be obvious or at least make the radiochemist sample from a different part of the fossil.  Other less sophisticated forms of scientific fraud (misreporting measurements, for example) are much more common. 71.198.176.22 (talk) 15:48, 8 January 2011 (UTC)


 * You would need to replace a portion of the fossil with something of a different age. If you knew in advance the exact location where the sample would be taken, this could be done (although making it look right would be tricky).  Otherwise, you might have to replace the entire fossil. StuRat (talk) 15:51, 8 January 2011 (UTC)
 * OK, so you'd have to change the actual material itself, not the stuff in the material? Crimsonraptor &#124; (Contact me) Dumpster dive if you must 15:55, 8 January 2011 (UTC)
 * Yes, because the fossil and surrounding material has to be removed as a sample and pulverized to extract the daughter isotopes of interest. The sort of tampering you're contemplating here might very well be more difficult than fabricating an entire fossil from scratch (which has happened at least a few times in the history of scientific frauds. In the art world this kind of deception would be much easier, because owners of valuable art can restrict chemists from sampling all but certain portions of the work in order to prevent it from being disturbed in a detectable fashion.  That allows forgers more leeway.) 71.198.176.22 (talk) 16:19, 8 January 2011 (UTC)


 * Most radiometric dating methods would not be able to date the fossil directly anyway. The sequence of rocks containing the fossils can be dated by working out the age of lavas or ash layers interbedded with the sedimentary rock e.g.. It would be simpler just to claim a fossil find from the wrong part of the sequence, but no-one would accept that unless other examples were forthcoming. Mikenorton (talk) 16:01, 8 January 2011 (UTC)
 * There also is a strong difference between 14C-dating and most other dating methods. 14C dates organic material. It depends on the fact that 14C is created at a (fairly) fixed rate in the atmosphere, and hence is at a fairly constant level in the atmosphere. Living things are in good equilibrium with the atmosphere. In other words, we know reasonably well what percentage of carbon in living things is 14C. Once something dies, it essentially stops exchanging carbon with the environment. 14C decays. The daughter element, 14N, typically escapes. We determine the age of the object by looking how the 12C/14C ratio has changed (by decay of 14C), without ever looking at the daughter element. Other radiometric techniques work differently. If you look at e.g. K–Ar dating, we do not know the initial amount of 40K. We do know, however, that the daughter element, 40Ar, is a gas, and will escape from molten magma, but not from crystallised rock. So we start with an unknown amount of 40K and zero 40Ar. For dating, we assume that all 40Ar we find is the result of the decay of 40K, and we can hence determine the age (of the solidification event) from the ratio of 40Ar to 40K. The nice thing about this is that we can repeat the experiment with different samples with different initial 40K. If the samples are the same age, and not contaminated somehow, they will all have different absolute amounts of 40Ar an 40K, but all the same ratio of them. In a diagram, the different samples all fall onto the same straight line. This property allows us to detect contamination and problems, or, in the other case, to strongly confirm the dates.--Stephan Schulz (talk) 23:56, 8 January 2011 (UTC)


 * It seems to me that it ought to be possible, although I don't know anything specific. It seems to me that by subjecting the material to a flux of photons or other subatomic particles with the right properties, it would be possible to make the 14C decay more rapidly than it would otherwise.  This is definitely possible with uranium 235 -- it's the principle underlying nuclear energy generation.  It would, however, very likely leave behind substantial evidence of the manipulation. Looie496 (talk) 18:52, 9 January 2011 (UTC)

Dedendum circles
"dedendum circle diameter must be less than base circle diameter then the part of profile is not involute towards lower side of base circle." is this statement right for interference of involute profiles.are not the dedendum circles same as base circle.please help. —Preceding unsigned comment added by 59.93.129.167 (talk) 15:59, 8 January 2011 (UTC)


 * Can you clarify your question? Our article List_of_gear_nomenclature may help you out. It only explicitly defines dedendum angle, though the graphic for addendum shows a dedendum radius. The base circle radius is not the same as the dedendum radius. The article seems to indicate that the base circle radius plus the dedendum radius would give the pitch circle, but I may be misinterpreting. SemanticMantis (talk) 16:56, 8 January 2011 (UTC)

SnCl2-Sn(OH)Cl vs. SbCl3-SbOCl conversion
At what pH do these conversions take place? I have a solution with a pH of 1.5 and there is a white precipitate that must be either of these. --Chemicalinterest (talk) 18:33, 8 January 2011 (UTC)
 * The exact pH will depend on the chloride concentration. pH 1.5 seems quite acid for either one, unless you're right out of chloride in the solution, but the antimony will come out before the tin does, that's for sure. Physchim62 (talk) 02:28, 9 January 2011 (UTC)
 * Regardless of the pH, this is what I got. --98.221.179.18 (talk) 13:00, 9 January 2011 (UTC)

Dioxin in Germany
How and why did the Polychlorinated_dibenzodioxins contaminated food in Germany recently? Quest09 (talk) 19:13, 8 January 2011 (UTC)
 * A news article says "tainted fatty acids" used to make animal feed are suspected. Edison (talk) 20:26, 8 January 2011 (UTC)
 * yes, but why would someone taint animal feed with dioxin? If you feed hormones to a cow or chicken you make it fatter, but there is no advantage in mixing dioxin on purpose. So, why did it happen, where did it come from? Quest09 (talk) 20:40, 8 January 2011 (UTC)
 * It seems unlikely anyone purposely tained the animal feed (i.e. with the intention of adding dioxins) or at least there's no indication I've seen of that being the case. Various sources  suggest the fatty acids were intended for industrial (not industrial food!) use only but were mixed with the fatty acids intended for animal feed. Whether this was accidentally or not doesn't seem clear but it's suggested the company knew about the high level of dioxins for a long while . This doesn't explicitly answer why the fatty acids were contaminated but the first source (provided by Edison) says it's not uncommon. Nil Einne (talk) 21:18, 8 January 2011 (UTC)


 * It may have been like the antifreeze-in-wine incident of the past - it made someone money. The mineral oil was probably a lot cheaper than food-grade oil. 92.15.7.205 (talk) 21:35, 8 January 2011 (UTC)

I am a german. The Dioxin (probably TCDD) came from fat for industrial uses, just produced by heating it up. Nobody intentionally, or even accidentally, put a TCDD crystal in, but fats were heated up, dioxin produced, and the fats were only to be used for industrial purposes (e.g. manufacturing motor oil). But somehow the fat company sold it to a company called Harles&Jentzsch, which produces ready-to-feed food for chicken and pigs. Then Galloanserae ate this food, and because the dioxin is not biodegradable, it landed in amniote eggs, and meat. Reportedly, some private laboratory knew about a too high dioxin value from the 19th of March (!) but Harles&Jentzsch says that they only knew from the 27th of December onwards. — Preceding unsigned comment added by Eu-151 (talk • contribs) 17:40, 9 January 2011 (UTC)
 * How would fat, made of carbon, hydrogen and oxygen, gain the chlorine needed to make dioxin or PCB just by being "heated up"? I could understand if PCB contaminated oil were used in a heat exchanger, and some of it leaked from its tubing into the fat being heated. That sort of contamination has happened in the past in other countries. Edison (talk) 21:02, 9 January 2011 (UTC)

2D holographic display
In some sci fi media like anime or video games like dead space (video game) they have 2D holographic displays like this http://cdn.themis-media.com/media/global/images/galleries/display/55/55099.jpg is there any specific name for this kind of technology? Is there any real world tech working on this? All the articles on wikipedia just deal with 3D volumetric displays not 2D holograms. ScienceApe (talk) 20:04, 8 January 2011 (UTC)
 * You mean a 2d image projected out into thin air? I don't know if there is a general name for them. A company named Heliodisplay makes them. (They spray a thin sheet of mist into the air then project onto that.)  But they're mostly just gimmick. APL (talk) 21:56, 8 January 2011 (UTC)