Wikipedia:Reference desk/Archives/Science/2008 July 5

= July 5 =

Houdini exhumation
I followed the story of the proposal to exhume Houdini's remains. Some of his relatives wish to examine his remains to confirm whether or not he was the victim of arsenic poisoning, while others object to the exhumation. The latest information I can find dates from March, 2007. Joseph Tacopina represented the pro-exhumation faction then, but I would like to know who prevailed. Does anyone have current status on this case?Avid Djinn (talk) 00:08, 5 July 2008 (UTC)


 * Not exhumed as of 2008-03-04 according to:




 * -- Jeandré, 2008-07-05t18:26z

Future Indian Ocean Earthquake
Hi. Will there be another possible Indian Ocean Earthquake like the 2004 Indian Ocean Earthquake in the future? When will it happen again? What will be the possible magnitude of another future Indian Ocean earthquake? Sonic99 (talk) 00:52, 5 July 2008 (UTC)


 * It's not known. Earthquake prediction is poor. PrimeHunter (talk) 01:10, 5 July 2008 (UTC)


 * Hello again there Sonic, take a look here for some insight. ;-) -hydnjo talk 01:12, 5 July 2008 (UTC)


 * The answer to the first question is yes. There will be another very large earthquake on that fault eventually.  Whether it will be tomorrow, next year, next decade, or 5000 years from now is largely impossible to predict.  Dragons flight (talk) 01:45, 5 July 2008 (UTC)


 * According to Nature (journal), the recent earthquakes did not sufficiently release the accumulated fault strain and there is still the possibility of a magnitude 9.0 quake. The fault ruptures every 200-230 years and there is a 200-km zone that has not ruptured since 1797, so do the math.
 * Furthermore, it now appears that the active fault extends northward along the coast of Burma up to the coast of Bangladesh, and large quakes there would produce devastating tsunamis in the Bay of Bengal.
 * That said, the comments above about trying to predict exactly when an earthquake will strike are quite valid. (Although I did just read something interesting about using increased neutron flux for short-term prediction ). Franamax (talk) 22:59, 5 July 2008 (UTC)

Antarcticine
can anyone tell me more about this glycoprotein in terms of anti-aging? I have googled it but cannot find a suitable answerSwinstarr (talk) 02:46, 5 July 2008 (UTC)


 * There's a good bit of information in this article. Someguy1221 (talk) 09:34, 5 July 2008 (UTC)

Metrication in Greece
According to an 1866 report in the US House of Representatives, "Greece has introduced [the metric system] with some modifications." - I'm wondering what exactly these modifications are. It'd also be interesting in general to have more information about the history of metrication in places other than France and English-speaking countries. --Random832 (contribs) 07:33, 5 July 2008 (UTC)


 * For Greece, see Konstantinos Nikolantonakis' "Weights and measures: the Greek efforts to integrate the metric system" from section 5.1. For Italy, Spain, Portugal, and the Netherlands see the abstracts and PDFs at the 2nd International Conference of the European Society for the History of Science, Symposium R-8 pages. -- Jeandré, 2008-07-05t18:11z

Spin
Do electrons actually spin?? where does the intrinsic angular momentum value come from? —Preceding unsigned comment added by 116.68.73.39 (talk) 07:58, 5 July 2008 (UTC)


 * No one knows. Their electromagnetic properties (charge, magnetic dipole moment, conservation of angular momentum during particle interactions, etc.) exhibit behaviors similar to what a spinning macroscopic object with a non-zero charge distribution would produce, which is I believe why that characteristic is called "spin".  --Prestidigitator (talk) 08:46, 5 July 2008 (UTC)


 * Overview of spin might be of interest. Jdrewitt (talk) 11:13, 5 July 2008 (UTC)


 * Some hold the view that the 'spin' is not in any way equivalent to a rotation, but is in fact comparable to a chirality of the electron - the two spins being equivalent to 'left' and 'right handed versions' of the particle.87.102.86.73 (talk) 12:35, 5 July 2008 (UTC)


 * Electrons have zero size but non-zero angular momentum. This is weird. Make your own mind up about what to call it. "Spin" seemed like a good word at the time. -- Tim Starling (talk) 13:35, 5 July 2008 (UTC)


 * Then how/why is the Classical_electron_radius defined? Jdrewitt (talk) 15:43, 5 July 2008 (UTC)


 * It answers how and why in that article you just linked to. — DanielLC 15:53, 5 July 2008 (UTC)


 * Well I wouldn't say it answers exactly how and why (at least why re isn't defined) but then that's quantum mechanics for you! Jdrewitt (talk) 15:58, 5 July 2008 (UTC)


 * Classical electron radius is a useful characteristic length for the extent of the electric field around an electron. However, the mass and charge of the electron is concentrated at a point at the centre. Models for the electron involving a distribution of charge have been rigorously disproven. Under classical electrostatic theory, this leads to the rather embarrassing result that an electron has infinite electric potential energy. Solving this problem was one of the early challenges for quantum electrodynamics. -- Tim Starling (talk) 00:17, 6 July 2008 (UTC)

Quantum numbers
I've learnt about quantum numbers describing electrons, but are there quantum numbers for other particles(fermions, in particular)? If they have spin, there must be other quantum numbers too. If so, how are they different from those of the electrons? —Preceding unsigned comment added by 116.68.73.39 (talk) 08:02, 5 July 2008 (UTC)


 * The quantum numbers you refer to come about from the wave equation for an electron "orbiting" the nucleus of an atom. There will be quantum numbers describing any particle in any kind of potential, but there may not be the same number of them and they may not take on the same values.  Some quantum numbers (such as spin) do seem to be intrinsic to the particle though.  The quantum number and spin (physics) articles may be a good place to start learning.  --Prestidigitator (talk) 08:59, 5 July 2008 (UTC)

Can crouching, breathing deeply, rising quickly lead to fainting?
Is this an old wives' (or young high schoolers' :-) tale or not? Someone at school said if you bend your knees in a crouch, take bout 15-20 deep breaths, then try to stand up quickly, you pass out. Do you?

Either way, exactly what problems can this cause? I was tempted to try taking 20 deep breaths like that, then lay down from that position one night but even that I was too scared to do, just in case. Would that have caused a problem.

And, in case, there is anyone else reading this - please be like me, don't try it at home.209.244.187.155 (talk) 15:11, 5 July 2008 (UTC)


 * Finally fixed my edit - sorry for the apparent incompetence :-)
 * Anyway, I would think it might, by inhaling and exhaling deeply 10-20 times, you relax the muscles enough that they become too weak to supprt you right away, but aside from fainting I'm not sure there would be any other problem, unless you hit your head on something.
 * Still, I agree - NEVER do that.Somebody or his brother (talk) 15:14, 5 July 2008 (UTC)


 * Hi. Have you read our article on brownouts? Thanks. ~ A H  1 (TCU) 16:10, 5 July 2008 (UTC)
 * I think this is similar to the choking game. --Mark PEA (talk) 17:26, 5 July 2008 (UTC)


 * This sounds like nothing to be worried about, but you might find Orthostatic hypotension and Hyperventilation interesting reads. Even if this did cause you to black out, I'd be more concerned about hitting your head when you collapsed than from hypoxic brain damage. --Shaggorama (talk) 00:40, 6 July 2008 (UTC)

I tried it inbetween the corner of two walls and a cushion. I crouched on the balls of my feet and bent to where I could keep my balance with my fingertips on the cushion and took 20 deep breaths, each of 2-1/2 to 3 seconds inhaling and 2-1/2 to 3 seconds exhaling. I felt a little faint at times breathing and when I was done I stood up quickly and felt very faint, particularly for the first couple of seconds after standing, but I didn't fall or feel in danger of falling. I came directly here to type this and I still don't feel entirely un-faint. I'm 25, male, and in average-good shape. -LambaJan (talk) 17:13, 6 July 2008 (UTC)


 * wow...uh, thanks for taking one for the team, I guess. Be safe. --Shaggorama (talk) 04:19, 7 July 2008 (UTC)


 * I doubt the breathing has all that much to do with it in terms of oxygen intake -- as Shaggorama said, it's probably just a form of head rush. Speaking as a non-doctor, I'd assume that the deep breathing serves to lower your heart rate and generally calms you down, which also lowers your blood pressure. When you get up quickly, hey, it's orthostatic hypotension time, baby! A comparable thing has happened to me once or twice. In one memorable instance, I was expecting a really important phone call and took a nap, and when the phone rang, I woke up and immediately dashed out of bed. I remember taking a couple of steps and heading for the phone, and then the next thing I knew, I came to on the floor feeling kind of nauseous and with the phone on my hand, evidently immediately after passing out, as the caller didn't even realize that anything out of the ordinary had happened. (I don't think I'm particularly susceptible to it, really, but I've certainly learned to not just spring on my feet as quickly as I can when I wake up.) -- Captain Disdain (talk) 12:02, 7 July 2008 (UTC)

electromagnetic force uses photons as a mediator
is this saying that when I play with magnets there are photons being exchanged?

How about when I play with built-up charges in a Van de Graaff generator? —Preceding unsigned comment added by 71.147.33.238 (talk) 16:15, 5 July 2008 (UTC)
 * From my shaky understanding:
 * When you play with magnets, you are moving a magnetic field, no photons are being exchanged per se. If your magnet causes electrons to move in a conductor, the moving electric charges will cause an electromagnetic field to emanate, this is propagated by photons.
 * Similarly, with a VdG generator, you are creating an electrostatic field, again no photons involved. When you ground the generator though, lets say through a spark gap, you can hear it on a radio - again, moving electric charges generate an electromagnetic field which propagates through space by means of photons which eventually strike the radio antenna and cause electric charges to move there.
 * Don't know if that makes it clearer and I welcome any other views on this. Franamax (talk) 20:12, 6 July 2008 (UTC)


 * The current standard-advanced-physics view is that the electromagnetic force (that is both electricity and magnetism) is mediated by virtual photons. That is, when two particles interact via the electromagnetic force (e.g attract/repel each other) a virtual photon is traded between them, and it is this virtual photon which carries the energy and momentum between the two particles. Feynman diagrams are one way to visualize the process. Virtual photons are different from regular photons in that they are (literally) living on borrowed time, and can't be detected directly. In some sense they're a convenient fiction, but one which works remarkably well (that is, the world acts like it should if virtual photons existed). I'd encourage anyone interested in the topic to read QED: The Strange Theory of Light and Matter by Richard Feynman. It is a remarkable well written and understandable book. -- 128.104.112.147 (talk) 20:09, 10 July 2008 (UTC)

Why do s-orbitals always take part in hybridistion?
In hybridisation of atomic orbitals, why do s-orbitals always take part?Ashudeep2singh (talk) 16:54, 5 July 2008 (UTC)
 * Hybridization leads to stabilization: if s overlaps p, the s electrons go down in energy (see LCAO). But more philosophically, why not? No seriously...the s orbital is spherically symmetric, so no matter what direction you look (i.e., the directional orbitals (p, d, etc) with which you might hybridize), there is electron-density there in the s. An s orbital can constructively overlap with p, d, etc because it is in the same place, and electron delocalization is a good thing. DMacks (talk) 18:52, 5 July 2008 (UTC)
 * To expand on that - when constructing a bonding orbital, it is impossible to ignore the s orbitals because they are spherically symmetrical.. you could imagine a p3 orbital instead of a sp3 orbital - but anything that bonds to that p3 orbital would probably have significnt orbital overlap with the relevent s orbital as well..
 * However in construction of say sp2 orbital you will note that the other orbital that remains is a single p orbital.. in this sense this gives an example of a hybridised set of orbitals in which one orbital does not contain s 87.102.86.73 (talk) 10:09, 6 July 2008 (UTC)

Platypus evolution
Regarding the platypus, according to this, http://en.wikipedia.org/wiki/Platypus#Evolution it seems the platypus contains some genes that are more similar to birds. This I found unusual because mammals evolved from Synapsids, and not birds, which evolved from true reptiles. So basically I'm asking how do you explain this similarity with birds, when mammals did not evolve from birds?

I would also like to know what kind of sex chromosomes reptiles have. The article said, "the sex chromosomes of the Platypus are more similar to the ZZ/ZW sex chromosomes found in birds.", well if amphibians and reptiles don't have those chromosomes, then that would raise a lot of questions about what platypus evolved from. The article in Nature said that the platypus shares two genes found previously only in birds, amphibians and fish. I'm not sure if they are referring to the sex chromosome though. But even if they are, they are insinuating that reptiles don't have those sex chromosomes. Well that's strange because birds evolved from true reptiles and not synapsids which probably did have those sex chromosomes. If reptiles don't have those chromosomes, well it raises a lot of questions. ScienceApe (talk) 17:51, 5 July 2008 (UTC)


 * Well, I think the point is that the platypus diverged from the rest of mammals very early on. My guess is that the genes in question that are no longer found in any other mammals probably have to do with the egg laying aspects, etc. To my mind the issue is not "what the platypus evolved from" but "what did the very early mammal genome look like?" It seems not unreasonable to me that it could contain all sorts of elements in it that were quickly filtered out (through a number of possible issues, like founder's effect) but the monotremes seem to have skipped out on the big filter. But this is just speculation. --98.217.8.46 (talk) 19:15, 5 July 2008 (UTC)


 * That doesn't really address the concerns I mentioned. In particular the sex chromosomes reptiles have. ScienceApe (talk) 23:41, 5 July 2008 (UTC)


 * I don't know much about sex chromosomes and evolutionary lineages but according to ZW sex-determination system, it's found in birds, fish and insects. It also mentions "Chromosomes in the ZW region in birds are autosomal in mammals, and vice-versa; therefore, it is theorized that the ZW and XY couples come from different chromosomes of the common ancestor. A paper published in 2004 (Frank Grützner et al, Nature; doi:10.1038/nature03021) suggests that the two systems may be related. According to the paper, platypuses have a ten-chromosome–based system, where the chromosomes form a multivalent chain in male meiosis, segregating into XXXXX-sperm and YYYYY-sperm, with XY-equivalent chromosomes at one end of this chain and the ZW-equivalent chromosomes at the other end." Sex-determination system is also helpful It sounds to me like platypuses have both ZW like and XY like sec chromosomes. My guess is that this is similar to their ancestors including their last common ancestor with birds. Birds eventually moved to ZW exclusively as did some fish and insects. Mammals moved to XY exclusively. Reptiles largely lost this completely and depend on temperature. I presume the journal article will provide a lot more answers. Don't forget to consider convergent evolution in any thoughts you have. Also do remember that modern true reptiles, even those considered living fossils like the tuatara are not the last common ancestor of birds, not even close (recent taxonomic and molecular work has shown that they have changed significantly since the Mesozoic era) Nil Einne (talk) 17:36, 6 July 2008 (UTC)


 * Evolution of sex may be helpful too Nil Einne (talk) 17:42, 6 July 2008 (UTC)

The LHC and the end of the world
Recently, someone asked here whether or not the Large Hadron Collider would cause the end of the world. Our answer was, of course, inconclusive but if you're keeping track, you can at least find the minimum value of how much longer we have here. Just FYI...

Atlant (talk) 21:00, 5 July 2008 (UTC)


 * Personally, I'm convinced the continued failure of the LHC to go online is a global example of quantum immortality ;-) Someguy1221 (talk) 21:18, 5 July 2008 (UTC)


 * Hi. Um, I thought the website said it was going up tomorrow, but now it has apparently been moved to next month, what's going on? Thanks. ~ A H  1 (TCU) 23:40, 6 July 2008 (UTC)

What the hell is going on here!?
Quantum gravity, quantum black holes, quantum chemistry (?!!). gravity bends time (and is really just acceleration), multiverses, etc., etc., etc. The world of the big and the small is just so mentally.....megawhelming! Please, -someone help me get a grip!--THE WORLD&#39;S MOST CURIOUS MAN (talk) 21:32, 5 July 2008 (UTC)


 * Quantum gravity, quantum black hole, quantum chemistry, general relativity, multiverse...You'll really have to ask a more specific question if you want us to help you find an answer. Someguy1221 (talk) 22:04, 5 July 2008 (UTC)
 * Quantum theory in general? Fribbler (talk) 22:59, 5 July 2008 (UTC)


 * Instrumentalism might make you feel a little more comfortable as a way of reading scientific theories. Or less. I think it was Steve Martin who said that, "College philosophy teaches you just enough to really fuck you up." --Shaggorama (talk) 00:33, 6 July 2008 (UTC)


 * From a purely corporate point of view I can tell you that these scientists can "suck my ./..", when a scientific realm has products you can buy then I'd worry if I didn't understand, and maybe take notice of what they were saying.
 * Hope that helps with your 'megawhelmedness', capitalism loves you, and protects...87.102.86.73 (talk) 16:12, 6 July 2008 (UTC)
 * Seriously though there probably is name for the point of view of 'show me something that works', probably not a popular point of view in some circles... Good luck!87.102.86.73 (talk) 16:13, 6 July 2008 (UTC)
 * Better not go for an MRI then, you might come face to face with the quantum device that makes it work, then you'll have to come back here and strike-through your post. Franamax (talk) 20:04, 6 July 2008 (UTC)
 * Or use GPS, which requires those pesky "gravity bends space and time" corrections. --Stephan Schulz (talk) 22:01, 6 July 2008 (UTC)
 * Or use a working device using quantum entanglement for secure distribution of encryption keys. Heck, you might even be able to buy shares someday! Franamax (talk) 23:16, 6 July 2008 (UTC)
 * The above would be of use if I were sick, lost and paranoid.. What if it want butter on the other side of the bread?87.102.86.73 (talk) 14:01, 7 July 2008 (UTC)
 * Well, you could spread it on the wrong side and hope for quantum effects to redistribute it as desired. Or you could just put the butter next to the bread and hope for the best. Better get an XXL Finite Improbability Generator, or you might be in for a long wait. --Stephan Schulz (talk) 14:08, 7 July 2008 (UTC)