Wikipedia:Reference desk/Archives/Science/2011 May 6

= May 6 =

Trash on the moon
How hard/easy is it to directly observe some of the man made objects on the lunar surface? I believe the "bases" of the LEMs are the largest of these objects? What type of telescope (magnification, focal length, etc) would be adequate to make the objects clearly recognisable? Roger (talk) 09:00, 6 May 2011 (UTC)


 * This recent discussion may provide some idea Reference desk/Archives/Science/2011 April 29 Nil Einne (talk) 09:34, 6 May 2011 (UTC)


 * More from the archives I found Reference desk/Archives/Science/2009 July 18 which links to . Nil Einne (talk) 09:41, 6 May 2011 (UTC)


 * As a more recent followup to the 2009 LRO comment, that project has now advanced...see Lunar Reconnaissance Orbiter for images. Now whether that's recognizeable to an untrained eye? However, it's a good gauge for OP how much can be seen from moon orbit using dedicated instruments designed to do this, vs off-the-shelf equipment from earth. Might be some info (or at least an interesting read) at Third-party evidence for Apollo Moon landings. DMacks (talk) 09:52, 6 May 2011 (UTC)


 * For clarification the images available at the time were . I can't find much discussion of the Apollo rovers but the Soviet ones were identified Nil Einne (talk) 10:43, 6 May 2011 (UTC)


 * Looking at those pics, it seems that, with the exception of the foot path, the junk can be identified by being more reflective (shinier) than the surroundings. This suggests that a computer program could search for junk on the Moon by checking the brightness of every pixel. StuRat (talk) 01:38, 7 May 2011 (UTC)


 * See Third-party evidence for Apollo Moon landings for some photos. Bubba73 You talkin' to me? 23:23, 8 May 2011 (UTC)


 * Actually the easiest to observe are probably the retro-reflectors installed by the Apollo missions, any sufficiently powerful laser can be bounced off them and receive a distinctive return in the form of an abnormal spike in the light level at that wavelength. HominidMachinae (talk) 23:34, 10 May 2011 (UTC)

some disease without symptoms
hi i had heard about it twice in my life till now, it is a disease of something else i donot know but it dosent show any symptoms and body temperature rises high with weakness only this can u guess what this is.....thanx —Preceding unsigned comment added by Myownid420 (talk • contribs) 09:20, 6 May 2011 (UTC)
 * A rise in body temperature with weakness is itself a symptom that only a qualified doctor should be asked to diagnose. We cannot give medical advice. Cuddlyable3 (talk) 12:05, 6 May 2011 (UTC)
 * Fever is a symptom of numerous infections and medical conditions. You would need a doctor to perform some tests in order to work out which one. --Tango (talk) 17:43, 6 May 2011 (UTC)
 * Yes, a fever is a symptom. This raises the question: Is there such a thing as a disease that has no symptoms? ←Baseball Bugs What's up, Doc? carrots→ 19:05, 7 May 2011 (UTC)
 * If it doesn't have some negative consequence, it's not a disease. Any such consequence is a symptom. As such, a disease must have at least one symptom. — DanielLC 00:50, 8 May 2011 (UTC)
 * I suppose you could have a disease with no symptoms other than death, but death would still be a symptom. --Tango (talk) 01:21, 8 May 2011 (UTC)
 * But how could the disease cause death without screwing things up? When cells start to die, you get symptoms.  Googlemeister (talk) 13:30, 9 May 2011 (UTC)


 * Such a thing would not be a disease because, as the name implies, a disease causes disfunction of some kind. On the other hand there are viruses and bacteria that you can contract that have no symptoms at all.  It was once thought that Toxoplasma gondii was one of those, but since we've found that it can have remarkably subtle effects (including increasing the likelihood of traffic accidents, increasing intelligence and causing 'susceptibility to guilt').  HominidMachinae (talk) 20:04, 10 May 2011 (UTC)

DNA-Identification
The DNA comparison at Mass. Gen. was done with tissue samples from a sister of Osama and samples taken from the body. To my understanding you can conclude from the results that the two people were brother and sister, right? Any more conclusions which can be drawn? Is it known, exactly which DNA-analysis was performed? References? Thanks 213.169.161.199 (talk) 10:45, 6 May 2011 (UTC)


 * Both a sibling relationship and a parent/child relationship should feature half the chromosomes in common. However, in the case of the parent/child relationship, it should be exactly half (barring mutations and other abnormalities), whereas siblings only average half, but could theoretically vary anywhere from no chromosomes in common to 100% (although these extremes are so unlikely that probably no siblings ever had either case).  So, if they share something close to half the chromosomes, but not exactly half, that's fairly conclusive they were siblings.  Lower percentages in common would indicate more distant relations, like uncle/aunt.  However, if you have a population with significant inbreeding, this can complicate matters, since you can no longer assume that the parents each start with a unique set of chromosomes. StuRat (talk) 16:32, 6 May 2011 (UTC)


 * I'm not sure but it sounds like you are confused about how meiosis and inheritance works. Because of chromosomal crossover, chromosomes are not generally inherited as discrete units (except from the X and Y chromosome for the father) and it is entirely resonable to presume a child will have no chromosomes the same as their mother (and father excluding X or Y) even barring mutations and other abnormalities. Nil Einne (talk) 17:25, 6 May 2011 (UTC)


 * I've seen suggestions several relatives were used. In that case presuming we're including relatives from the male side you can probably conclude is that there was no non-paternity event. Nil Einne (talk) 17:32, 6 May 2011 (UTC)
 * If, from all the siblings, this sister and Osama were the only children of the same mother, a further reaching conclusion could be drawn. Anybody knows, whether there was a more scientific statement of the Mass. Gen. analysis than the one from TV 5 (Boston)? 213.169.161.199 (talk) 06:48, 7 May 2011 (UTC)

Unkown Bird
Can anyone identify this Bird? http://i51.tinypic.com/21k9dep.jpg —Preceding unsigned comment added by 182.178.250.127 (talk) 12:23, 6 May 2011 (UTC)
 * Where? HiLo48 (talk) 12:29, 6 May 2011 (UTC)


 * It is indigenous to Yahoo! Answers, apparently - 91.125.193.37 (talk) 12:36, 6 May 2011 (UTC)


 * Both the IP and the Yahoo! Answers questioner appear to be from Pakistan although I admit I was a bit surprised by this as the paper appears to have a long story on badminton and I wasn't aware that sport was followed much in Pakistan. Nil Einne (talk) 12:59, 6 May 2011 (UTC)
 * Yes it was mentioned in this forum post http://www.wiredpakistan.com/forums/viewtopic.php?id=17207 —Preceding unsigned comment added by 182.178.250.127 (talk) 13:33, 6 May 2011 (UTC)
 * (e/c) It's a kestrel of some sort. My guess is that it's a lesser kestrel, but they all look fairly similar. Matt Deres (talk) 13:39, 6 May 2011 (UTC)
 * lesser kestrel is mentioned as Vulnerable, so shouldn't this bird be donated to a zoo etc ? Nil Einne badminton is really popular in Pakistani schools. —Preceding unsigned comment added by 182.178.250.127 (talk) 13:43, 6 May 2011 (UTC)

astronomy question
Lets say I look at a star from the earth and it's 100 light years away, so I am seeing it as it was 100 years ago.

If I look through 10x binoculars do I see it as it was was 10 years ago? —Preceding unsigned comment added by 92.17.3.14 (talk) 14:53, 6 May 2011 (UTC)
 * No, you get 10 more light, but the light will still be 100 years old. Googlemeister (talk) 15:29, 6 May 2011 (UTC)


 * You don't get necessarily 10 times the light. The amount of light you get depends on the diameter of the main lenses of the binocular, not on its magnification. Dauto (talk) 15:49, 6 May 2011 (UTC)
 * Indeed. For a given size of main lens, higher magnifications will have correspondingly dimmer images at the eyepiece. TenOfAllTrades(talk) 01:11, 7 May 2011 (UTC)

(ec) :No, the light you're seeing still travelled for 100 years. It's a sort of optical illusion you're seeing through the binoculars. --TammyMoet (talk) 15:31, 6 May 2011 (UTC)
 * Optical illusion isn't the way I would describe it: I would just say "optics" (no illusion involved)! We have an article on magnification, and a brief section on telescopic magnification (as it generally applies to binoculars); and of course, our binoculars article describes in detail the specifics of a binocular optical system.  Note in particular the prismatic "flip" to make the image appear right-sided-up, unlike a straight telescope with equivalent magnification.  Nimur (talk) 18:13, 6 May 2011 (UTC)
 * Yes you're right, I only thought while I was driving that the word I was looking for was "manipulation" rather than "illusion". --TammyMoet (talk) 19:00, 6 May 2011 (UTC)


 * Interestingly, this is the third time I've seen someone express this misconception. I wonder how common it is, and where it comes from? thx1138 (talk) 19:29, 6 May 2011 (UTC)
 * Well, the image formed by a conventional binocular optical system is technically called a virtual image. Perhaps you've heard this terminology, and might have conflated "virtual" with "illusory"?  Would it seem less like an optical illusion, if the binocular could project its image on a screen (like, for example, a Newtonian telescope can do?)  Ultimately this boils down to mostly a matter of semantics; everything we visually perceive is an "illusion" of some form or the other; the only question is whether the "rays" converge at a specific focal plane, when analyzed via a geometric optics treatment.  Nimur (talk) 00:36, 7 May 2011 (UTC)
 * Sorry, I meant the misconception in the original question, that telescopes see light earlier than it reaches the naked eye. thx1138 (talk) 19:20, 9 May 2011 (UTC)

Current state of photovoltaics in Europe and the world
Where can I find an extensive report about the current state of the photovoltaic industry in the world? Thanks. --Belchman (talk) 16:26, 6 May 2011 (UTC)
 * A Google search for "current state of the photovoltaic industry in the world" finds this as the second hit. Looie496 (talk) 17:34, 6 May 2011 (UTC)
 * Thanks, though I'd need something less technically oriented and more economically-oriented, if that makes sense... --Belchman (talk) 20:46, 6 May 2011 (UTC)

Metal Gear
Is it even possible for something like metal gear rex or  ray  from the metal gear solid  series to even exist. --93.107.220.94 (talk) 18:55, 6 May 2011 (UTC)
 * Are you talking about Metal_Gear_(weapon)? Walking tanks with heavy armor and railguns may not be especially plausible (or worthwhile) with current technology, but I don't see anything at a glance that would make such a thing impossible. Is there some specific feature of this fictional machine that seems impossible to you? SemanticMantis (talk) 19:12, 6 May 2011 (UTC)
 * I'm pretty sure it can't fire off a railgun that powerful without the recoil sending it through the ground, although I'm not sure if they ever say that doesn't happen. It would be pretty pointless to put a weapon like that on a walking tank, since you could put it literally anywhere and have the same effect. I'm not sure if a railgun can be made efficient enough to not just vaporize the nuke when it fires, and I'm not sure you could make a nuke that would survive that. I think the acceleration required would be enough to set off any explosives. Everything besides the railgun is probably not worth building, but you still could. — DanielLC 21:29, 7 May 2011 (UTC)


 * railguns are actually very efficient in terms of recoil, you could accelerate small bullets to relativistic speeds without enough recoil for a tank-sized hunk of metal to feel it. On the other hand that same abundant mass that means recoil is the least of your worries means that ground pressure is your biggest concern.  As the Russians found out with the Czar Tank, anything that relies on small surfaces to rest on would have serious issues in any practical battlefield situation.  Think of it this way, as height increases, weight increases exponentially, any "walker" is militarily impractical for that reason. HominidMachinae (talk) 21:25, 10 May 2011 (UTC)

worker ants
Are the worker ants in a single colony usually genetically identical to each other? Googlemeister (talk) 19:20, 6 May 2011 (UTC)
 * If the colony has one queen then yes. Some species have several queens in a colony so they'll be different 82.43.89.63 (talk) 19:44, 6 May 2011 (UTC)
 * No, they aren't. Workers come from fertilized eggs and are diploid. See haplodiploid sex-determination system. An exception is Wasmannia auropunctata.  Sean.hoyland  - talk 20:05, 6 May 2011 (UTC)


 * (EC) No, they are not clones, contrary to the IP above. See Haplo-diploid_sex-determination_system. In short, sister worker-ants share 75% of their genes. SemanticMantis (talk) 20:08, 6 May 2011 (UTC)
 * Also bear in mind that mating with multiple males is common which adds further complexity to their internal make up even if there is only one queen.  Sean.hoyland  - talk 20:22, 6 May 2011 (UTC)

Relativity vs quantum mechanics
I got an impression that Einstein's relativity is more God-friendly (that is more favorable to intelligent design conjectures behind some phenomena) than quantum mechanics and is generally more flexible than quantum mechanics, allowing such things as wormholes etc. Is it right? I also think that quantum mechanics is less verified than the relativity theory and because of likely flaws can not be unified with relativity within the unified field theory framework at all. --89.76.224.253 (talk) 20:25, 6 May 2011 (UTC)


 * Your question appears to depend on a subjective view of what is "God-friendly". Since discussions about God are not really a part of science, I'm not sure we can give you a good answer. Perhaps if you gave a more concrete explanation of what you mean by "God-friendly", we could address whether relativity / quantum mechanics exhibits those characteristics. In general though, both theories expand our understanding of the physical laws that appear to govern our universe. As the number of things that science can explain increases, the number of things potentially attributable to "God" would tend to decrease. In all probability there will always be things beyond the limits of scientific understanding that might be attributed to "God", but placing God solely in the role of filling in the gaps would often lead to a very different view of God than that popularized by most religions. Dragons flight (talk) 20:38, 6 May 2011 (UTC)


 * The problem in trying to compare GR and QM this way is that they deal with really quite radically different domains of physics, which only converge in a few places. They are both highly successful theories — this is why it is so striking that they have as of yet still resisted unification, because it is really unthinkable that either are extremely wrong. It is not really an either/or situation — they are both about the same level of "verified", even in their weirder aspects. There are loads and loads of experimental verifications of both of them at this point. I don't see how either are more "God-friendly", frankly. You can interpret either in "God-friendly" ways, it's all in how you define "God-friendly." --Mr.98 (talk) 20:51, 6 May 2011 (UTC)

QM allows God to gamble. Count Iblis (talk) 21:32, 6 May 2011 (UTC)
 * For readers who don't understand this remark (which shouldn't be taken too literally), see Bohr–Einstein debates. Red Act (talk) 22:00, 6 May 2011 (UTC)
 * Also, it's only a certain interpretation. The many worlds interpretation is deterministic. — DanielLC 20:58, 7 May 2011 (UTC)

Ralativity allowing such things as wormholes and QM allowing MWI, thanks —Preceding unsigned comment added by 87.68.158.147 (talk) 07:26, 7 May 2011 (UTC)
 * From your examples, I guess you're looking for ways that a large supernatural being could hide out somewhere and not be detectible through telescopes, like hanging out at the other end of a worm hole, or in a nearby MWI-style universe? Conceptions of God vary widely, but God in Abrahamic religions is largely imagined to be transcendent, which is a poorly-defined mechanism by which god can interact with physical existence without existing within it.  If you're looking for a physical mechanism by which transcendence could work, it doesn't seem to me that either relativity or quantum mechanics would provide such a mechanism.  Both branches of physics describe the orderly ways that physical existence behaves.  There is no mechanism in either for physical existence behaving in an unexpected way.  Both branches make specific predictions about how physical existence will progress, either in a deterministic sense in the case of relativity, or in a probabilistic sense in the case of quantum mechanics.  If anything outside of physical existence were to affect physical existence, that would result in the predictions of either relativity or quantum mechanics being wrong.  I.e., transcendence is inconsistent with either branch of physics.  Red Act (talk) 08:53, 7 May 2011 (UTC)
 * Of course those of us who believe that God "is all, and in all" see no dichotomy between quantum theories and Einsteinian theories. --TammyMoet (talk) 09:17, 7 May 2011 (UTC)
 * God can't hang out in a nearby MWI-style universe. How near they are is just how similar they are. If he was in that universe and not this one, they'd be astronomically far away. Also, you can only effect your own universe and those in your immediate vicinity (or just yours, depending on how you define "universe"). — DanielLC 20:58, 7 May 2011 (UTC)
 * The theory is that God is "outside of time", hence He is in some "dimension" that humans cannot observe, but God can observe everything, all at once. ←Baseball Bugs What's up, Doc? carrots→ 21:08, 7 May 2011 (UTC)
 * My point is that an MWI-style universe would not allow this. Also, a dimension is essentially a direction. Please don't use it to mean an alternate reality. — DanielLC 00:44, 8 May 2011 (UTC)