Wikipedia:Reference desk/Archives/Science/2015 January 13

= January 13 =

Can dogs survive in the wild?
I'm trying to convince my idiot friend that evolution is true, and dogs proves it. I tell him to look at all the different kinds of dogs there are, and since these animals were made by humans via artificial selection, that proves that evolution is a fact. But he's dumb, and says that god made them all. So I want to counter that by saying that god couldn't have possible made them because dogs can't survive without humans taking care of them. I'm fairly certain that dogs, even large ones like Great Danes and what not can't survive in the woods without humans taking care of them, but I just want to make sure. Keep in mind, I'm not talking about animals like the dingo which used to be domesticated, but evolved to revert back to their feral state. 69.121.131.137 (talk) 03:09, 13 January 2015 (UTC)


 * Unfortunately, they can survive on their own. Many third world cities (without dog catchers) have large stray dog populations.  StuRat (talk) 03:30, 13 January 2015 (UTC)


 * Artificial selection does not prove that "evolution is true". Whether "God made them" or not depends on how you define "God". ←Baseball Bugs What's up, Doc? carrots→ 03:31, 13 January 2015 (UTC)
 * More importantly, it depends on how you define "made". Evolution and God are not mutually exclusive concepts.  -- Jayron 32 01:26, 14 January 2015 (UTC)


 * For a casual proof of evolution, you might point out that the human spine causes all sorts of problems because, in evolutionary terms, we very recently began walking upright, and the spine design has not yet caught up. Specifically, I'd say the spinal chord should not be inside the spine, which leads to pinched nerves.  Instead there should be a tough, rubbery cartilage there, and the spinal chord should be more like a notochord.  Unfortunately, there's no evolutionary path to lead there, since a spinal chord half inside and half outside the spine is worst of all.  If God designed us, he would have presumably done a better job of it. StuRat (talk) 03:34, 13 January 2015 (UTC)


 * It isn't worth arguing with someone who doesn't think that human selective breeding is responsible for various breeds of dogs or of livestock. That is agreed even by most creationists.  Whether dogs can survive in the wild, as mentioned, depends on the breed.  Some can survive in the wild.  The original poster is trying the impossible, which is to persuade someone whose mind is made up.  It is fortunate that the characterizations made by the OP apply off-wiki, because calling another editor "dumb" or an "idiot" on Wikipedia would be personal attacks.  I suggest that the OP, first, tone down his or her rhetoric about someone who isn't here, and, second, stop wasting time trying to reason to someone who isn't listening to reason.  Also, creating an account has advantages.  Robert McClenon (talk) 03:38, 13 January 2015 (UTC)


 * StuRat meant to say they have large populations of stray dogs, not populations of large stray dogs. And no, evil breeds, like the chihuahua, and monsters like the Great Dane cannot survive as such breeds in the wild.  Only those dogs that maintain a form close to what God made (the Dingo, the German Shepherd) can survive without human sinfulness. μηδείς (talk) 03:41, 13 January 2015 (UTC)


 * Depends what you mean by "wild". Somewhere like Arcadia, sure. In 2010 Iraq, a little tougher. In between, there are many free-ranging dogs doing about as well as God may have intended for each. Even pussies are tough enough to ditch humans. InedibleHulk (talk) 03:44, 13 January 2015 (UTC)


 * You describe Greece as uncivilized, and StuRat thinks humans should be spineless? What's next? μηδείς (talk) 03:48, 13 January 2015 (UTC)
 * Fixed the Wikilink. Meant the truly uncivilized fake place in Greece. Where God lives. InedibleHulk (talk) 03:51, 13 January 2015 (UTC)


 * It's not going to work. You can show them all the scientific evidence there is. Denialists by the very definition, choose to disregard all evidence that opposes their personal views. If you truly want your friend to seriously consider the viability surrendering their willful ignorance, you'll have to debate the matter on their field of choice - you'll have to make a well thought-out theologically based argument. As an aside, it will be much more difficult to persuade them while you're insulting them, directly or by implication.
 * Dogs have a good chance of surviving in the wild, since their instinctive ability to hunt and scavenge is genetically hardwired into them. I'm afraid you haven't quite got that one right. Plasmic Physics (talk) 03:46, 13 January 2015 (UTC)


 * Your friend is only an "idiot" if he thinks that dog breeds have always been around and is in denial of artificial selection. But even if he knows what artificial selection is, "God" (i.e. natural biological processes) made those breeds. And either way, it doesn't prove anything about evolution. ←Baseball Bugs What's up, Doc? carrots→ 03:50, 13 January 2015 (UTC)


 * You might point your friend to Five Proofs of Evolution, or just let him continue with his belief system. Alansplodge (talk) 09:02, 13 January 2015 (UTC)


 * I think you're barking up the wrong tree (pun intended) here. If God created all the different breeds of dog, then surely there shouldn't be any more new breeds being recognised? Well guess what: on 1st January, the American Kennel Club recognised 4 new breeds of dog. Did God just wave his hand and say "I guess I'll just create a new dog breed"? Or did some breeders develop a breed over many years? You need to get in touch with the AKC and investigate the history of the new dog breeds, find who their (human) originators are, and get a statement from them. Your friend is not dumb for his blind faith in Creationism, he is dumb because he is wilfully ignorant of real life. --TammyMoet (talk) 09:57, 13 January 2015 (UTC)


 * I'm with the above answers but I'll leave an additional note that whatever your friend may have said, I think you'll find creationists more commonly claim that artificial breeding doesn't produce new species, the claimed microevolution vs macroevolution distinction, (all wrong in many ways, as explained in our articiles), and that artificial breeding is simply "destroying information" so it isn't surprising if some dogs would have poor survival were it not for humans. To be clear, these are poor arguments with many holes, I mean creationists come up with silly things like the alleged perfection of the banana (which I think even the inventor acknowledges was a dumb argument), but the point is you aren't likely to get anywhere by arguing whether or not dogs can survive in the wild (which isn't to say you'd get anywhere by pointing our more substanial flaws). Nil Einne (talk) 11:22, 13 January 2015 (UTC)
 * BTW, I would add even if your friend wants to suggest all the different dog breeds were made by god, their likely argument in response to any of your claims that they can't survive in the wild would simply be that that's how god created them intentionally because they were intended to be companions to humans, and they weren't intended to survive in the wild, similar to the banana argument, or many other things like that. Of course, as mentioned by others, it seems difficult to sustain the idea that all breeds were created by god, since we're creating new ones, so ultimately it seems likely your friend will have to accept that some breeds were basically created by humans, even if they're then likely to fall back on to other arguments like those I highlighted. (You can also get in to arguments about why god created dogs breeds primarily intended to attack other animals or even humans, when god didn't want any of that but that's not an argument unique to dogs. And in any case, it's likely creationists will suggest that these dog breeds were only created by god after the downfall of Eden or he created them because he knew it was going to happen even if he didn't want to or even simply they weren't like that before Eden despite having the teeth, build etc suited to that purpose and it's not god's fault it all changed after Eden despite him designing them in such a way they seemed well suited to change when humans broke Eden .) Nil Einne (talk) 17:22, 13 January 2015 (UTC)

To begin with, artificial selection isn't really quite the same thing as natural selection after all. The problem is that the human breeder eagerly picks out genes of large effect that have many pleiotropic consequences, which won't actually be used for evolution in the wild. (This effect is stronger in a lab setting, e.g. mutating fruit flies with radiation, where huge deletions of the genome may be brought about that practically never happen in normal evolution; some of the confusion over this ties into the "hopeful monster" concept) The result is that the human-made breeds tend to be more sickly in ways that a slow, sane pace of natural selection wouldn't have caused. Now to be sure the dogs, if released to the wild, should still survive; eventually they will ditch the worst large-effect mutations and, if they still need the trait the breeder selected for, find small effect mutations that affect it more precisely.

Now as to your argument, presumably your friend recognizes that there are breeds of dogs that exist now that never existed in the past; yet he says God created them. That means that he recognizes that something created by God doesn't have to date back to Noah's ark; God is allowed to have a plan for something to appear. Now if that is so, then you and he are arguing over very little, because no scientist will argue that something will evolve unless it is physically possible and indeed is a pretty good solution to the ecological problems of its niche. In religious terms, unless God planned it. Wnt (talk) 14:49, 13 January 2015 (UTC)


 * I don't think your argument about dogs is a good one.  Evolution requires three things:  One is that living things inherit characteristics from their parents - another is that natural selection favors plants and animals that are better able to reproduce than others, the third thing is that the process of inheritance makes mistakes (albeit rather rarely).   The situation with dogs shows that dogs inherit characteristics from their parents - a poodle plus another poodle results in a whole lot of poodles.  But it doesn't demonstrate that dogs that are better suited to their environment reproduce better - to the contrary.  It's unlikely that a highly specialized pedigree dog will have fewer defects than a 'mutt'.  Inbreeding has caused all sorts of defects to develop in pedigree dogs - and the very "best" of them are far more likely to have a hard time reproducing than a dog that's some random mix of many breeds.   Also, the "selection" process isn't "natural selection" - it's clearly human intervention...which is almost like an "intelligent designer" at work.


 * So what you need is a much better example. There are two examples that I think are compelling - but they both take a bit of investigation.   If your friend is simply dismissive of your ideas, then you're unlikely to get him/her to sit still long enough to be convinced.
 * Peppered moth evolution is a classic. These moths were colored white with little black speckles to match the lichen and tree bark in rural England.   Up until around 1811, there had been no examples of these moths in any other patterns.   But gradually, butterfly collectors noticed an increasing number of black peppered moths showing up.   It turns out that the smoke and pollution from industry in the areas where the moths lived was coating the trees with dark soot.   Within a decade or two, almost all of the moths were black...then, when the Clean Air laws were passed and the amount of smoke in the air decreased spectacularly, the black moths became rarer and rarer until today, you can't find a single one.   Clearly the moths were evolving to be better camoflaged against the trees - and then evolved back again when lighter colors worked better.
 * The Recurrent laryngeal nerve in mammals - and especially in the giraffe is a fascinating demonstration. It seems that the vocal chords (the larynx) evolved from a greatly distorted gill from each side of some primordial fish.  The nerves going to each of the two gills on that original fish had to bypass the arteries going to the heart - the right one went over the artery, the left one, under...and modern fish of all species are just like that.  No big deal if you're a fish.   But as the two gills moved closer together over millions of years of evolution - one nerve was forced to loop past the heart.   So in a giraffe (or a human, or almost any other animal) - the nerves controlling the right side of the larynx go directly from brain, down the neck for a short distance to the larynx...but the left side nerve goes from the brain, all the way down to the heart, around that artery, then all the way back UP the neck to the larynx.   In humans, this is no big deal - but in a giraffe, it means that one nerve is about 15 feet longer than the other.   Since electrical signals from the brain have to travel 15 feet further to get to the left of the larynx than to the right, this makes it almost impossible for the poor giraffe to coordinate the muscles in the larynx.   This is why giraffes are almost the only mammals that don't make vocalizations.   Now, your friend needs to explain why god decided that all animals have to have this nerve looped around that artery...it makes no sense whatever.   If "God" designed the giraffe, he was not the "intelligent designer" but rather the "bloody stupid idiotic designer".   Sure, you might argue, he may have decided that giraffes don't need to make a noise - but then why bother having a larynx - let alone bothering to connect up a nerve in such a totally crazy way?   Why would ALL air-breathing animals from dinosaurs, to humans and giraffes have such an unbelievably stupid design?   Any rational design would have both nerves going the short way to the larynx...and if they did, then the spectacular song of the male giraffe during gentle courtship of his mate would grace the plains of Africa as testimony to God's Greatness...but no.   If hard-pressed, a giraffe can make a sound that's been described as a cross between a bleat and a cough.  God did not make the giraffe...it's just not credible...it evolved from a fish - and when you look at the evidence with an open mind, there is really no other conclusion.


 * These are great examples...there are many, many more. Why do some people have lactose intolerance?  Why do some people inherit sickle cell anemia?   Why do bacteria develop immunity to drugs in hospitals?   Why do rats in New York have genetic immunity to Warfarin?   Why do rabbits in Australia have genetic immunity to mixamatosis? All of these things are clear demonstrations of evolution happening on human timescales.   There are several long-running experiments where bacteria are forced to evolve by changing their living conditions - and they change over time, in exactly the way that evolution predicts.


 * It's actually very hard to imagine how evolution might NOT occur. If the shape and nature of an animal or plant derives from it's DNA (which is hard to deny) - and if DNA is replicated from parent to offspring (also, hard to deny) - and there are occasional errors in that copying process (again, hard to deny) - then occasionally, a small variation will occur in a plant or animal.   If that variation makes it reproduce a little more efficiently than the others of it's species, then its genes will (inevitably) be copied into more of the next generation than the original genes - and gradually, more an more of the members of that species will carry that gene.  Eventually, every plant or animal in that species will have the new and improved gene.  Evolution has happened.  Do that enough times and you get human beings from fish.


 * We can even see evolution happening in systems that are not biological in nature.  If a song or a TV show or a movie becomes successful through some clever innovation, other makers will tend to copy that idea.  Making a movie is expensive - and going with some crazy new idea is dangerous - so most of the time, they make variations on what worked before.  Movies that embody themes that fit the times make more money than those that don't - and that allows their makers to make more of them.  Hence you get huge waves of movie genres (cowboy films, film noire, disaster movies, etc) that come and go as the environment favors one or the other.   All of the essentials of evolution are there...movies that 'work' tend to produce 'offspring' that are broadly similar.   Movies that do well in the box-office earn more money and therefore inspire more copy-cats.  Movies that do badly are dropped and produce no copy-cats.  Over time, movies adapt to fit the viewer preferences.   You can see the same things happening in a huge range of fields.   Whenever there is copying with variations and pressure for things to do well or do badly, for reasons that the makers don't really understand - then evolution occurs.   Why is it that almost all cars come in silver or black - but almost none in purple?   I'm pretty sure it's evolution.


 * SteveBaker (talk) 16:51, 13 January 2015 (UTC)


 * If you absolutely MUST stick with the dog thing. Point to the Labradoodle.  A Labradoodle is a cross between a labrador and a poodle.   There are breeders all around the world that 'make' labradoodles by crossing parent dogs of those two breeds.   But, you can also take two labradoodle and mate them - and you get another labradoodle.   Clearly, god didn't make the labradoodle.   There was no 'labradoodle' breed before 1955...although presumably an occasional accidental mating of a labradore and a poodle would have happened, we didn't have a 'breed' of these animals that you can point to and say "Oh - look!  A labradoodle".     At this point, your friend either has to admit that god didn't design the labradoodle - we humans can make a labradoodle where there was no labradoodle before.   We can do it anytime we want.  Labradoodles are a stable, well-recognized breed.   Of course your friend is at liberty to claim that labradoodles aren't a "real" breed...so they don't count.   But then we have to look at other kinds of dog that he does claim are breeds that were made by god.   Maybe God made the Labrador?  Sadly, no.  We know that all labradors are descended from two very specific dogs...and, remarkably, we even know their names!  "Avon" and "Ned".   These dogs (which were known to be good gun dogs - but which were definitely not "labradors") were given by the Earl of Malmesbury to assist the Duke of Buccleuch's breeding program in the 1880s.  Before that, there were no Labradors...so we know for sure that labradors are "the work of man" - just like labradoodles.   If you go through all of the Wikipedia pages for various dog breeds, you'll find some (like the Labradoodle and the Labrador) who's origins are very well known and documented - and others (like the poodle) where we know only that the first known examples were around on some particular date.


 * So I suppose that your friend (if a rational, thinking person) would be forced to admit that Labradoodles were definitely NOT created by God, and more surprisingly, neither were Labradors. Of course (s)he may cling to the view that poodles are a divine creation...but at least one is forced to segment the world of dogs into the originally-created-by-God set - and the set that were created by man.   Now you have to ask whether some of the dogs in the "made by god" set really belong in the "made by humans" pile?   In the end, the only thing we really can deduce from human history is that the wolf was not created by man...but most dog breeds were.


 * Sadly, this doesn't get you any closer to an argument about evolution.  It does demonstrate that mankind is capable of producing new kinds of dogs - which I suppose breaks the doctrine that 100% of all species were made by God in the Garden of Eden.   There were no labradoodles in Eden. SteveBaker (talk) 17:19, 13 January 2015 (UTC)


 * Actually, if you cross a Lab and a Poodle you will get a Labradoodle. But if you cross a Labradoodle and a Labradoodle you can get everything from a Lab to a Poodle to a Dabraloodle to a Poobradaddle, to a Cobrababble, to an Oprahbubble, to an Oobracadoobra. From there it's just one small misstep to a Scooby Doo or a Deborah Messing.  See dihybrid cross. μηδείς (talk) 19:00, 13 January 2015 (UTC)
 * My wife and I went to a breeder with the idea to get one for a pet, they said that they used labradoodles to parent their puppies. This is confirmed in Labradoodle.  (In the end, we decided that labradoodles are not such great animals after all).  SteveBaker (talk) 19:45, 13 January 2015 (UTC)
 * Yes, if he's paying close attention, culling (i.e., selling) the less true-to-form puppies, and only breeding the ones with traits he wants, he'll eventually start getting mostly passable labradoodles. But they won't breed true unless it turns out that all the desirable and defining traits are homozygous. μηδείς (talk) 20:10, 13 January 2015 (UTC)
 * SInce people have been breeding labradoodles for close to 60 years, and aggressively so for 20 years - at maybe 2 to 3 years per generation, they're likely to have eliminated almost all risk of throwbacks. But they certainly don't yet have the complete uniformity of more established breeds - and already they're getting the inevitable genetic diseases starting to pop up.  However, the original point remains - we have labradoodles, they (mostly) breed true - and god didn't create them in the Garden of Eden.  Either humans created this breed or we have no free will.  Pick either one!  QED. SteveBaker (talk) 20:25, 13 January 2015 (UTC)


 * We're really getting into philosophy more than science here. A pointier version of this argument came up in the U.S. a year or so ago when Richard Mourdock was lambasted for saying that pregnancies following rape were part of God's plan.  Now I'm normally all for roasting a Republican, but this struck me as unfair, because the alternative position is to single out the kid in the class who was produced by a rape, point your finger at him and say "you are not part of God's plan".  We should think a bit more about what God's plan actually means first!  I think a good analogy is with the putatively endless set of contigency plans come up with by military organizations like the U.S. Army.  One kind of assumes that if Belgium ever decides to invade Virginia Beach, they have a plan for it.  My understanding is that theologians try to accept both that there is a divine plan for everything, even after all the weird events that have happened in history, and that there is free will, which makes for some creative logic, but so long as they believe God is omniscient and all-powerful it is nothing they can't handle.  The bottom line though is that there should be no litmus test for religion set up at a security counter at the classroom door - everyone is capable of learning what evolution predicts in terms of what we measure by natural means, regardless of what they think the theology behind it is; they should be able to recognize it is practically useful without having to believe any religious assertion that our lives are unplanned, random, meaningless, or insignificant. Wnt (talk) 18:27, 13 January 2015 (UTC)


 * The problem being that if you accept that all things that happen are a part of god's plan then you wave goodbye to free will because you're saying that the rapist didn't have a free choice to rape or not - he was merely being constrained to follow god's plan in the creation of this child whom you're claiming is indeed a part of the plan. That's a logical possibility, obviously - but the absence of free will is definitely contrary to most religious thinking - and would cause severe upset in society if it were true.   If the rapist is able to make a totally free choice - then one of those options has to be to veer away from any "plan" - and now you're forced to point to the kid in class and tell him that he's not a part of the plan.   Neither of those options are particularly appealing!


 * Furthermore, if everything that happens is a part of the plan - then god's plan boils down to the universe slavishly following the laws of physics - and if that happens then you don't need the existence of a god to explain things that happen because the laws of physics do a perfectly fine job of doing that. Then the existence of god boils down to a gross violation of Occams Razor...which is fine if you like that kind of thing...but is what ultimately leads me to scrap the entire silly idea.  SteveBaker (talk) 20:03, 13 January 2015 (UTC)


 * Well, ever see a Choose Your Own Adventure book? You have many choices to make, yet every one brings you to some page written by the author of the book.  I'm not saying that's way it is - there's a huge variety of philosophy possible here - but this illustrates how things can be neither random nor predetermined, and besides, if mankind is created in the Creator's image, it's always in our creative works that we'll find the most useful metaphors for understanding.  Nobody is denying that, so far as we can observe, the laws of physics seem to be valid.  But they always proceed from some starting point.  Is it really Occam's Razor-able that that starting point was some simple set of starting conditions "at" the Big Bang, even though it seems like the complexity of the events in the universe expands without limit the closer you look back toward it, and we know nothing about it?  Even though we then turn around and use the anthropic principle - itself more or less a form of creationism! - to say that somehow the "right" starting conditions were picked?  What if the starting conditions aren't set at infinity in an uncaring way for the random development of interesting life someday, but right here, right now, by some God who actually sees and cares about us?  It's all very mysterious, but beware of taking some (atheistic) religious assumption, dressing it up in sciencey garb and hiding it in the part of the theory of the cosmos that we don't actually know anything about. Wnt (talk) 20:24, 13 January 2015 (UTC)


 * Well, yes - let's take your analogy of the 'choose your own adventure' book. You're trying to tell the kid in the classroom that he's a part of the plan - but it's inconceivable that any other path than the rape of his mother would result in him being there.  In order to be who he is on that day with that specific birthday, it pretty much had to be the free will of the rapist that caused him to be there, on that day, with that eye and hair color and that birthday with a mother who was 15 years old when he was born, etc, etc.  There just aren't too many other routes through the 'choose your own adventure' book that would lead to that.  99.999999% of the other ways that free will could have directed us through the book would result in him not existing.  Let's face it, a free-will decision by Attilla the Hun would have resulted in a large fraction of the population of the world not existing...and Og-the-caveman could have picked a different wife and NONE of us would exist.  So this is a REALLY large book - and hardly any of the pages have you or I on them.


 * So what you have to imagine is that this one particular path through the book included this kid - but that there were many other paths ("plans of God") that would have resulted in him never existing...yet you're still going to tell him that he's a part of god's plan...although technically, you're saying "You're a part of plan number 153920423 of 1032534070734095738087230498 plans that god made but which didn't play out."  Taken to a very reasonable extreme, the location of the pencil on my desk right now is also a part of God's Plan - and my putting it there as an act of free will was just a page in this adventure book-style plan that included me deciding to put the pencil someplace else - 1/100th of a millimeter to the left, or to toss it in the trash, eat it...whatever.  This means that this plan book, ultimately resembles the "many worlds hypothesis" - where every possible bifurcation of reality at the quantum level results in another whole section of the "choose your own adventure" book.   That's fine - but again, we've arrived at a place where the laws of physics suffice to explain all of this - and your belief in god once again rests on denying free will, or denying Occam's Razor.   That's a very slippery path because then I have to ask why you'd choose this particular unlikely (but possible) denial of the razor rather than the near infinity of others...such as that SpongeBob SquarePants actually created the universe.  SteveBaker (talk) 20:52, 13 January 2015 (UTC)


 * I can't really say that idea is right (it is chosen more as a counterexample, after all) but when one considers the total number of 'plans' that could exist, not merely in infinity, but in an infinity of cosmoi, it doesn't matter how many numbered plans exist; each is still a truly unique inspiration. But bear in mind two things -- first, that since the laws of physics are time-reversible, each moment can have multiple pasts as well as multiple futures; and also, that they are nondeterministic, which means that it is possible that our fate might be nudged this way and that rather than proceeding along a random vector.  I think it is worth considering that our consciousness might exist with at least two dimensions of time - one in which the normal laws of physics operate, and one reflecting the progressive work by which God steadily revises and perfects the universe.  In keeping with accounts that "every tear will be wiped away", perhaps people pass into parallel worlds, keeping the virtues that they have attained by resisting evil, yet seeing all that evil pass from mind, and indeed, never even having been real at all, in some sense.  So while I mentioned one fixed 'initial condition' in the present above, actually I mean that there may be multiple initial conditions, with the time between them interpolated to fit using non-deterministic physics, so that it is possible for the author of the universe, with our input, to steadily revise the entire plot - past, present, and future - within his own dimension of time rather than the time frame that flows within the context of the story.
 * Now we've really gotten far off the point with this, but for this question: it's possible that God had in mind the form of a certain kind of poodle from a previous revision of the cosmos, or from some Eden (next door to "the" number line, and the place where the six regular polytopes that can exist in four dimensions might be found) or from some other sort of plan. It might not be without significance; it might not be random; we know it's not truly all our choice because we can't just breed up anything at all.  And the same is true of the species we share the planet with.  Of course, it will be so much easier to see if ever mankind were to visualize a foreign planet with its own kind of life, because I have little doubt that that world will have its own trees, which we may even be tempted to give familiar names, and its own fish, and countless other organisms we recognize, as well of course as a few residents of Eden who have not yet been spotted on Earth (but give our biologists time...) Wnt (talk) 22:18, 13 January 2015 (UTC)


 * It doesn't look like your notion of a mute giraffe checks out. Apparently they communicate largely in infrasound, which is inaudible to many people.  Even those people distinguish a variety of vocalizations though, including "alarm snort", "bleating or mewing" (calves), "roaring bellow" (females seeking young), "raucous cough" (males courting), "moaning, snoring, hissing, and flutelike sounds".   And after all... if that long, long recurrent nerve didn't work, why wouldn't it have degenerated into some vestige? Wnt (talk) 16:16, 14 January 2015 (UTC)


 * I generally recommend that you actually read the references that you post. If you had, you'd know that giraffes make infrasound noises only by physically moving their necks around to force air through their nostrils - which is where that sound actually comes from.  The fact that they have to go to all the trouble to throw their necks around to make noises is evidence that they can't use their vocal cords.  Kinda proves what I'm saying.  Other animals such as elephants and okapi that use infrasound for long distance communications still use conventional vocalization for short range work...but the giraffe doesn't do that.  The nerve hasn't degenerated because the necessary genetic changes to make it degenerate would have to have some measurable impact on reproductive capability.  Evolution isn't a perfect mechanism - it doesn't always get rid of unnecessary things.  But regardless of whether or what noises a giraffe makes - why would an intelligent designer route one of the two nerves by such an insanely circuitous path?  That would not be an "intelligent designer" that would be a "bloody stupid designer". SteveBaker (talk) 18:29, 14 January 2015 (UTC)


 * From what I'm reading the infrasound does come from the vocal cords. And the use of infrasound is shared with the okapi, with a short neck, as a way to avoid predators.   (Which is sort of curious because what on the savannah will mess with an adult giraffe?  But I guess once evolved there was no reason to lose it)  My purpose here is not to doubt that giraffes evolved, nor to deny that there is a clear evolutionary reason for the strange structure; but only to quibble on whether giraffes can vocalize and to mention that it seems silly to harp on it being such a "stupid" plan when really there's not much obviously wrong with it. Wnt (talk) 19:01, 14 January 2015 (UTC)

What is the difference between analgesic and sedation?
213.57.31.194 (talk) 05:01, 13 January 2015 (UTC)


 * Trying to explain would be relatively painless, but might put you to sleep, so read analgesic and sedative and decide for yourself. StuRat (talk) 05:12, 13 January 2015 (UTC)
 * There's also a small difference between sedatives and sedation. No article for analgesia. That's another difference. InedibleHulk (talk) 05:16, 13 January 2015 (UTC)


 * Briefly, analgesics are intended for use as painkillers. Sedatives are to reduce anxiety, irritability - generally to calm the user.  In many cases, analgesics are also sedatives and vice-versa - so there is considerable overlap.  A mild sedative might not directly act to reduce pain, but may reduce the anxiety and stress caused by the pain and thereby make it more bearable.  SteveBaker (talk) 16:04, 13 January 2015 (UTC)


 * It's easier to get the pain-relieving effects of a sedative without drugs than it is to mimic an analgesic. There's a section on "natural" inhibition of cyclooxygenase, but those are still chemicals you need to ingest. The key to relaxation is already in our head. Certain things just help (or aim to help) us reach it easily. InedibleHulk (talk) 01:39, 14 January 2015 (UTC)

Professional laptops
Why do many gamers and professionals, such as graphics designers or engineers, seem to use big, bulky, heavy laptops in this day of thin and portable devices? 194.66.246.5 (talk) 14:43, 13 January 2015 (UTC)


 * There's really no substitute for a large screen, which allows you to see details you just can't make out on a tiny screen, even at the same resolution. Similarly, a full-sized keyboard allows for faster entry than a compact keyboard.  And what are the advantages of being small ?  It won't fit in your pocket, in any case, so then it's just a question of whether the weight fatigues you as you carry it.  Most people can carry several pounds indefinitely without becoming fatigued. StuRat (talk) 14:48, 13 January 2015 (UTC)


 * Some of the laptops I see people using don't look portable though. It looks silly for example opening it up in a coffee shop due to its size. 194.66.246.5 (talk) 15:03, 13 January 2015 (UTC)


 * Well, obviously they are portable, if they were carried into a coffee shop. The more general question for any device is "How small is too small ?".  Traditionally, technology limited how small we could make things, but now we are getting to the point where the technology allows us to make something that is so small as to be unusable for other reasons.  Larger cell phones (especially flip phones), for example, allow a microphone by the mouth and a speaker by the ear, which makes for much better communication.  Here the upper limit is probably that it needs to fit in a pocket, but there's not much point in making it much smaller.  You also want to be able to hit all the buttons by hand, not have to use a stylus, and with a full QWERTY keyboard there are a lot of buttons, so the space adds up.  And people want a longer battery life for any device, which requires bigger batteries. StuRat (talk) 15:21, 13 January 2015 (UTC)


 * I don't know exactly what models you're thinking of, but people doing graphics-intensive work are surely going to want a large display. They may also want more options for what can be attached or inserted, such as an Ethernet connection, USB, and a Blu-ray disc. Jc3s5h (talk) 14:51, 13 January 2015 (UTC)


 * So are all these portable laptops these days which manufacturers claim are ultra thin and light made at the expense of performance? 194.66.246.5 (talk) 15:00, 13 January 2015 (UTC)


 * In some respects, yes. Certainly you can pack twice as much into a laptop twice the size.  But eventually we will hit a point where you can pack more than enough memory, storage space, battery etc., into as small of a space as you would want.  Then we hit those ergonomics limits.  There are some possible workarounds, like a roll-up keyboard and screen, to make it more portable without being unusably small. StuRat (talk) 15:31, 13 January 2015 (UTC)


 * I'm one of those people - I write C++ realtime 3D graphics code for a living (I'm currently doing "augmented reality" stuff).  I don't often haul any of my laptops around with me (I have 4 of them!) - but when I do, it's because I need the power of a decent computer - otherwise I'd use a tablet or even just my phone with a folding bluetooth keyboard.   Those little folding keyboards are surprisingly comfortable to type on.   So the need for a really good laptop is a combination of wanting a full-performance GPU, a good sized screen with really good back-lighting, a high-horsepower CPU and a ton of memory + disk space.   The super-thin computers tend to have poorer everything.


 * It would be different if I was some kind of executive who needs to be able to do email and display powerpoints in airport lounges...and not much else. When you need your laptop to compile a million lines of C++ code - or to debug subtle graphics glitches - you really need something with some 'oomph'.  All of that horsepower also makes the laptop consume a ton of energy - so you need chunkier batteries and active cooling - all of which adds considerably to the weight and thickness.  The large screen and decent backlight makes that even worse.  But since I'm only using it when I absolutely need that much power (and when I absolutely can't do it at home or in my office) - then that's the best option.


 * In addition to my big Dell laptop, I do actually have an HP "Chromebook" - which essentially runs a browser and nothing else, has very little local storage and doesn't even have a hard drive, and an old "netbook" - which I like because it's physically tiny - but which has been supplanted by the Chromebook. The battery life on the chromebook is incredible and it's very lightweight.  That's great for taking on vacation  and leaving in the car for occasional use.   It's better than a phone or tablet - but useless as a general purpose computer.   My big-assed Dell laptop is good for heavy-duty work - but I wouldn't want to lug it around with me everywhere.   My day job bought me an Apple laptop - it's like a piece of jewelry - pretty to look at, pleasant to the touch, fancy magnetic power cord (why?!) - but falls between the Dell laptop and the Chromebook for all practical purposes.   When I need horsepower, it's inadequate, when I just need to surf the web, it's over-kill.  There never seems to be a time when I actually need it.   So it collects dust until I need to test something on it (and 99% of the time when I do the battery in that super-sexxy Apple mouse needs to be replaced!).


 * So for me, it's a matter of picking the right tool for the job. Most of the time, I use a deskside computer with three large monitors and a really good ergonomic keyboard.  My one less-than-ergonomic peripheral is my MINI Cooper-shaped mouse (it has brake lights that light up when you stop moving the mouse!)...it's actually much more sensitive than most mice and I love the subtle detents in the scroll wheel.


 * SteveBaker (talk) 15:55, 13 January 2015 (UTC)
 * As a counterpoint, I did all the computations an simulations for my PhD. dissertation on a tiny 13" Powerbook laptop. As you know, actual computational complexity isn't always closely related to the complexity of the work. So, while that computer would have choked up a bit on large compile jobs, it was more than enough for my scientific computing needs at the time. The take-home point for the OP is that people have different use cases, and for the foreseeable future computational power will trade off with weight and battery life. Also not all users act rationally, and I suspect many area coffee shop workers like to show off their big, heavy, high powered laptops, even if another machine could suffice :) SemanticMantis (talk) 16:09, 13 January 2015 (UTC)
 * What about engineers? Don't they often require both portability and high powered computers?  Since they use specialist software but also travel a lot to make presentations etc.  So do they have a portable laptop and a high power one? 194.66.246.5 (talk) 16:20, 13 January 2015 (UTC)
 * Engineers are a very diverse group, so I don't think we can talk about all of them at once. Some do a lot of presentations, some never do. Some engineers need computational power, some don't. For example, my brother in law uses a normal modern (thin-ish, light-ish) 15" Dell laptop for his job as an on-site industrial engineer - he runs in-house software but has never mentioned performance issues. But a mechanical engineer using finite element methods to model complex material deformation via partial differential equations might need more computational power. That's the point I was trying to make above - in the modern era, even rather sophisticated modeling and computation can sometimes be relatively computationally inexpensive. Even a very sleek and small modern Macbook Air can do computations in minutes that would have taken days on older desktops. So don't confuse "complicated, hard to understand work" with "work that requires very high performance computers by modern standards"
 * Going the other way, it's really computationally hard to factor large numbers into primes, but conceptually it's very easy. On the other hand, the fast fourier transform requires a lot of mathematical background to understand, but runs very quickly and is used in many engineering applications. SemanticMantis (talk) 16:37, 13 January 2015 (UTC)
 * I typically run 3 or 4 solvers in parallel (they are single threaded) on my vehicle dynamics simulations, but I have found the actual speed of execution of a given job is only vaguely related to the headline numbers of a given computer, things like drive I/O speeds are often as important. I use a laptop for most of my data crunching because I occasionally need to use it in cars and meetings. For a given thread it is slightly faster than my engineering workstation, but that can handle 8 threads at a time, the laptop only 4, and it has much more storage. Greglocock (talk) 19:53, 13 January 2015 (UTC)


 * I'm not sure exactly which laptops you don't think are "portable". Even the big ones are really not that heavy.  Unless you have physical challenges or are planning on going hiking with it, I'm not sure what the problem is.  Cowboy up.
 * I did get a smaller laptop for my last trip to Europe; it is more convenient to carry than my older 17 '' model (which however is much nicer to look at pictures on). So sure, there's a tradeoff, but it's not really "portability".  They're all portable. --Trovatore (talk) 16:45, 13 January 2015 (UTC)
 * Ordi-portable-milouf-img_0999.jpgCompaq_portable.jpg From Portable computer, these images depict computers that are technically portable but many of us would not wish to carry around :) SemanticMantis (talk) 19:33, 13 January 2015 (UTC)


 * There is certainly no "one-size-fits-all" rule here.


 * These days, presentations are often uploaded to the Internet - so when I turn up at some customer's site to do a presentation, I just tell them the URL and have them bring it up on their conference room display screen. So the need to use a computer of any kind is kinda limited.  If I'm concerned that my host might not have an internet-connected TV, I also carry a "chromecast" gizmo - which is no bigger than a memory stick and can be plugged into any TV with an HDMI port...I can use my phone to instruct it to grab video off the Internet and display it.  Using a laptop to do this is definitely overkill.


 * However, if I'm called upon to do a demo of some piece of software, something that can't be done with video, still images and text - then I'll very often have to figure out how to connect my laptop to whatever in-house video system is present - and this is *ALWAYS* a nightmare!


 * Mostly, my computer usage splits into stuff that's on the web (for which my phone or tablet (plus bluetooth keyboard) may just barely suffice - but the HP Chromebook is perfect) and stuff that's heavy programming/documenting work. For the latter, I get massive productivity benefits from having multiple high-resolution screens, so a desktop computer is the only answer.  My large laptop is only useful for those super-rare circumstances where I have a lot of heavy work to do, yet somehow can't be at my desk either at home or in the office...and even then, I increasingly remote-login to a server someplace to do heavy computational stuff.


 * SteveBaker (talk) 19:31, 13 January 2015 (UTC)


 * I used to one of the people with a power laptop to manage complex scientific codes. However, my code outgrew what any laptop can offer, so now I either run on uber workstations (16 cores, 256 GB of RAM) or on computer clusters.  As a result of that transition, I now do most work via remote login, so I no longer need a big laptop.  Hence, a light-weight laptop plus a fast internet connection is now fine.  It really is about the use cases and how much power you need with you to do your work.  Some people want (or need) very powerful laptops and other people have found ways to get things done with less and hence may opt for light-weight, less powerful configurations.  Dragons flight (talk) 19:49, 13 January 2015 (UTC)
 * For me, the nicest thing about large laptops is precisely that they're large. The keyboard is easier to type on; the display is easier to view.  Whether that's worth the extra weight depends on how heavily you're using it, and how far you're planning to walk.
 * Of course at home, I use an external keyboard, mouse, and monitor, so the form factor of the laptop itself doesn't matter much. --Trovatore (talk) 19:54, 13 January 2015 (UTC)

Apollo mission photos left on the moon.
I was reading today that it's more or less certain that all of the US flags that were left on the moon by the Apollo landing crews will have been bleached white by the sun. (Evidently the flags were a last-minute addition to the mission and were bought at a local branch of Sears without consideration of dye stability in intense sunlight!)...I find this kinda ironic...but that's another matter.

Anyway - this made me wonder. Most of the astronauts brought photos of their families or dead friends, etc to leave on the moon as a perpetual memorial to them. It seems likely to me that those too may have been bleached white.

How do the materials in photographs from the 1960's and 70's survive in that kind of intense UV light? At least a couple of the photos seem to be color pictures...and I know that color photos I have from the 1960's have faded quite a bit - despite being kept mostly in the dark. It doesn't look like the pictures were in any way special...like not special dyes used to make them or anything.

Did all of those treasured pictures wind up as white cardboard squares?

SteveBaker (talk) 15:29, 13 January 2015 (UTC)


 * I'd think yes, they would be bleached white if left exposed to the Sun. But perhaps they buried them under a layer of Moon dust, or even if not intentionally done, the dust generated when the lander took off might have coated them with a thick enough layer to block UV. StuRat (talk) 15:34, 13 January 2015 (UTC)
 * Ignoring launch events "It would take 1,000 years for a layer of moon dust about a millimeter (0.04 inches) thick to accumulate" . I'm not sure how much the launch would have generated, but unless that was enough by itself the natural dusting process wouldn't provide enough protection. SemanticMantis (talk) 15:50, 13 January 2015 (UTC)


 * Have you done any research on the insolation of the moon across the spectrum? It might be useful to be able to express irradiation on the moon in terms of how much more or less light hits the surface at each wavelength, compared to the Earth. The other thing would be to narrow down what type of printing technology was likely to have been used. E.g. a polaroid may well fade much more quickly than a Kodachrome print. Also they may have put them in protective sleeves, as mentioned at Photograph. The article mentions atmospheric protection, but also "Polyester contains a benzene ring that absorbs UV light" (https://en.wikipedia.org/wiki/Sun_protective_clothing) For Earth-bound photos, much of the degradation is due to reactions with the atmosphere (e.g. humidity), in addition to light. Obviously the moon has less humidity fluctuation so that might help to counteract any increase in UV exposure. SemanticMantis (talk) 15:50, 13 January 2015 (UTC)
 * Kodachrome was only a transparency film. Kodacolor (still photography) is a negative film which is used to produce prints. Edison (talk) 16:10, 13 January 2015 (UTC)
 * Oops, thanks! I wanted to link to a WP article about the various methods of making prints from film but all I can see at present is the large List_of_photographic_processes. SemanticMantis (talk) 16:13, 13 January 2015 (UTC)

Images on Voyager Golden Record
What is the image format used to encode the black-and-white and color images on the Voyager Golden Record? 20.137.2.50 (talk) 17:12, 13 January 2015 (UTC)


 * See Voyager Golden Record. Rojomoke (talk) 17:46, 13 January 2015 (UTC)


 * It's not really an "image format" in the sense of "JPEG" or something. It's a monochrome raster image (such as would be transmitted to a TV set back in the days of black and white analog television) - but for some reason they scaned the images vertically instead of horizontally. So the horizontal resolution of the images are 512 lines but the vertical resolution is determined only by the quality of the recording and playback equipment - but probably less than 512 "pixels" per scanline because that explains why they'd use vertical scanning to improve the overall resolution of non-square images.  The amplitude of the wiggles in the grooves of the record are the brightness of the image.   It's about as simple as it could possibly be, given the (essentially analog) standards of the day.   They even included a stylus with the record to allow the disk to be read more easily.  Color images are encoded with three consecutive images in red, green and blue. SteveBaker (talk) 19:17, 13 January 2015 (UTC)

Dumb questions? Science at school never explained certain stuff to me.
1) Why do we count seconds and minutes up 60. Why not have 100 seconds in a minute. And 100 minutes in an hour. It would make time math so much more simple. 2400 minutes in a day.

2) And also, why do helicopters keep their relative position whilst hovering. Since the earth is spinning, shouldn't the ground be moving underneath it. Likewise, what if you were travelling in a plane at the speed of earths rotation. Shouldn't this enable you to hover and remain in once place.

3) And also, what if I was travelling 1mph below the speed of sound and a threw myself forward 2 mph. Would that cause a sonic boom, would I be technically travelling faster than the speed of sound. Again likewise, isn't that cute, sexy cabin stewardess pushing that trolley up the aisle moving faster than the plane she's travelling on. Wow. — Preceding unsigned comment added by 82.19.76.217 (talk) 17:26, 13 January 2015 (UTC)


 * So, this is what happens to the youth of a country when they don't have college football championships? See hour, minute, second, flight in air versus orbit in vacuum, and relativity and sonic boom in light of relativity. μηδείς (talk) 18:37, 13 January 2015 (UTC)


 * (I added numbers):


 * 1) The base 60 system is left over, I believe, from Babylonian times. They wanted a number that's divisible by a lot of integers, and 60 is divisible by every integer up to 6, while 100 isn't even divisible by 3.  This was before fractions or decimals were much used, so they liked keeping things as integers, whenever possible.  So, if you had 6 people taking shifts using pedals to drive a pottery wheel, each would have a 10 minute shift, nice and easy.  During the French Revolution, they tried to introduce metric time, but it was just too different.


 * 2) The helicopter and plane all move by displacing air, so their base speed is that of the air, and then they either add or subtract from that speed. See air speed and ground speed, which can vary dramatically, say if the plane is in a jet stream.  The air moves with the Earth, ignoring wind, because the same forces which started the Earth spinning also did the same thing to the atmosphere, and friction with the ground ensures that the atmosphere moves more or less at the same speed as the rest of the Earth.


 * 3) A sonic boom is caused by the relative velocity of two objects, not the absolute speed (if there is such a thing). So, you won't create a sonic boom on the plane, but I suppose if you were crazy enough to have an open window at that speed and yelled as you ran down the aisle, you might indeed create a very minor sonic boom to observers on the ground.  Of course, you won't make nearly as much noise as jet engines, so they likely won't even hear it. StuRat (talk) 18:41, 13 January 2015 (UTC)


 * It is probably based on the Egyptian calendar actually since a year was 360 days (plus 5 extra days). Months were always 30 days and weeks were 10 days. I would think the helicopter question is mostly a matter of inertia. When a helicopter takes off it retains its inertia that it had while grounded. It moves by changes its inertia relative to the planet. Otherwise its natural state should be to move in the same direction as the planet (i.e. hover). Taking off doesn't reset its inertia to zero and cause the planet to rotate away from it.David Bradley I (talk) 19:06, 13 January 2015 (UTC)


 * We have 60 seconds to a minute, 60 minutes to an hour, and 24 hours to a day because we inherit these measures from older civilisations. Many, in particular the Babylonian civilisation, divided things into 60 because it is a particularly easy number to divide into smaller parts. Thus, 60/2 is 30, 60/3 is 20, 60/4 is 15, 60/5 is 12, and 60/6 is 10. Also, 60/12 is 5. 60 is the smallest number that when divided by 2, 3, 4, 5, 6, 10 and 12 gives a whole number answer. This is very useful if you don't have a calculator to help with your arithmetic. We have 24 hours in a day because originally the day and the night were each divided into 12 hours (24=12+12). 12 also has lots of divisors (2, 3, 4, 6, 12), and so is again a helpful number when you're doing arithmetic without a calculator, particularly when you're doing business that has to be equally split between 2, 3 or 4 people.
 * So our measures for time are really the result of people in history choosing numbers that made it easy for them to do their sums. If we were going to design a new time measurement system today, we might well choose something different. RomanSpa (talk) 18:55, 13 January 2015 (UTC)

(ec)
 * Why 60's? The Egyptians Babylonians liked to use numbers that are effectively in base 60 - and from then we get 60 minutes in an hour, 60 seconds in a minute, 60 degrees in an equilateral triangle and so forth.  60 is actually a nice number to choose because it divides evenly by 2,3,4,5,6,10,12,15,20 and 30.  100 isn't so nice: 2,4,5,10,20,25 and 50.
 * The air more or less follows the rotation of the earth because of friction between it and the ground - helicopters remain stationary compared to the air (not really the ground).
 * Yes, if you could do that outside the airplane, that would cause a sonic boom. Yes, you would be travelling faster than sound.  However, the speed of sound is (just like the helicopter) measured relative to the speed of the air.  So inside the plane, the air is moving at the same speed as you are and the speed of the trolley is only a couple of mph faster than the air...so the speed of sound isn't broken.  If you put the cart on the wing of a plane that's flying 1mph below the speed of sound and pushed it forwards at 2mph - it would break the sound barrier...boom...etc.
 * SteveBaker (talk) 19:02, 13 January 2015 (UTC)


 * Isn't a sonic boom caused by the velocity of the source measured relative to the observer, not the air ? StuRat (talk) 19:14, 13 January 2015 (UTC)


 * DF has the correct answer and refs below. But perhaps you got confused with the doppler effect? Interestingly enough the common illustrations like those used in our article are vaguely similar to the illustrations for sonic booms. SemanticMantis (talk) 19:59, 13 January 2015 (UTC)


 * Aren't they basically the same thing ? That is, the Doppler effect describes waves being compressed in time or stretch out, due to the relative speeds of the source and observer.  If they are compressed to a single wave, that's a sonic boom. StuRat (talk) 05:55, 14 January 2015 (UTC)


 * No, a shock is a very different sort of wave - it's mathematically modeled as a discontinuity, and they have special rules for propagation, energy dissipation, etc. In contrast, the doppler effect is simply the interaction of relative motion with classical sound waves. The doppler effect is dependent on the relative velocities of the emitter and the receiver, while the shock wave only depends on the speed of sound in the medium. Now, in the real life case of listening to airplanes, one will hear a doppler effect for subsonic planes, this is pretty obvious if you've ever stood still while a crop duster flies low over head. In the case of a supersonic plane, you don't hear anything until the shock reaches you, but then (I think) you will hear the pitch shifted down as the plane recedes (compared to someone moving in the same direction as the plane). SemanticMantis (talk) 15:59, 14 January 2015 (UTC)


 * Hmmm....I don't see how. The sonic boom has to travel from A to B (eg from a Concorde airliner to a car window down on the ground that shatters from the sonic boom)...the intervening air can't "know" how fast the car is moving - either the energy is transmitted or it isn't - and when that energy arrives at the observer, it still needs to be dissipated by shattering the window.   If what you say were true then aircraft travelling at supersonic speeds would be suffering sonic booms from buildings on the ground...and how would the air near to the buildings 'know' to transmit the energy up to an aircraft that may or may not be above them?  I think you must be incorrect.
 * SteveBaker (talk) 19:38, 13 January 2015 (UTC)


 * Buildings don't make much sound to cause a sonic boom. I'd expect that if they did, passing airplanes at mach 1 would indeed hear sonic booms. StuRat (talk) 05:51, 14 January 2015 (UTC)


 * No no no, not at all. The only way you'd get sonic booms from a building is if the wind hit Mach 1.  (And at that point you don't have buildings anymore.) --Trovatore (talk) 17:11, 14 January 2015 (UTC)


 * OK, I think I see the difference. The sound from the stationary object would only hit the fast moving object all at once if it was moving infinitely fast toward the source.  It would get louder, though, if approached at high speed, including the speed of sound.  Since a sonic boom never has exactly all the sound compressed into an instant, I wonder how the energy of the two compare, at different speeds. StuRat (talk) 18:11, 14 January 2015 (UTC)


 * The "sound from the object" is not the point. See the longish explanation below. --Trovatore (talk) 19:53, 14 January 2015 (UTC)

I think I see where Stu is going wrong here, and while it's definitely not my field, I think I know enough to clear this up in general terms. Here's my effort. Stu seems to think that sonic booms come from the noise made by the booming object, Doppler-shifted past infinity. That is not exactly right. Suppose you're flying along at a modest airspeed, say 100 mph or so. Consider a chunk of air just a little in front of your wing's leading edge. By the time the wing gets to where that chunk is, the chunk will have to have moved out of the way, right? Some goes over the wing, some goes under, complicated stuff happens to other parts of it, but in any case it's not where it was. But how did it know the wing was coming? That's because the wing set up a compression wave propagating forward, which moved the chunk of air out of the way. That wave moves at the speed of sound. Now suppose your plane is supersonic, and consider the same chunk of air just forward of the wing. Now the compression wave can't get there in time! The wing is just at the chunk of air, with no "warning", as it were. The piece of air has to just suddenly split in two. That's where you get your discontinuity, your shockwave, your sonic boom. As I say, not my field, and I don't claim this exposition to be exact, but I think this is roughly the idea. --Trovatore (talk) 18:06, 14 January 2015 (UTC)


 * Note: The structure of responses might be disrupted by my outdent above &mdash; for future reference, I think Dragons flight is responding to SteveBaker. --Trovatore (talk) 18:08, 14 January 2015 (UTC)
 * No, a sonic boom occurs when an object is traveling through a medium (e.g. air) faster than the speed of sound in the medium. The only things that matter are the relative velocity of the object to the media and the local speed of sound.  Observers don't enter into it.  Either a shockwave forms, or it doesn't.  It doesn't matter if someone is there to hear it.  Dragons flight (talk) 19:54, 13 January 2015 (UTC)


 * Right, but Steve said it's the speed of the source relative to the speed of the medium, which isn't quite the same as it being the speed of the source relative to the speed of sound in that medium. StuRat (talk) 05:51, 14 January 2015 (UTC)


 * Regarding the divisions of time, we have a whole article about the Sexagesimal system. DMacks (talk) 19:16, 13 January 2015 (UTC)


 * The air more or less follows the rotation of the earth because of friction between it and the ground .. Actually I do not believe that is correct. Sturat AND stevebaker both said this, I'm a little surprised.. Is this a common misconception or are they just over simplifying things? This makes it sound like the earth is or was spinning faster than the atmosphere, or that the atmosphere somehow "lags" behind the earth for some reason. The fact is, the atmosphere has mass, just like the earth. The earth is rotating freely, there is no extra force keeping the earth spinning that has to somehow transfer to the atmosphere. In the earth's rotational frame of reference, the atmosphere is perfectly stationary, just like the water, just like a ball you put on a flat surface and just like us. I do not believe friction plays any part in it. Vespine (talk) 22:00, 13 January 2015 (UTC)


 * That would be true if there was no north/south airflow - but coriolis forces mean that there is lateral flow due to the rotation of the earth and that velocity has to be removed somehow. SteveBaker (talk) 03:15, 14 January 2015 (UTC)


 * And I did say they started out with the same rotation, but if not for friction, the atmosphere wouldn't necessarily maintain the same rotation speed as the Earth indefinitely. Look at the Sun, which rotates at different speeds at the equator and the poles, due to low friction relative to the other forces at play. StuRat (talk) 05:06, 14 January 2015 (UTC)


 * Curious, instead of admitting your mistake, you are both attempting to rationalize it. Either of you care to provide a citation for your claims? I believe you are both incorrect. Friction does NOT play any significant part in the atmosphere rotating along with the earth. It's newtons 1st law. What force is the friction counteracting? Coriolis effect is a frame of reference effect, textbook models assume no friction (search our article for "friction"). And sturat, we're not looking at the sun, we're looking at the earth, the sun requires plasma thermodynamics to explain, the earth doesn't. The atmosphere spins with the earth because it has mass just like the earth does and no additional force is acting on it to slow it down which "friction" would have to overcome. Surely if the earth was exerting ANY frictional force on the atmosphere, the atmosphere close to the earth would be "spinning" slower than the atmosphere at the top, which I do not believe is the case. Vespine (talk) 23:12, 14 January 2015 (UTC)


 * No, I think Steve and Stu are correct here. If there were no friction between the Earth and the atmosphere, their relative angular speed would drift over time, as the atmosphere was perturbed by various external torques.  --Trovatore (talk) 01:40, 15 January 2015 (UTC)


 * If you don't like the Sun, look at Jupiter, where the friction is rather minimal, relative to other forces. There you get bands of atmosphere moving over 100 m/s, constantly.  And the atmosphere of Earth does move more slowly close to the surface than it does aloft.  Ever hear of jet streams ? StuRat (talk) 02:55, 15 January 2015 (UTC)


 * Now come on, stop trying to weasel out of it, citations please? Perturbations? We’re talking about general principles, please provide ANY citation that shows that friction from the earth has an effect on the movement on the atmosphere caused by the rotation of the planet. And NO Saturn is NOT good enough either, it is a gas giant, a completely different kind of planet than the earth. It is in effect a giant ball of gas spinning, not a giant ball of rock covered with a tiny film of an atmosphere. And while we’re at it sturat, which way do jet streams travel? And which way does the earth rotate? Oh snap, if the earth WAS causing friction, you'd expect them to be opposite wouldn't you? Friction has nothing do with the formation of jet streams, please feel free to read the cause section, which even includes a word on OTHER PLANETS where planetary rotation or surface friction is STILL not mentioned as a cause or even a factor in the formation of jet streams. The question was: why does the atmosphere not move in relation to the earth, the answer is because the atmosphere has mass and just as much relative momentum as the earth, as there are no external forces speeding it up or slowing it down (over sub geologic timescales), it will keep rotating at the same rate, friction plays no appreciable part in this. Vespine (talk) 04:43, 15 January 2015 (UTC)


 * I don't have a citation handy, but I haven't noticed you throwing them around either. Vespine, I think you're understanding "friction" to mean "the atmosphere would naturally stand still if it weren't for the Earth dragging it along".
 * But that isn't the argument. Sure, the atmosphere set in (rotational) motion will tend to remain in motion.  But even if it's at some point synched to the Earth, why do you expect it to stay that way?  There are always external forces.  There's radiation pressure.  There's solar wind.  There are tidal forces.
 * The rotational acceleration that any one of these imparts to the atmosphere is probably small. They're probably reasonably random and tend to balance out, more or less.  And to the extent that the net effect is in one direction in January, it may well be in the opposite direction in July.
 * But do you really expect them to balance out exactly? That would need explanation, I think.  And if they don't balance out exactly, well then, over time, the effect is going to build up.
 * So how come we don't see a secular increase in wind speed over time, if it's not for friction? --Trovatore (talk) 05:24, 15 January 2015 (UTC)


 * No, jet streams aren't caused by friction with the ground, they are what happens to the atmosphere far from the frictional effect of the surface. It does it's own thing.  And the whole reason the atmosphere of gas giants and stars behaves differently is because friction is negligible.  We should probably discuss how the atmosphere of Earth would behave differently, were there no friction with the ground.  Look at how one atmospheric phenomenon, hurricanes, behave now.  They follow the prevailing wind direction, until they hit a continent.  Then they either are deflected back out to sea, or they die.  If there were no continents to stop them, they would likely continue in bands parallel to the equator for 6 months at a time, until the season changed.  If the Earth wasn't tilted relative to the ecliptic, you might even get permanent hurricanes, like the gas giants have. StuRat (talk) 05:15, 15 January 2015 (UTC)


 * Here's a map of prevailing wind directions in January: . As you can see, they set up in bands parallel to the equator, just like on Jupiter, until they hit a continent, then the bands are messed up. StuRat (talk) 05:22, 15 January 2015 (UTC)


 * I have provided several references, please feel free to point out where any of them mention friction as a force that plays a part in keeping the atmosphere in place. Let me put it this way, back to first principles: say you are standing in a train carriage moving at a constant velocity, what force stops you moving to the front or the back of the carriage? It's not friction, the answer is that no force is required to keep you from moving to the front or the back of the train. You could be on a frictionless surface, like a skateboard and unless the train accelerates you would remain in place. It's exactly the same question, it's about general principles. When you stand on a skateboard parallel to the equator on earth, is it friction stopping you from accelerating in a east west direction? That's nonsense. Vespine (talk) 06:51, 15 January 2015 (UTC)


 * You haven't provided anything remotely close to a reference for the claim that friction is not involved.
 * Again, you're misunderstanding the point. No one in this discussion has ever said that friction what keeps the atmosphere from standing still while the Earth rotates (which is what you seem to be implying with the "skateboard" example).  I don't see any evidence that Steve or Stu ever thought that.
 * As for the "train" example, in practice, it absolutely 100% is friction that keeps you in place in your train seat. If there were not friction, you would respond to external forces and start to drift.  There are always external forces; you can ignore them in the same sense you can assume a spherical cow. --Trovatore (talk) 07:13, 15 January 2015 (UTC)


 * MY source showing prevailing wind directions is excellent evidence for the effect of friction (with the ground) on the motion of the atmosphere. Perhaps you are having trouble with the word "friction".  This includes things like running into mountains, which saps the wind of it's energy and/or redirects it in a new direction.  Trees also have an effect.  Flat, smooth ground (like obsidian) would have the least effect, even less than the oceans. StuRat (talk) 17:54, 15 January 2015 (UTC)

Babylonian mathematics
The use of base 60 is not Egyptian. The Egyptians used a non-place-value system of numerals, similar to Roman numerals, as did many ancient peoples. The Babylonians did use the sexagesimal system, which was a place-value system. It had great computational power, as do Arabic numerals, but its use required memorizing an extremely large addition table and an extremely large multiplication table. It, like base-ten Arabic numerals, did allow fractional computation to any desired amount of accuracy, by just computing the multiplication or division to the required number of sexagesimal (or decimal) places. In classical antiquity Babylonian arithmetic was used for astronomy and astrology, and not for other purposes, because it was difficult (but precise). Why the Babylonians used base 60, rather than base 10 or base 20, is a historical mystery. Robert McClenon (talk) 21:24, 13 January 2015 (UTC)


 * My error - I'm sorry...corrected, above. SteveBaker (talk) 03:15, 14 January 2015 (UTC)


 * Robert says that the reason for adoption of sexagesimal is a mystery, however the Wikipedia article implies it is due to the ability to count using one hand and the various finger bones.  This is what I had recently read also,  do the sources in the article support this? 203.109.158.201 (talk) 23:37, 15 January 2015 (UTC)

Helicopter question
The helicopter obeys Newton's first law of motion "When viewed in an inertial reference frame, an object either remains at rest or continues to move at a constant velocity, unless acted upon by an external force". If that wasn't the case if you jumped off the ground at the equator the Earth would move under you at 465 meters/second and you would end up a long way from where you started. So because you are already moving at a velocity of 465 meters/second when you jump, and there is no "external force" to slow you down, you carry on at the same velocity as the Earth and land in the same spot. But don't worry, you're not dumb. It took a genius like Isaac Newton to work all this out. Richerman   (talk) 22:00, 13 January 2015 (UTC)


 * Well, once you ignore Newton's laws, anything could happen, but there's no reason to assume he'd hover above the ground pushing air out of the way at orbital speed, why not have him fly off to space in a slowly expanding spiral, staying above the launch point, and moving upward at his original launch velocity? μηδείς (talk) 22:54, 13 January 2015 (UTC)


 * Because the person who asked the question appears to be asking "why is it that when something leaves the ground that the spinning Earth doesn't move beneath it?". The fact that they used a helicopter as an example is not really relevant to what they are asking and I've tried to keep the answer as simple as possible. Richerman    (talk) 23:38, 13 January 2015 (UTC)


 * I was looking at it the other way. The air, etc., doesn't move along independently of the Earth's surface either; i.e., get left behind.  So maybe everything is either pushed by the wind, or inherently stays in its "place" which would either imply the air is keeping you stuck to the ground due to its pressure the Casimir Effect on the bottom of your feet, and that if you lose contact you will fly upward, not so fast, but in an ever widening spiral.  There's a Latin phrase for the fact that assuming any contradiction implies all contradictions, so if we accept that one law of nature can be violated, we can accept the violation of all of them. μηδείς (talk) 02:14, 14 January 2015 (UTC)


 * We don't need Latin phrases or the Casimir effect to account for something that Newton's first law already explains perfectly well. AndyTheGrump (talk) 03:11, 14 January 2015 (UTC)


 * No, we don't. No one said we did. μηδείς (talk) 18:17, 14 January 2015 (UTC)


 * This kind of question is a rephrasing of the old joke about a truck full of birds and how they have to keep them flying in order to keep the truck's weight down. ←Baseball Bugs What's up, Doc? carrots→ 20:13, 14 January 2015 (UTC)

Is it safe to add lactobacillus acidophilus to gazpacho and would it prevent or slow fermentation?
I guess this all comes down to how well it could compete against yeast and would the sugars available in gazpacho (mostly tomatoes) be adequate for feeding it? An ancillary question is how active is lactobacillus acidophilus in producing gases? The main problem with the fermentation is the gas produced and so it would make little sense to replace one gas-producing organism with another. — Preceding unsigned comment added by David Bradley I (talk • contribs) 18:48, 13 January 2015 (UTC)
 * As far as I know lactobacillus acidophilus do not produce gas, they produce lactic acid. They do not compete with yeast, they actually work well together, see: SCOBY. Ariel. (talk) 11:21, 14 January 2015 (UTC)


 * Thanks for reminding me about SCOBY. I'd been reading a study ( http://www.ncbi.nlm.nih.gov/pubmed/7898374 ) which suggested to me that it might be useful in inhibiting fermentation. David Bradley I (talk) 18:59, 14 January 2015 (UTC)
 * SCOBY is a fermenting agent. Kombucha, ginger beer, vinegar, all of these can be produced via fermentation with SCOBY. So I don't see how you would think it inhibits fermentation. Perhaps you mean that SCOBY might ferment sugars more slowly than a pure yeast? SemanticMantis (talk) 21:28, 14 January 2015 (UTC)


 * I thought it inhibited fermentation because that's what the study I linked to seems to indicate. Perhaps it depends on the environment. David Bradley I (talk) 23:17, 14 January 2015 (UTC)

How much Phytoestrogens, on average, we have on 100g of cooked soybeans?
Thx. Ben-Natan (talk) 21:05, 13 January 2015 (UTC)


 * This source says 40mg per 1/2 cup of soy beans, 165mg per 3.5 oz of roasted soy beans . It appears to be a fairly reliable source but it does not itself cite sources, so better-cited sources will still be helpful. SemanticMantis (talk) 22:16, 13 January 2015 (UTC)


 * "cocked soybeans" ? StuRat (talk) 23:19, 13 January 2015 (UTC)


 * Fixed... Cooked... ! Ben-Natan (talk) 09:25, 14 January 2015 (UTC)

Female ejaculate
So I read over here that female ejaculate is actually just urine. However from what I read from other people and what I've seen in pornos, it looks more clear than normal urine and doesn't have the same offensive odor. I also heard that when it dries up it leaves behind a whitish residue as opposed to a yellow residue. My question is, is female ejaculate safe to consume unlike normal urine? Mind you, this is not a medical question, I'm just curious. 69.121.131.137 (talk) 22:51, 13 January 2015 (UTC)


 * Always try a search for an article! Like female ejaculation. :) Wnt (talk) 23:07, 13 January 2015 (UTC)


 * Although I don't speak from personal experience, your suggestion that normal urine is not "safe to consume" seems to be false, at least if it's from a healthy person, as you can see from our article on urophagia (the consumption of urine). RomanSpa (talk) 00:54, 14 January 2015 (UTC)


 * That would explain why Aussies and Kiwis are always "taking the piss". :-) StuRat (talk) 04:59, 14 January 2015 (UTC)


 * Bear in mind as our article sort of says, what's shown in porn may not be particularly similar to what most people experience in real life, unless they're trying to emulate porn. Or to put it a different way, even though there could be female ejaculation that is distinct from urination, it doesn't mean that all, or even a majority of that shown in porn as "female ejaculation" is not simply urination or even simply some fluid held in the vagina and released at the right time . Also, in both females and males (I presume you have partially experienced this yourself), the colour of urine can vary significantly depending on how much water has recently been drunk (and whether the water has been lost via other means like sweating). So "more clear than normal urine" is pretty meaningless, as urine can be fairly clear when dilute (see e.g. ). As that indicates, you can also get some weird colours due to certain foods and other dietary products, but I don't know if this is particularly useful for most porn purposes (in particular, I'm not sure if it's easy to get a milky colour without a bladder infection). Similarly, unless you are referring to Smell-O-Vision porn or are you a performer, camera operator, directory or someone else on porn sets, I presume you have no idea how the stuff on porn sets smells. (And realisticly even if you did have some sort of scent simulator and porn made for that purpose, they're not going to give the unpleasant smells unless it's for a specific market that wants that.) The smell can also be strongly influenced by diet, e.g. garlic, onion, asparagus and petai are foods fairly known for influencing the smell of urine (and often other bodily odours). I'm not sure that people find the smell of diet urine in general that offensive although they probably don't find it pleasant and can probably recognise the odour if they smell carefully enough in a suitable environment. People's perceptions of stuff is also often influenced by sexual activity. Nil Einne (talk) 04:50, 14 January 2015 (UTC)


 * I cannot help but be amazed at the range of themes this OP is curious about. Richard Avery (talk) 07:57, 14 January 2015 (UTC)

How do household appliance water tanks work?
I've had a few small humidifiers and they have all had a similar water delivery system. A removable water tank with a sealable opening (used to refill the tank with water from a faucet) and an opening at the bottom to allow the water to empty from the tank into the humidifier itself. It appears that the opening at the bottom has a spring such that when the spring is compressed, water will exit and when the spring is unaltered, the water tank is sealed closed. Somehow, the humidifier must be able to let in an appropriate amount of water from the tank into the humidifier via this spring opening. However, if it lets in too much water, the humidifier will leak, and too little water will interfere with humidifying a room. I've never seen any apparatus or anything that appears to somehow press the water tanks spring in some sort of regulated fashion.

While I know this description is not perfect, I'm wondering if it is enough for anyone to explain or find references that explain how the humidifier is able to let in the appropriate amount of water into the tank, especially given the absence of any noticeable mechanism on the humidifier that performs this job. — Preceding unsigned comment added by 68.10.236.226 (talk) 22:55, 13 January 2015 (UTC)
 * The ones I've seen, the humidifier body has a prong that pushes up against the spring-loaded valve on the bottom of the tank, letting water into a pool in the humidifier body. As the pool fills, air bubbles up from the valve (like dumping a bottle upside down rather than pouring it out in an even flow). Eventually the water-level of the pool reaches and covers the valve, so no more air can bubble back up into the tank, so no more water can pour out (it creates a partial vacuum in the air-space in the tank). It's the same principle as a barometer. You can do the same thing if you put the mouth of a bottle you are dumping out into a glass or other container that already contains a high water-level. As the humidifier uses up its pool, the water-level there drops, allowing more air to bubble up into the tank, allowing more water to drain into the pool, until the level again rises to cover the valve. DMacks (talk) 23:24, 13 January 2015 (UTC)
 * Thanks! I learned something new today! 68.10.236.226 (talk) 22:12, 14 January 2015 (UTC)

Lorentz Contraction at near light and faster than light speeds
This question is meant to be a kind of semi-related addendum to this question about Lorentz Transformations.

I am having some trouble visualizing this concept, so I will start my question with an example. For the sake of clarity, the descriptions I provide throughout this question will contain, perhaps, more detail than necessary. Let's say there are only two objects in the universe: the Earth, and a spaceship beside the Earth traveling in a line perpendicular to the radius. Let's also say for the moment that there is no warping of spacetime due to the Earth's gravity.

Speeds Near c
For relativistic speeds, the ship would need to be traveling at, say 0.925c. 1) At this speed, Lorentz Contraction dictates that Earth would contract along the y-axis and appear more like a watermelon lying on its side, correct? 2) Is this because traveling closer to c means that more horizontal beams of light (from the Earth to the ship, along the x-axis) hit your eye than normal? 3) Wouldn't this also make the squashed Earth appear brighter since the eye is receiving more light-per-second than normal?

This is all I am writing for now, though I do have more questions. To those who respond, please be sure to sign your replies. Thanks, Loonybin0 (talk) 23:02, 13 January 2015 (UTC)


 * A spherical object will appear circular to anyone traveling at any speed, though surface features like continents will be distorted within the bounding circle. It will also appear closer to your direction of motion than it would if you were stationary (relativistic aberration) and it will be smaller and blueshifted and brighter (if ahead) or larger and redshifted and dimmer (if behind). Can You See the Lorentz–Fitzgerald Contraction? from the Usenet Physics FAQ has some more information. -- BenRG (talk) 00:10, 14 January 2015 (UTC)
 * This video shows these effects pretty well. Starting at 5:08 they show rapid travel around the Earth (but with Doppler and brightness effects "turned off" so only the aberration is seen). -- BenRG (talk) 00:21, 14 January 2015 (UTC)


 * I don't understand this answer, for you say spherical objects "will appear circular" in all frames but I'm not so sure why that would be the case. [Appearances can be deceiving though.] Consider the counter-example of ions. From our referenced article on length contraction: "Heavy ions that are spherical when at rest should assume the form of "pancakes" or flat disks when traveling nearly at the speed of light. And in fact, the results obtained from particle collisions can only be explained when the increased nucleon density due to length contraction is considered." Also consider that a very vast spherical shell of relatively stationary stars is a spacial geometrical object that becomes measurably contracted in the direction of travel of the star-ship and thus less spherical. To be consistent, because the spacial scale of objects does not matter when plugging away at the Lorentz transforms, for we can talk about electron shells, planets or star systems, the Earth would also have to be measurably contracted as a thinner spheroidal object. This is what I understand to be predicted although the all important scientific measurement of large scale frame-dependent differences of length contraction has not yet been measured. -Modocc (talk) 03:15, 14 January 2015 (UTC)


 * Length contraction is a real thing. It's closely analogous geometrically to the fact that a diagonal slice through a cylinder (or a dowel, to be more concrete) is an ellipse rather than a circle. A moving object is length contracted at a particular time because "at a particular time" means the intersection of its worldline with a plane of simultaneity, and if that plane is slanted relative to the worldline (i.e. if the object is moving) then the slice is not a circle. That's a true statement about abstract spacetime geometry, but it's not as important as many people think, because planes of simultaneity almost never have any physical significance. For starters, they don't tell you what you see. What you see is the intersection of the worldline with your past light cone, not with a plane.


 * One way of understanding why you always see spheres as circles is that the effect of relativistic aberration turns out to be a Möbius transformation, and Möbius transformations take circles to circles. In fact there's a natural one-to-one correspondence between Möbius transformations and Lorentz transformations that's given by the aberration behavior (see Lorentz group and the next section, "Appearance of the night sky"). I don't really understand geometrically why Lorentz transformations should behave that way, though.. -- BenRG (talk) 08:09, 14 January 2015 (UTC)


 * You didn't include the Sun so it will be quite dark. :-) But the light received at right angles will be blueshifted because of the transverse Doppler effect. Also, if the light from the surface is radiating in all directions, its intensity at any point is then inversely proportional to the distance squared. The Earth is supposed to be contracted like a watermelon too, but as BenRG points out above, optically, it will appear not to be. -Modocc (talk) 07:22, 14 January 2015 (UTC)