Wikipedia:Reference desk/Archives/Science/2011 December 3

= December 3 =

Flame without combustion
Can you have flame without combustion? Like lets say a meteor falls from the sky and burns up, or a slug of metal is fired from a railgun and creates a plume of flame, is there a combustion reaction going on in both cases? ScienceApe (talk) 02:07, 3 December 2011 (UTC)
 * In these cases, there are visible flames, but not due to combustion -- these are due to the air being heated to white heat by the friction (and shock waves) from the rapidly moving object, which causes the air to emit black body radiation in the visible spectrum. 67.169.177.176 (talk) 02:52, 3 December 2011 (UTC)
 * Hmmm, air is pretty transparent, so it's hard for it to emit black-body radiation. As can be visualized with the upper part of a gas flame and a few grains of lithium chloride or other such coloring agent, air tends to be much more pyrotechnic with an added ingredient.  Since a meteor itself releases material as it passes through the atmosphere, you may indeed in some sense be seeing it "burn up" even if combustion is not the source, in the sense that the released meteor material is what actually glows. Wnt (talk) 20:54, 7 December 2011 (UTC)
 * This question is more about language than science - it depends on the meaning of the word "flame". Roger (talk) 14:02, 3 December 2011 (UTC)

Titan lakes
Are the lakes of Titan (such as Ligeia Mare) drinkable? If it was on Earth, could aquatic life live in it? If not, is it possible that life could adapt to the conditions in the lake? 64.229.180.189 (talk) 02:12, 3 December 2011 (UTC)


 * As the article on Ligeia Mare says, it is composed of liquid hydrocarbons, primarily methane, not water. So, they are not drinkable. Besides, it is extremely cold on Titan (mean surface temperature (−179 °C / −290 °F).--Itinerant1 (talk) 02:16, 3 December 2011 (UTC)


 * Earth life would not thrive in such a lake and would be snap frozen, as it is close to the temperature of liquid nitrogen. That does not rule out some exotic other form of life that uses hydrocarbons as a solvent.  But one issue is that not many substances dissolve in liquid methane, unlike water which can dissolve many interesting substances and support their chemistry. Graeme Bartlett (talk) 03:16, 3 December 2011 (UTC)


 * I can't think of that many places where even sci-fi authors have dared to speculate about creatures made of molten rock rising up from the magma to show themselves to an astonished surface world - on film I can only think of the original Star Trek, actually. But from the perspective of some hypothetical Titan dweller, that's just what we are, because water there is unambiguously a kind of rock, except perhaps in a "magma" deep below the surface. Wnt (talk) 14:04, 3 December 2011 (UTC)

Is Wikipedia a conscious entity?
Like our brain, the Wikipedia servers contain information about the external world. Also just like the brain has an internal model about its own body, Wikipedia contains information about the state of its system, like a file of topic banned editors, discussions at AN/I about problems on Wikipedia itself, etc. etc.

If I were to accidentally touch a hot object, that would trigger a reflex leading to me withdrawing my hand. If an IP were to vandalize an article, there is also a prompt reaction. You can then ask if the Wikipedia system (Wikipeida servers plus all active editors) is an entity that feels pain if it is perturbed in the direction of a non-ideal state. The reaction could be described as a reflex, but then there follows a modification of the internal sate of the system like the IP being warned. That is similar to how after touching a hot object, your hand doesn't feel the same as it was before, the brain flags it has having violated the rule against toughing hot things.

So, it seems to me that Wikipedia may be a conscious entity. Count Iblis (talk) 02:41, 3 December 2011 (UTC)


 * Let's start off by black boxing the issue of "what is consciousness". Plants can respond to stimuli; that doesn't make them conscious. But somewhere between a plant and a human being, consciousness emerges. Let's take that as a given, because doing so saves us some time, and avoids the question whether you or I are "really" conscious at all, which, while a somewhat interesting idea, is unnecessary to engage with for the purposes of this discussion. Let's pretend we agree that all normally developed humans not currently in coma states are more or less "conscious."
 * The problem with asserting that Wikipedia is conscious is that its consciousness, or appearance of consciousness, is entirely the product of other certifiably conscious beings. This is different than, say, you and me, because our cells are, as far as we can tell, not individually conscious. Wikipedia is only as conscious as its users. Hook up a bunch of cats to Wikipedia, and you get no interesting phenomena, other than the occasional accidental click. Hook an AI bot up to Wikipedia, and you can probably do pretty well (our bots are clever enough), but nothing more than menial labor (reverting obvious vandalisms, correcting categories, etc.).
 * So you could call Wikipedia conscious, if you want. You could also say that the United States is a conscious entity, and that your local City Hall is a conscious entity, and that in fact your local McDonald's is a conscious entity. Heck, your car becomes a conscious entity, when you're driving it. Your umbrella becomes a fairly conscious entity under this definition. But this is just a poor definition of consciousness: what you're saying, in the end, is that you're willing to abstract the fact that consciousness is coming from other definitely conscious beings. This is a very uninteresting definition of consciousness. Consciousness is interesting because it emerges out of unconsciousness. Put billions of essentially "dumb" neurons in the right configuration and you can have a sensible conversation with it. That's clever. Then having those neurons click buttons on a machine — not as clever. Not as impressive anyway.
 * In the interest of keeping consciousness interesting, I would say, no, Wikipedia is not conscious. It's users generally are (if anyone is), but Wikipedia is just a forum for conscious folks to interact, and not a conscious entity in and of itself. So I hold. --Mr.98 (talk) 03:03, 3 December 2011 (UTC)
 * Assumes facts not in evidence, namely that human consciousness (in the sense of subjective experience) is nothing more than the interaction of neurons. Precisely because consciousness is a subjective phenomenon, consciousness per se (as opposed to, say, the neurological correlates of consciousness) is not really amenable to study by physical science.
 * The other side of that coin is that we can really never know that someone else is conscious, nor that something else is not conscious. Could be that the keys on which I'm typing are crying out for vengeance, and I do not hear them. --Trovatore (talk) 03:17, 3 December 2011 (UTC)
 * I explicitly assume those facts, for the reasons stated. The only reason I could see to not assume such a thing is if you are trying to determine whether Wikipedia is more conscious than the individuals who contribute to it. Which I think is kind of a silly argument, but it's the only positive thing I could see getting out of questioning whether individual humans are conscious. I functionally define consciousness as whatever humans have, which I think works for the purpose of this discussion quite well, even if it is not hardly the last word on consciousness. --Mr.98 (talk) 14:41, 3 December 2011 (UTC)
 * Well, actually I define consciousness as whatever I have. All the rest of y'all could be p-zombies for all I really know.
 * But the assumption you're making that I'm challenging is materialism. In my view there is no satisfactory materialistic explanation of consciousness (by which, again, I mean subjective experience), and indeed cannot be, because the category of "subjective" does not exist in the materialist account.  People like Daniel Dennett affect to take the position that there is no such thing to be explained, or at least that's what their view appears to boil down to, to me.  But that simply cannot be taken seriously. --Trovatore (talk) 20:32, 3 December 2011 (UTC)
 * (EC) I don't think Wikipedia is even Turing complete, or at least, I'm not aware of any way that a normal Wikipedia user without any special privileges can use Wikipedia's servers as a Turing complete computational system. It's rather vague from a scientific perspective as to how exactly consciousness should be defined, but I think conscious entities at a minimum are Turing complete (except for memory limitations), and might possibly even be able to perform some processing that goes beyond Turing completeness (I personally doubt that, but it's a difficult question).  Wikipedia along with all of its users can certainly work as a Turing complete system, but Wikipedia's users all by themselves are conscious entities, so that's not saying much.  Red Act (talk) 03:22, 3 December 2011 (UTC)
 * What does consciousness have to do with what functions you can compute? My cat can't compute a lot of functions, but it is certainly my impression that he is conscious; that is, that he has subjective experience.  Of course I can't prove it, but then I can't prove it about you, either. --Trovatore (talk) 03:24, 3 December 2011 (UTC)
 * Your cat's brain performs some kind of information processing, without which your cat would be no more "conscious" than a pile of dirt. My presumption is that an adequately powerful Turing complete system would be able to simulate the information processing of your cat's brain closely enough that the result would be indistinguishable from consciousness.  In contrast, it would at least be extremely difficult to simulate your cat's brain with an information processing system that wasn't Turing complete (except for memory constraints), although I can't prove that it would be impossible.  My guess is that the information processing that your cat's brain is capable of, including the information processing involved in your cat's "consciousness", is equivalent in the sense of the Church–Turing thesis to that of a Turing machine.  Red Act (talk) 03:55, 3 December 2011 (UTC)
 * Well, I think you're completely wrong about that. I see now reason to think that a Turing machine is conscious, nor that a conscious entity needs to be able to emulate a Turing machine.  Heck, I can't emulate a Turing machine, in general, and yet I am definitely conscious, though of course I can't prove that to you. --Trovatore (talk) 04:00, 3 December 2011 (UTC)
 * I certainly wasn't claiming that all Turing machines exhibit consciousness. And you don't need to be consciously aware that you're performing information processing equivalent to that of a Turing machine, in order to be performing information processing equivalent to that of a Turing machine.  For example, arguably no software program written so far is consciously aware that it's performing information processing equivalent to that of a Turing machine, even though it certainly is doing so.


 * And unfortunately, without a rigorous definition of what exactly "consciousness" is, pretty much everything either you or I have said just consists of statements that are neither true nor false, and hence is of very limited usefulness. Red Act (talk) 05:36, 3 December 2011 (UTC)
 * A Turing machine is a mathematical abstract object, which can do things, such as count to a googol, that no human to my knowledge has ever done. You did qualify the claim by saying something like "except for memory constraints", but there is no such thing as a Turing machine with memory constraints.  If you add memory constraints it's no longer a Turing machine, but rather a finite deterministic automaton, and the Church–Turing thesis, at least as such, is out the window. --Trovatore (talk) 06:10, 3 December 2011 (UTC)


 * It can't think for itself. Its reaction to "stimuli" is because of human influence to it. We're the ones (humans, I mean) are the ones that make Wikipedia respond to vandals, etc. If it can't be conscious by itself it can't be conscious. 64.229.180.189 (talk) 06:08, 3 December 2011 (UTC)


 * Your programmable calculator is Turing-complete - computational complexity has no relevance to a discussion on consciousness In fact, while a general neural network is Turing-complete, the network in the brain may not be, and indeed has to reason to be, Turing-complete.


 * Whether or not an adaptive complex system like Wikipedia or a sort of superorganism (see also Gaia hypothesis) has a type of consciousness is an open matter worth philosophizing about. Scientific research into what a simple complex system (not an oxymoron, I swear) is actually or maximally capable of doing is ongoing. If you see what goes on inside a single cell every day, you'd swear it's an intelligent animal. My approach to research: "a cell is stupid - so what's the dumbest way to do X?" The better approach may be "at what point can X not be done in a stupid way?" SamuelRiv (talk) 06:19, 3 December 2011 (UTC)
 * Your programmable calculator is not in fact Turing-complete. Turing machines are mathematical objects; using the term to describe a physical machine is at best a metaphor. --Trovatore (talk) 06:35, 3 December 2011 (UTC)
 * I think this is beyond the point, but Wikipedia is as conscious as it is Turing complete, under the same argument I gave initially. You can post arbitrary code to Wikipedia pages and get the correct responses. How? Because there are users on the other end with Turing complete machines (or close enough to them) that can run the code and re-post it. But this is a poor definition of Turing completeness (e.g. a system that has access to other Turing complete systems), just as it is a poor definition of consciousness. --Mr.98 (talk) 14:44, 3 December 2011 (UTC)


 * To me it seems like asking if Wikipedia is conscious is one instance of asking whether demons/daimons (and perhaps angels, at least by some loose potential definition) are real. While they have been relegated to flashy, supernatural fiction, the premise doesn't seem as absurd as made out.  Our minds are, after all, often fairly loose confederations of more specialized processing, as exemplified in multiple personality disorder but nonetheless familiar to everyone who takes on a different persona behind the wheel or behind the keyboard, at work or at home.  Is it possible that some part of one person's mind can work with similar parts of other people's minds without that person being especially aware of it?  Is it possible for an "individual" to be defined as this association, as individuals are defined by the association of all the parts of a single brain?  Such an entity may be specious, but if so, perhaps the idea of the individual organism as the unit of consciousness is also.  Individuals might only be convenient units of inventory, like the "household" for the Census.  While all this seems pretty hypothetical, the sad truth is that today we see cruel and harmful ideas, more unspoken and unspeakable sentiments than actual beliefs on identifiable political issues, once again threatening to spread and infest the world.  With a reasoned but overly dogmatic religion of secular materialism we've abandoned such spiritual defenses as the ancients preferred, whether rites of exorcism or blowing the shofar or even banging on pots and setting off firecrackers, not due to any negative experimental result but simply by lacking any place in our philosophy to categorize such things.  Anyway, let's hope that Wikipedia is on the side of the angels. ;) Wnt (talk) 13:56, 3 December 2011 (UTC)

Quasar distance, time and the speed of light
I've just finished reading about quasars.

My question, regarding the below paragraph: If the speed of light is the ultimate speed at which anything can move and the universe is roughly 14 billion years old, how can a quaser be farther away then 14 billion light years?

"Properties: More than 200,000 quasars are known, most from the Sloan Digital Sky Survey. All observed quasar spectra have redshifts between 0.056 and 7.085. Applying Hubble's law to these redshifts, it can be shown that they are between 600 million[9] and 28 billion light-years away (in terms of proper distance)."

Mr. Hearrell redacted — Preceding unsigned comment added by 68.98.168.26 (talk) 02:52, 3 December 2011 (UTC)


 * When the light left the quasar it could be say 13 million light years away. However it is traveling at near the speed of light away from us.  So now it is 13+(a number close to 13) light years away.  You can also read Comoving distance and Metric expansion of space. Graeme Bartlett (talk) 03:10, 3 December 2011 (UTC)
 * Actually, it can be moving faster than the speed of light away from us. Metric expansion of space isn't motion in the regular sense, so the speed of light limit doesn't apply. --Tango (talk) 18:49, 3 December 2011 (UTC)

Keep in mind that because the universe is expanding, objects moving away from each other will move faster apart than if only one was moving. Heck froze over (talk) 22:56, 3 December 2011 (UTC)


 * In a expanding universe distant objects can move away from us faster than the speed of light without contradiction with relativity. That means we can currently see objects that are much further than the age of the universe. See Observable universe. That also mean that those objects will eventually disappear behind a horizon and their light won't be able to reach us anymore. Dauto (talk) 08:17, 4 December 2011 (UTC)

Yet another animal factoid for discussion - swans this time...
Heard on a late night radio phone-in the other day...

"Swans (Mute Swans this will be, considering my location) are unable to walk backwards - if you ever get attacked by one, let it bite down on your index finger, then place your thumb on the top of its beak. The swan is physically unable to move backwards, lacks the sense to move forwards and will be basically frozen on the spot for as long as you have hold of its beak - and you will be able to look it in the eye and say 'well, I bet you feel pretty stupid right about now'..."

May be paraphrasing slightly, but that was the gist of it. Strangely enough, that was not the first time that I'd heard someone say something vaguely along those lines, though I'll be damned if I can remember where I heard it before.

So, anyone able to confirm or debunk? I'm not a jackass, so it's not as if I'm ever actually going to find a swan and try this out. --Kurt Shaped Box (talk) 03:34, 3 December 2011 (UTC)


 * Not sure about swans, but other animals have difficulty backing up. Cats can't back down a tree, since it would involve them moving each foot up a bit first to unhook their claws.  They can't seem to figure this out. StuRat (talk) 05:26, 3 December 2011 (UTC)


 * I've watched lots of cats back down trees. It's a bit awkward, they turn around and jump nearer the ground, but they absolutely can do it. They'd rather find a head-first way, but they go backwards (bottom-first) where necessary. 86.164.60.202 (talk) 08:40, 3 December 2011 (UTC)


 * At least some of them can't figure it out, as I've seen (and owned) cats stuck up a tree that needed to be rescued. StuRat (talk) 17:32, 3 December 2011 (UTC)
 * They just love the attention! ;-) But seriously, if that were a frequent problem, evolution would get rid of it. --Stephan Schulz (talk) 22:38, 3 December 2011 (UTC)
 * Out of curiosity, once you have the swan in this position, what are you supposed to do? It sounds like you're as stuck as he is. --Trovatore (talk) 06:33, 3 December 2011 (UTC)


 * According to this source "the introduction of the two swan pedalos may have frightened [the wild swans] away for a time". So, I assume you need to wait for the converted all-terrain swan pedalo rescue vehicle to arrive.  Sean.hoyland  - talk 06:52, 3 December 2011 (UTC)


 * On the Swan's version of wikipedia there's an identical question. Turns out humans don't know how to back up, so if you grab them by the finger they're totally stuck. APL (talk) 07:06, 3 December 2011 (UTC)


 * Debunk. AFAIK, all birds that can walk can walk backwards, while they are digitigrade, there's no physiological reason why they can't. You don't see them do it for the same reason that you don't see humans walking backwards - it's awkward. It's also not exactly something biologists would study, and people (even birdwatchers) don't exactly spend all day watching domestic birds. I grew up in a farm, and while we didn't have swans, we had ducks, geese, chickens, and turkeys. All of whom I've seen move backwards at one time or another, usually when they are fighting for mating rights as it's necessary to keep the opponent in view. Even then they usually have to flap their wings to steady themselves in the same way that humans walking backwards have a tendency to reach their hands out to balance and to cushion a possible fall. I've seen this factoid applied to other animals - from ratites to kangaroos (all of those not true, though not exactly walking in the case of Kangaroos, but Kangaroos don't exactly walk anyway).


 * For visual proof: Swans walking backwards (leftmost swan).--  Obsidi ♠ n   Soul   12:29, 3 December 2011 (UTC)

Difference between ram pressure and friction?
According to Ram pressure, it is the ram pressure and not friction that causes a meteor to heat up when it enters an atmosphere. I'm a bit confused as to what the difference is. It seems like they are basically the same thing. ScienceApe (talk) 04:24, 3 December 2011 (UTC)
 * My guess is that what it's saying is that the air being compressed heats up due to adiabatic compression, and that heat is then conducted to the rock, rather than the rock heating up by direct friction with the air. In some sense, sure, it's still friction, but a different sort.  I'm kind of guessing though. --Trovatore (talk) 04:27, 3 December 2011 (UTC)
 * Your explanation is mostly correct -- see Stagnation point and Atmospheric reentry for more details. 67.169.177.176 (talk) 04:48, 3 December 2011 (UTC)
 * I thought we had an article on aerothermal heating. There are a variety of components that produce heat: gas dynamics, skin friction, and even chemical reactions between gas and surface molecules.  Like all real-world physics, the full analysis reveals all sorts of contributing factors.  Nimur (talk) 15:08, 3 December 2011 (UTC)

Incorporating sounds in dreams
Is there a name for the phenomenon (if that's the right word) of having a sleeping person listen to certain external sounds (alarms, horns if the sleeper is in a car, voices, etc.) and then having the brain incorporate these sounds into one's dream, that didn't necessarily deal with the dream in the first place? 64.229.180.189 (talk) 06:12, 3 December 2011 (UTC)


 * You already mentioned it. :) Instances where external stimuli are incorporated into dreams are known as "dream incorporation".--  Obsidi ♠ n   Soul   12:53, 3 December 2011 (UTC)

Sound Frequency and Hearing Damage
I know that when a person is exposed to loud noise for an extended period of time they begin to suffer from hearing loss. My question is however, can especially high frequency and low frequency noise (that is beyond a person's awareness) also damage hearing? For example, a given person's hearing range is from 80Hz-15kHz. Could their hearing be damaged if they were exposed to loud noise in ranges such as 1-20Hz, or 18-30kHz? Any good information on this is appreciated. Lord Arador (talk) 06:14, 3 December 2011 (UTC)


 * I don't have any proof to back up this claim, but I talked to a record producer (independent) many years ago who explained to me that audiophiles shouldn't drive with their windows rolled down for several reasons: one, the fluctuating, strongly pulsating air (especially noticeable with one window down while driving at a good rate) can agitate and/or increase risk of damage to one's hearing, as well as an extremely low frequency that cannot be heard being created by the airflow passing over a window like air being blown over an opened bottle, and that the frequency was low enough that though it couldn't be heard, it could still increase risk of damage to one's hearing. In other words, he drove to and from work with closed windows (and apparently without listening to the radio or other music either, though simply to rest his ears after a day's work). Is all this true? He's the one with the audio magazines laying around the studio, so I'm sure it's been discussed. I'm curious about any responses to this question as well. – Kerαu noςco pia ◁ gala xies 06:53, 3 December 2011 (UTC)


 * According to Ultrasound and Sonic weapon, it looks like the answer in both cases is yes. The Ultrasound page has some links with more info on the topic. Pfly (talk) 07:26, 3 December 2011 (UTC)


 * Despite the above, if it isn't causing you any discomfort at the time it is unlikely that ultra low or ultra high frequencies will damage your hearing in the long term. Very very loud low frequency can blow your eardrums, which may result in some long term hearing damage. The example given of the noise in the car is frankly pseudoscience. FWIW I worked in NVH for 15 years or so. I would say that 'normal' levels of noise in the industrial era are probably enough to cause long term damage. Greglocock (talk) 06:03, 5 December 2011 (UTC)
 * I think the low-frequency noise from car windows can be very real - it is physically painful to my ears to leave a single rear window open in a car for any length of time, as the air sort of "gurgles" in and out - though it doesn't bother me to leave the front windows open, or a front and a rear at the same time. Wnt (talk) 21:00, 7 December 2011 (UTC)


 * See Sonic weapon and http://www.lowertheboom.org/trice/infrasound.htm.
 * —Wavelength (talk) 23:22, 6 December 2011 (UTC)

Einstein's thought experiment about simultaneity & detection of absolute motion
In Einstein's thought experiment about the observer dependent nature of simultaneity (depicted in an accompanying diagram in the referenced article), if the observer on the train knows a priori that the lightning bolts are going to hit the two ends of the train car simultaneously, wouldn't he be able to detect the train's state of motion by comparing the apparent timing of the two lightning events as they are observed? This seems to contradict the assertion that an observer in a box in uniform linear motion cannot ascertain its velocity.

About the part of the observer knowing the simultaneous lightning hits a priori, we can achieve that by modifying Einstein's thought experiment like this: there are two small robotic vehicles initially at the center of the train car with synchronized clocks; the two robotic vehicles slowly move to opposite end of the train car; at the same pre-determined time, both robotic vehicles give off a flash. This is similar to Einstein's thought experiment, except that the observer in the train car knows when the two flashes are supposed to happen, without having to rely on the apparent timing of the observed flashes.

Which part did I have it wrong? --98.114.146.169 (talk) 09:50, 3 December 2011 (UTC)


 * If the observer in the train sends the identical robots off at the same speed relative to him in opposite directions then they will emite their flashes at the same time in his frame of reference and these flashes will reach him simultaneously. However, from the point of view of the observer standing by the tracks, the robots are not travelling at the same speed relative to the observer in the train because of the relativistic velocity-addition formula. Also, the robot's clocks are going at different rates - time is travelling more slowly for the robot travelling towards the far end of the train than for the robot travelling towards the near end. Therefore the nearer robot will emit its flash before the further one in the frame of reference of the observer standing by the tracks . But the light flash emitted by the nearer robot has a greater distance to travel in the frame of reference of the observer standing by the tracks to catch up with the observer in the train. So both observers agree that the two light signals reach the observer in the train simultaneously. Note that simultaneity is only relative for events that are separated in space ; events that occur simultaneously and at the same point in space will be simultaneous for all observers. Gandalf61 (talk) 11:41, 3 December 2011 (UTC)


 * About the robots' clocks going at different rates, I actually had considered that, that's the reason I made the robots move slowly to the ends of the train car. I did a rather simple (simplistic?) calculation to find out the relativistic slowdown of the robots' clock during the movement. It seems that the accumulated slowdown is dependent on the robots' speed. If that is a correct observation, the time difference between the two robots' clocks can be made arbitrarily small by making them move slowly. And if it makes a difference, we can assume that the robots synchronize and move to their respective position when the train is stationary, and the whole train accelerate to some high final velocity. In any case that the small time difference in the robots' clocks don't seem to be critical to the "paradox".


 * The important part that I'm not sure is, whether the light flashes from the robots will reach the observer at different times due to the train's motion, as in the case of Einstein's thought experiment. If they do, and that assumes the flashes from the robots are like the lightning bolts in Einsteins thought experiment, the timing difference perceived by the observer can be made much greater than the clock difference between the robots. If the flashes from the robots are not like Einstein's lightning bolts, what makes them different (light doesn't need a medium for propagation and can travel through free space)?


 * I think I'm missing something but I don't know exactly what. --98.114.146.169 (talk) 15:42, 3 December 2011 (UTC)


 * If the observer in the train sends his robots off in opposite directions at the same time and at the same speed and with instructions to emit a flash of light after the same interval then in his frame of reference the flashes will be emitted simultaneously, but in the frame of reference of the observer standing by the tracks the flashes will not be emitted simultaneously. This is different from Einstein's lightning thought experiment where the lighting strikes at each end of the train are simultaneous in the frame of reference of the observer by the tracks, but not in the frame of reference of the observer in the train. In your robot scenario both observers agree that the flashes of light from the robots reach the observer in the train at the same instant. In Einstein's lightning scenario, both observers agree that the flashes of light from the lightning reach the observer in the train at different times, but they disagree on why this is; the observer by the tracks says it is because they travel different distances, whereas the observer in the centre of the train says they travelled the same distance but they were not emitted simultaneously. Gandalf61 (talk) 10:29, 4 December 2011 (UTC)

Gauss 651
Now that Ray Bradbury has agreed to allow his novel Fahrenheit 451 (so named, because this is the ignition temperature of paper) to be re-releases as an e-book, should he consider retitling it to Gauss 651 to indicate the this is the magnetic flux density required to wipe a complete library off a hard disk drive. This would help bring his novel up-to-date for the current generation. Together with a few minor other changes,  like Montag stealing a pen-drive with an e-book copy of How To Program In Unix and unmanned drones to  replace the mechanical hounds etc.,  it would still preserve the underling message  that Ray was trying to convey -which is every bit a poignant to-day as it was then. --Aspro (talk) 18:10, 3 December 2011 (UTC)
 * An interesting idea, but do you have an actual question that you would like us to find references for? --Tango (talk) 19:00, 3 December 2011 (UTC)
 * Wouldn't work. F451 is very much a product of its own time. Updating it to superficially look like it was a modern work would produce bizarre results. APL (talk) 20:17, 3 December 2011 (UTC)
 * Fire is pretty effective at wiping digital media, too&mdash;whereas even fairly intense magnetic fields won't wipe a thumb drive, compact disc, or DVD. (This becomes even more important as solid-state hard drives become more common.)  Still, as Tango notes, there doesn't seem to be any question there for which we can offer you references.  Perhaps you should contact Ray Bradbury?
 * A more philosophical question for you&mdash;is it always a good idea to 'update' novels so that they happen in a modern environment? Is there irony in a move to rewrite and supersede 'old' versions of novels (particularly this novel) because they contain historical or archaic references and concepts that might confuse or distract the modern reader?  Should important books be replaced and 'reinterpreted' every few decades to be sure that they still convey the 'correct message' as bluntly and unsubtly as possible, and to discourage their readers from needing to do any independent research to contextualize material that falls outside their own experience?  TenOfAllTrades(talk) 20:25, 3 December 2011 (UTC)


 * What makes you think that everyone has enough free time to do in-depth research. A book springs to mind (that  you may know of and have read), has been constantly up dated into the popular vernacular. This web site gives just some of the available versions. . Can you read and understand the original? Where is the discouragement? If the new version is interesting, don't you think that it would spur people on to read the original text?--Aspro (talk) 21:42, 3 December 2011 (UTC)


 * So, are you claiming that Fahrenheit 451 equates to the Bible or are you going further to claim that Bradbury equates to the Apostles? Or, more precisely, are you trying to keep a joke that nobody found to be even slightly humorous going on and on in an absolutely trollish manner? -- k a i n a w &trade; 21:48, 3 December 2011 (UTC)
 * Doesn't make sense. There are plenty of new books out there. If you want a modern novel why not read one of them? Books and movies are not intended to be evergreen like an oral tradition (Then end of F451 not withstanding). They're supposed to be stories and ideas frozen in time. Sometimes the age and obscurity ruins them, but sometimes it makes them better, oddly enough. For example, Alice's Adventures in Wonderland is full of pop culture references that a child from that era would catch. The book would be more or less ruined if you updated it to use modern references.    Same with the Sherlock Holmes stories, modern readers enjoy those books as much for the taste of victorian england as for the adventures.
 * This applies to science fiction too. Just because the stories take place in "the future" they're not immune from being artifacts of their own time.  They reflect the hopes and fears of the public of when they were written.  If you updated "The Time Machine" so that instead of the Morlocks you got zombies caused by nano-technology and cel phones, you'd totally ruin the book. Not only that, you'd totally break any links it has to the history of Science fiction.
 * Nah, Good modern science fiction is being written every day. There's no reason to try to transmogrify old science fiction. APL (talk) 22:29, 3 December 2011 (UTC)
 * I found an ad for a super duper spook degausser that uses 40,000 gauss ( http://www.datadev.com/degausser-t4.html ) and discussions which give figures in the thousands or more ( http://forums.anandtech.com/archive/index.php/t-1092408.html ). I don't think 651 is a likely figure, and due to the nature of degaussing (which apparently depends on the coercivity in oerstads but also the cycling of the magnetic field) it's a more variable process than simply heating paper to a flash point.  So I'm not sure if any direct equivalent exists.
 * I think that it is very common to update and rework old stories in sci-fi (Beowulf is a favorite); unfortunately due to glorious capitalist system most efficient of all possible universes this is virtually illegal for anything written in the 20th century. Wnt (talk) 00:50, 4 December 2011 (UTC)
 * That's why you gotta write your own stories, as I do. Or use an older source, like the Volsungs Saga, and move the story to the present day.  (Would you believe I actually got a plot outline for a sci-fi detective thriller based on that source?) 67.169.177.176 (talk) 07:15, 4 December 2011 (UTC)


 * Yes, I can believe that. As there are only 7 basic plots, . So it only require a rich imagination to re-cloth it in futuristic back-drop. It goes in the other time direction as well. George Lucas's Star Wars always opens with ''A long time ago in a galaxy far, far away....". It is nice to see your re- working on something that is well out of copyright – and as Ray's work is still in copyright, I'm just suggesting he likewise, re-works his back catalog himself. It geriatric rock-stars can do it, why shouldn't  he. There isn't a difference in opportunities and reason between all three of you when you look at  it logically.--Aspro (talk) 18:13, 4 December 2011 (UTC)
 * I'm reluctant to read a book which advocates what seems like a basically absurd premise, but Olly Buxton's review at that link seems persuasive. Besides, if you boil down a plot so far as to say "it's a voyage and return", that doesn't sound like enough of a plot to copy.  Also, there's a difference between adapting the work and copying the plot - for example, the movie Outlander (which seemed far better than its cousins no matter what the critics say) manages to incorporate something of the situation of the original story and many recognizable individual elements, while being so innovative that it seemed like it took a third of the movie before I even realized it was based on that. Wnt (talk) 19:12, 4 December 2011 (UTC)
 * "Should important books be replaced and 'reinterpreted' every few decades to be sure that they still convey the correct message.'" That's a very "1984" idea.. ;) Vespine (talk) 00:34, 5 December 2011 (UTC)


 * I should also point out that in some cases, an author's contract with his/her publisher may not grant him/her the right to create derivative works from the original publication, depending mainly on who owns the rights to the publication. This used to be very common in the past, and is still often seen in the traditional publishing market; for self-published books, however, the author generally retains all rights and is therefore free to rework the publication any way he/she wants.  In the case of Bradbury, in particular, I think it very likely that reworking Fahrenheit would cause him to commit copyright infringement against "himself" (actually the publisher who signed the contract with him).  This is VERY counterintuitive, but that's the way it works in the literary business. 67.169.177.176 (talk) 02:12, 5 December 2011 (UTC)
 * It's not counterintuitive at all - provided one understands that the point of copyright is not to reward authors, who like all laborers are merely beggars looking for scraps where they're tossed, but to maintain the supremacy of Capital over all things. Wnt (talk) 06:24, 5 December 2011 (UTC)
 * Is J. K. Rowling (the first person ever to make $1 billion from fiction writing) a "beggar looking for scraps to be tossed"?! Is Tom Clancy (another successful author) one?!  What you just said is COMPLETE NONSENSE -- authors who are successful, like Clancy or Rowling, in fact get richly rewarded in the monetary sense under the capitalist system, even if they don't get to keep their copyright under their contract with the publisher!  And if you don't like the idea of having to sell your copyright to the publisher, you can try to have your agent look for one that lets you retain full rights, or, as I said before, you could try to have your book self-published by one of these places (but then the downside is, you have to pay the up-front expenses, and also do your own promo stuff -- which can be a big hassle).  Why are there so many commies here on Wikipedia? 67.169.177.176 (talk) 00:12, 6 December 2011 (UTC)

Using cellphone in Atlantic
I'm writing a novel, and this answer could help me with the development of it. Now, I have these modern teenagers being left stranded with several adults, and many of them try to use their cellphones for help. Now, they would be stranded on an uninhabited island near the middle of the Atlantic Ocean (and the island would not have any cellular radio towers). Would applications such as BlackBerry Messenger especially, regular cellphone calls, texting perhaps, etc., work out there? 64.229.180.189 (talk) 21:53, 3 December 2011 (UTC)
 * Presuming you mean Atlantic Ocean rather than Atlantic Island, the answer is no, cell phones would not work. A satellite phone would work, but not a cell phone. Looie496 (talk) 22:04, 3 December 2011 (UTC)
 * Yes, sorry, I'll fix that. 64.229.180.189 (talk) 22:09, 3 December 2011 (UTC)


 * To be a bit more precise... You asked if they would work. They would keep functioning until the battery died (assuming they didn't have electricity to recharge them). While functioning, they would be limited to local use only. They couldn't make a call, send a text, or receiving calls or texts. They could play Angry Birds. -- k a i n a w &trade; 22:35, 3 December 2011 (UTC)

That's why you need to buy one of these. Count Iblis (talk) 22:58, 3 December 2011 (UTC)


 * The max range of a standard cell site is only 50 miles or so under ideal conditions. The Atlantic Ocean is thousands and thousands of miles wide. If you are more than 50 miles from the coast (which is not very far in terms of geographic space — Cuba is about twice that from Florida), then a standard cell phone is out of luck, no signal at all. And that presumes really quite ideal conditions. --Mr.98 (talk) 17:39, 4 December 2011 (UTC)


 * Maybe HAM radio could work for transatlantic communications. ~ AH1 (discuss!) 21:37, 4 December 2011 (UTC)


 * I think that some variant of walkie-talkie (900MHz) might serve this role. According to the article some small boats use them.  Or a child on a plane might have one as a toy and have it on in defiance of regulations.  I don't  know if it's actually feasible for one of the teenagers to make contact with such using one, but it's certainly plausible for one of them to have a walkie-talkie...  of course, the person they talk to needs to be within a fairly short range! Wnt (talk) 21:21, 7 December 2011 (UTC)