rob@hhb.UUCP (Robert R Stegmann) (05/24/84)
The Earth is flat!
The Earth is fixed at the center of the Universe!
If God had meant man to fly, He would have given him wings!
The first man to walk on the moon will be engulfed by dust!
Perpetual motion is unattainable!
The speed of light can never be exceeded!
A use of 'negative data', often expressed as a general
proscription, is to save people the trouble of seriously
pursuing paths of investigation which others have shown to be
fruitless. The weight of such a proscription is based upon the
credibility of the issuer, as well as the strength of the logical
argument supporting his position.
Historically, many such injunctions were based upon 'gut
feelings' and 'common knowledge' rather than experiment and reason.
They were held either by people with vested interests in preserving
the extant status quo, or people unwilling or unable to do more than
parrot the views of others. Those brave souls who dared to challenge
public opinion did so at their own expense and risk, and were rarely
rewarded for their efforts, or vindicated within their lifetimes.
Regardless of how many blanket proscriptions have been shown
to be groundless in the past, and regardless of how satisfying the
tales of an underdog's vindication might be, however, modern man
must fight public ignorance in a different theatre, where the villains
are not so villainous and the public not so ignorant.
First, Einstein was certainly neither uninformed nor did he
have a vested interest in a universal speed limit. Second, his
argument is based upon solid logic, supported by experimental
evidence. Third, his 'followers' are not merely evangelists seeking
to spread his gospel and silence blasphemers.
Possibly the most serious effect of adherance to Einstein's
ideas by the modern scientific community, is NOT that it will cause
them to view with skepticism ideas about FTL travel, but that it might
cause them to actively shun all such ideas, and possibly overlook a
valid one! Modern research requires huge sums of money, and the
people who allocate funds are influenced primarily by the majority
views of the scientific community. Society simply cannot afford to
pursue what experts hold to be blind alleys in research.
But it is as important today as in the past, nay, more so, that
'heretical' views not be totally ignored by the community! So while
it is unfair and even naive to analogise 'FTL travel is impossible'
with 'The Earth is flat', it remains as unwise as ever to accept any
doctrine to the point where all nonconforming thought is extinguished.
rob
{decvax,ihnp4,allegra}!philabs!hhb!robnessus@mit-eddie.UUCP (Doug Alan) (07/13/85)
> From: franka@mmintl.UUCP (Frank Adams) > In article <4577@mit-eddie.UUCP> nessus@mit-eddie.UUCP (Doug Alan) writes: >> According to Special Relativity, faster-than-light travel is >> exactly equivalent to traveling backwards in time: there is no >> difference. > Stories assuming ftl travel generally (implicitly) assume that special > relativity is wrong, that there is a preferred frame of reference, which > approximates our own here on Earth. Admittedly, most do this because the > author does not understand special relativity, BUT it is a consistent > assumption -- just not very likely. One would think that the Michelson-Morley experiment fairly well ruled out this unlikely possibility nearly a hundred years ago! > From: Peter Alfke <Alfke.pasa@Xerox.ARPA> > Actually, according to Special Relativity, faster-than-light travel is > just plain impossible. All the sqrt(v^2 / c^2) terms turn imaginary . No. Special Relativity just says that you can't accelerate through the speed of light. It doesn't say you can't travel faster than the speed of light. Haven't you ever read any of the stuff on tachyons? The tachyon theory is completely consistent with Special Relativity. They always travel faster than light, and they travel backwards through time. > Any story in which ftl works is tacitly assuming that something new > has superceded Relativity in the same manner as Relativity superceded > Newtonian mechanics. That, or the author just doesn't care about all > the physical ramifications; he/she just needs ftl to tell the story. > (Either approach is equally valid in my book.) Something might come along that might be more general than Special Relativity (gee like General Relativity), but it's incredibly unlikely that anything will ever contradict Special Relativity. Special Relativity is mathematically derived from some very simple assumptions.. If Special Relatvity were found to be incorrect, it would mean that at least one of those simple assumptions is incorrect. It is EXTREMELY unlikely that any of these simple assumptions is incorect, and if one of them were to be found to be incorrect, it would have far more ramifications than merely FTL travel, which then should be dealt with in the SF story. "This is the time And this is the record of the time" Doug Alan nessus@mit-eddie.UUCP (or ARPA)
EVAN@SU-CSLI.ARPA (07/13/85)
From: Evan Kirshenbaum <evan@SU-CSLI.ARPA> >Actually, according to Special Relativity, faster-than-light travel >is just plain impossible. All the sqrt(v^2 / c^2) terms turn >imaginary... I'm sure this shows a shocking naivitee on the subject of relativistic physics, but this argument never made much sense to me. So what if the multiplier turns imaginary. Imaginary numbers have rights too. Besides, since everything on the ship would have an imaginary mass, their ratios would still be real. I've always been surprised that physicists would throw up their hands at this and say "it's impossible" rather than finding out just what the consequences of having imaginary mass, velocity and time would be Evan Kirshenbaum -------
jagardner@watmath.UUCP (Jim Gardner) (07/15/85)
[...] A little relativity theory: we begin with the basic law of physics F=ma. What this says is that Force is proportional to acceleration (provided the mass of the accelerating body remains constant). Now one way of interpreting special relativity says that F=ma is ONLY true for velocities that are small in comparison to the speed of light. When you get really fast, the law breaks down. You need a lot more force to get the same amount of acceleration once you get going fast enough. The faster you're going, the more force you need to get even a little increase in speed. Finally, it takes an infinite amount of force to push something past the speed of light. All this means is that you can't just put a big rocket engine on your space-ship and propel it to faster-than-light speeds. Somehow or other, you have to "get out of the game"; warp drives, for example, bop out of normal space into a different sort of environment and bop back into normal space somewhere else, by-passing the normal space in between. Another approach is to diminish the mass of your ship in some currently unknown way, to compensate for the diminishing return you're getting from the force you apply. Tachyons get around the problem by _starting_out_ going faster than the speed of light. Since they're already past the boundary, you don't run into the infinite force problem, so they can happily do whatever they want. Jim Gardner University of Waterloo P.S. Physicists are greatly disquieted by the suggestion that F=ma could ever be untrue. Therefore they usually keep the equation and redefine the "m" (mass) so that the equation still works at high speeds. They say that a moving particle has a higher mass than a particle at rest; as a particle moves faster and faster, its mass increases, until at the speed of light, its mass is infinite, which is it would take infinite force to increase the particle's speed. Of course, then the physicists have to explain why motion adds to a particle's mass. Their explanation is that the kinetic energy of the particle is as good as mass, and indeed, energy is the same as mass for the purposes of relativity. Put in equation form, this is E=m. And if you use archaic units of measurement, it turns out that you need a conversion factor in this equation, so you get E=mc**2.
wombat@ccvaxa.UUCP (07/18/85)
/* Written 2:26 pm Jul 13, 1985 by EVAN@SU-CSLI.ARPA in ccvaxa:net.sf-lovers */ I'm sure this shows a shocking naivitee on the subject of relativistic physics, but this argument never made much sense to me. So what if the multiplier turns imaginary. Imaginary numbers have rights too. Evan Kirshenbaum /* End of text from ccvaxa:net.sf-lovers */ Really! The subsonic aerodynamics equations will produce complex results if you try to put supersonic speeds in them. So of course everyone used to say that it was impossible to fly at supersonic speeds. The problem is that the subsonic equations include implicit assumptions about such things as how incompressible air is, and those assumptions do not hold for supersonic speeds. If you use the correct equations, transonic and supersonic flight are just dandy. It seems reasonable to me that the same sort of thing could be true of faster-than-light speeds, i.e., we are making assumptions on this side of the barrier about physical conditions on the other side that could be quite wrong, but then I want to believe we can break the light barrier. "When you are about to die, a wombat is better than no company at all." Roger Zelazny, *Doorways in the Sand* Wombat ihnp4!uiucdcs!ccvaxa!wombat
andrew@orca.UUCP (Andrew Klossner) (07/19/85)
>> Actually, according to Special Relativity, faster-than-light travel >> is just plain impossible. All the sqrt(v^2 / c^2) terms turn >> imaginary... > > I'm sure this shows a shocking naivitee on the subject of relativistic > physics, but this argument never made much sense to me. So what if > the multiplier turns imaginary. Imaginary numbers have rights too. > Besides, since everything on the ship would have an imaginary mass, > their ratios would still be real. I've always been surprised that > physicists would throw up their hands at this and say "it's > impossible" rather than finding out just what the consequences of > having imaginary mass, velocity and time would be First, let me state my bias. There are two camps: those that believe that FTL can never be achieved, period, there's no point talking about it; and the rest of us. I'm one of the rest of us. Mankind has been overcoming "insuperable" limits throughout history. It wasn't so long ago that many of the best brains in aerodynamics were convinced that no aircraft would ever reach the speed of sound. Now to the math ... FTL problems predicted by special relativity don't center on objects going faster than light, but rather are concerned with objects accelerating up to and through the speed of light. The mass equation, for example, is m = m0 / sqrt(1 - (v^2)/(c^2)) where m is mass, m0 is rest mass, v is your velocity as perceived by some observer, and c is the speed of light. If an observer sees you achieve the speed of light, that observer would also see your mass become infinite (m0 / 0). I think it's legitimate to throw up my hands and say that infinite mass is impossible. When I contemplate achievement of FTL, I imagine a mechanism that involves changing your velocity from sub-light to super-light without going through light. This would be a discontinuous, "catastrophic" change. You would then avoid the infinite mass and go directly to imaginary mass. Of course, we still have the problems of violation of causality. Tachyon theory avoids this by stating that there can be no interaction at all between a sub-light and a super-light object, so the tachyon cannot communicate information to the sub-light observer. -=- Andrew Klossner (decvax!tektronix!orca!andrew) [UUCP] (orca!andrew.tektronix@csnet-relay) [ARPA]
royt@gitpyr.UUCP (Roy M. Turner) (07/19/85)
In article <15754@watmath.UUCP> jagardner@watmath.UUCP (Jim Gardner) writes: > >P.S. Physicists are greatly disquieted by the suggestion that F=ma >could ever be untrue. Therefore they usually keep the equation and >redefine the "m" (mass) so that the equation still works at high >speeds. They say that a moving particle has a higher mass than a >particle at rest; as a particle moves faster and faster, its mass >increases, until at the speed of light, its mass is infinite, which >is it would take infinite force to increase the particle's speed. >Of course, then the physicists have to explain why motion adds to >a particle's mass. Their explanation is that the kinetic energy >of the particle is as good as mass, and indeed, energy is the same >as mass for the purposes of relativity. Put in equation form, >this is E=m. And if you use archaic units of measurement, it turns >out that you need a conversion factor in this equation, so you get >E=mc**2. So mass increases...why not? It makes as much sense for a physical "constant" of a body not to be constant as it does for an invariant law to be changeable, no? After all, as a body approaches the speed of light, its length decreases and time slows...why not funny stuff with mass, too? Roy -- The above opinions aren't necessarily those of etc, etc...but they should be!! Roy Turner (a transplanted Kentucky hillbilly) School of Information and Computer Science Georgia Insitute of Technology, Atlanta Georgia, 30332 ...!{akgua,allegra,amd,hplabs,ihnp4,seismo,ut-ngp}!gatech!gitpyr!royt
rubin@mtuxn.UUCP (M.RUBIN) (07/20/85)
Warp drive as found in ST doesn't seem to bounce you out of one part of space and suddenly into another; instead you cruise steadily, at (warpfactor^3)*c. Even stranger, stars keep their normal colors; no blue shift ahead nor red shift astern. Therefore I suggest: the Enterprise's warp drive creates a zone of Newtonian physics around the ship. F=ma with constant mass regardless of velocity, and those big antimatter engines just accelerate the ship right past c. But, hmm, why do they always have problems with decaying orbits when their power runs down? Aha -- it's not Newtonian, it's ARCHIMEDEAN physics; all objects tend to remain at rest unless propelled by an impulse! (cf. Scientific American, "Naive Physics", I don't have the issue in front of me but it was sometime in '83-'84.)
throopw@rtp47.UUCP (Wayne Throop) (07/22/85)
> [...] The subsonic aerodynamics equations will produce complex results > if you try to put supersonic speeds in them. [...] It seems reasonable > to me that the same sort of thing could be true of faster-than-light > speeds, i.e., we are making assumptions on this side of the barrier > about physical conditions on the other side that could be quite wrong, > but then I want to believe we can break the light barrier. > Wombat > ihnp4!uiucdcs!ccvaxa!wombat I agree with this posting to a large degree, but I'd like to add a point or three. First, most people don't see the problem at all, saying in effect "well, the light-speed problem is just another limit, and we'll get around to solving that one one of these days". The problem isn't that we don't have equations that model what would happen in FTL, (supersonic flight) or that we think that the barrier is beyond our current technology (heavier than air flight). One problem is that we don't know of any phenomna at all that exhibit FTL travel. Heavier than air flight was obviously possible (birds do it), and supersonic speeds in air were obviously possible also (metiorites do it). Another problem is that we *do* have equations that model what should happen at FTL speeds, and they all involve causality violation, or imply time travel in one form or another. I for one find this discouraging, but am unwilling to "give up hope", so to speak. Nevertheless, FTL *is* fundamentally more difficult than any of the other "limits" that folks have surmounted in the past. Second, I find some SF treatments of FTL very implausible. Some simply reject the notion that a fundamental breakthrough is needed to make FTL possible, and have FTL occuring without the slightest justification. Even Star Wars did better than that, and SW isn't noted for scientific plausibility. This (to me) is somewhat more jolting to the suspension of disbeleif than having a character in a story decide that all that is needed to acheive heavier than air flight is to flap the arms fast enough... and succeed at it! And thirdly, most SF ignores the problem that FTL implies time-travel. However, this doesn't jar my enjoyment of the story, since I just assume that this little problem has been handled as part of the theoretical breakthrough (warp drive, tachyon converter, doubletalk generator, or whatever), that solved the FTL problem in the first place. -- Wayne Throop at Data General, RTP, NC <the-known-world>!mcnc!rti-sel!rtp47!throopw
bsa@ncoast.UUCP (Brandon Allbery) (07/26/85)
Expires: Quoted from <1622@orca.UUCP> ["Re: FTL Travel"], by andrew@orca.UUCP (Andrew Klossner)... +--------------- | >> Actually, according to Special Relativity, faster-than-light travel | >> is just plain impossible. All the sqrt(v^2 / c^2) terms turn | >> imaginary... | > | > I'm sure this shows a shocking naivitee on the subject of relativistic | > physics, but this argument never made much sense to me. So what if | > the multiplier turns imaginary. Imaginary numbers have rights too. | | .....................................................It wasn't so long | ago that many of the best brains in aerodynamics were convinced that | no aircraft would ever reach the speed of sound. Now to the math ... | | FTL problems predicted by special relativity don't center on objects | going faster than light, but rather are concerned with objects | accelerating up to and through the speed of light. The mass equation, | for example, is | | m = m0 / sqrt(1 - (v^2)/(c^2)) | | where m is mass, m0 is rest mass, v is your velocity as perceived by | some observer, and c is the speed of light. If an observer sees you | achieve the speed of light, that observer would also see your mass | become infinite (m0 / 0). I think it's legitimate to throw up my hands | and say that infinite mass is impossible. +--------------- But one message on here said that the mass equation was just a way of keeping F=ma legit at high speeds. So? What if it isn't so? What if the physicists did it to themselves again -- preserved their prejudices and thereby got the wrong result? (The alternate ways to balance the equation are to have the acceleration increase, or thr force to decrease.) But who said that either had to happen? Maybe F=ma is just plain FALSE at high speeds, and the work- around is only approximately true, like approximations to functions which disappear at some points when the real function doesn't; I remember seeing some in my calculus courses, but I don't remember what they were any more. Question on a similar subject: What is ``seen'' by sonar when a supersonic plane goes trans-sonic? There are two possibilitis; one, which appears to match the facts we see, sounds suspiciously like what the Special Relativity guys say happens at lightspeed... One possibility is that the sonic record just fades out as the plane crosses the sound barrier. The other is that the record has less and less gain as the plane increases, then suddenly jumps to a maximum, then disappears. The maximum is the ``sonic boom''. I suspect this is similar to the idea that lightspeed particles (i.e. photons) are ``primarily'' energy (i.e. can't hit like a bullet, but CAN refract), and, if so, may say that S.R. is wrong from the start. (And ships going trans-light would cause a ``light boom''; shades of ST:TMP! :-) Any comments? --bsa -- Brandon Allbery, Unix Consultant -- 6504 Chestnut Road, Independence, OH 44131 decvax!cwruecmp!ncoast!bsa; ncoast!bsa@case.csnet; +1 216 524 1416; 74106,1032 ========================> Trekkies have Warped minds. <=======================
ethan@utastro.UUCP (Ethan Vishniac) (07/29/85)
> I think it's legitimate to throw up my hands > | and say that infinite mass is impossible. > +--------------- > > But one message on here said that the mass equation was just a way of keeping > F=ma legit at high speeds. So? What if it isn't so? What if the physicists > did it to themselves again -- preserved their prejudices and thereby got the > wrong result? > > Any comments? > -- > Brandon Allbery, Unix Consultant -- 6504 Chestnut Road, Independence, OH 44131 Sure. The theory of relativity says that it takes infinite energy to accelerate a particle up to the speed of light. Whether one chooses to regard this as infinite mass as well is a matter of formalism. In many ways it is convenient to restrict one's definition of mass to "rest mass", but this is a trivial point. The important point is that the effects of SR can be seen, and are seen, in particle accelerators whenever the particle energy becomes comparable to the particle rest mass. This shows up both in time dilation (the apparent half-life of particles increases) and in the increasing amount of energy necessary to add to a particle's velocity. SR is certainly correct in the sense that Newtonian dynamics is correct, ie. correct in the regime in which it is normally applied. FTL enthusiasts had better hope for an extension of physics that allows FTL, not a revocation of SR. -- "Don't argue with a fool. Ethan Vishniac Borrow his money." {charm,ut-sally,ut-ngp,noao}!utastro!ethan Department of Astronomy University of Texas
draughn@iitcs.UUCP (Mark Draughn) (08/08/85)
The annoying thing about the idea of FTL travel is what happens when an object
travels faster than the speed of light. It's relativistic mass drops to zero.
At least the real part does. The imaginary part shows up, and then dwindles
away toward zero as velocity increases without bound. The problem with FTL
travel then depends on what "imaginary" means in the real world. (It's easy
to forget that "imaginary" is just a word and assume that all this means that
objects traveling above the speed of light have no mass. Depending on one's
school of thought, this may or may not make FTL travel impossible.) I don't
know what "imaginary mass" means in the real world, and I don't think anyone
else knows either.
Mark Draughn
ihnp4!iitcs!draughn
P.S. Of course you can't just accellerate up through the speed of light.
Coming from the lower side of c, mass increases toward infinity.