wolit@rabbit.UUCP (10/06/83)
A racing car driver, MacLean, Had the fastest machine on the scene. Driving faster than light, With no cops in sight, He'd blue-shift the red lights to green. Or, as they say on net.jokes: 186,000 miles per second: It's not just a good idea -- it's the LAW.
ajs@hpfcla.UUCP (10/13/83)
#R:rabbit:-202100:hpfcla:19900001:000:407 hpfcla!ajs Oct 11 11:38:00 1983 Speaking of blue-shifting red lights to green... I remember a story about someone arguing in court that they did not in fact run a red light, because it looked green to them at the speed they were travelling. As the story went, they snowed the judge and were almost let off the hook. However, a sharp prosecutor had the charge changed from running a red light, to speeding, and won the case.
mat@hou5d.UUCP (M Terribile) (10/17/83)
I have a feeling that no person who has any understanding of relativityu, either Special or General, would stoop to author an article to the audience of this newsgroup. (I don't claim to understand either, really) So I am going to present my understanding of one of the simplest paradoxes of relativity. Once you have absorbed the initial ramifications of it, perhaps we can begin to learn what this thing is all about. Consider a pair of devices. They are identical, and each has a light source on one end and an observer. Extending in front of the observer is a LONG rail with a series of mirrors. The source produces a pulse of illumination and the pulse is seen by the obserrver in each of the mirrors one after the other. This arrangement allows the observer to measure the speed of light. The first of these devices, with the name DOPPL stencilled in large letters on its side is standing in space in an inertial frame (no acceleration, no gravity). The second device, identical to the first except for the name GANGER stencilled in huge letters across one side, is hurtling so that it will pass alongside of device DOPPL, with their booms parallel. The observer on DOPPL measures (somehow) the speed of GANGER to be .98 * C and the observer on GANGER measures the speed (velocity if you want to talk fancy) of DOPPL to be .98 * C As the two devices pass, the light source on DOPPL flashes and BOTH observers, by noting the difference in delay times between reflections 1&2, 2&3, 3&4, etc, measure the speed of light. WHAT IS THAT SPEED? BOTH MEASURE EXACTLY C . PERIOD. So that there is NO WAY you could latch onto a photon and get pulled along. LIGHT ALWAYS TRAVELS (given a constant medium) AT THE SAME SPEED. NO MATTER HOW FAST YOU ARE GOING RELATIVE TO THE SOURCE OF THAT LIGHT. And you can NEVER travel as fast as light relative to any observer. In order for the speeds to work out, you have to perceive things SLOWER at greater velocity. Your clocks, including you, run slow. If you could reach light speed, everything would stop. You and everything in your from would be in suspended animation relative to the observer. And if you examine this situation you see it is impossible. It would, so to speak, require division by zero in physical laws. As usual, if anyone has reasonable credentials on the subject or has rigourous analysis to back him, I will stand aside or eat crow on this matter as appropriate. Mark Terribile hou5d!mat
skip@gatech.UUCP (10/17/83)
I've got a BS in physics and have done a little bit of work in relativity,
both special and general. I don't know if those are credentials or not,
but you are right about the speed of light being measured as c by both
GRANGER and DOPPL. As to the question of my speeding down the turnpike
at speed c and turning on my lights: The observer at the side of the
road would never see me do it because, in his reference frame, it will
take me an infinitely long time to do it. So he will never see the first
photon leave, much less measure it's speed. As for what I will observe,
I am no longer in the realm of taryons (sp? -- slower than light) so I
don't think of things as you do and the whole question doesn't make sense
to me.
By the way, I must have been born at the speed of light in order
to be going the speed of light. Not only do the laws (but I never went to
law school) prohibit me from going faster than the speed of light, they
prohibit from actually attaining the speed of light, although I can get
arbitrarily close. However things "born" at the speed of light can stay
that way, and things "born" faster than the speed of light can also stay
that way.
-- Skip Addison {emory,allegra}!gatech!skipbill@utastro.UUCP (William H. Jefferys) (10/31/83)
The best introduction to special relativity that I have seen
(I once used it with a class of non-science majors, very
successfully) is "Space and Time in Special Relativity"
by N. David Mermin (McGraw-Hill, I don't have the date).
In this book, Mermin derives all of the basic formulas from
first principles, using only high-school algebra, in a
very lucid and easily followed manner. He discusses the
"twin paradox" as well as other "paradoxes" of special
relativity. I think his discussion is simply the best
I've run across. I highly recommend this book.
Bill Jefferys 8-%
Astronomy Dept, University of Texas, Austin TX 78712 (Snail)
{ihnp4,kpno,ctvax}!ut-sally!utastro!bill (uucp)
utastro!bill@utexas-20 (ARPANET)rgt@hpfclj.UUCP (11/05/83)
#R:rabbit:-202100:hpfclj:14500002:000:224
hpfclj!rgt Oct 31 08:12:00 1983
No woman that I have ever known would be willing to tolerate the
infinite gestation of someone just to be born at light speed. Maybe
that is why this experiment has never been done.
Ron Tolley {hplabs!hpda!hpfcla!rgt}