See below how Einstein came to the right result for the somewhat wrong reason.
You miss my point Nick - time dilation ruins the trip - too many years pass back on Earth and by the time you return all your friends you left behind are dead. With warpdrive and wormholes and assuming Hawking is wrong about chronology protection we don't have that problem. UFO evidence suggests that we do not live in the boring universe without time travel, warp drive and dark energy wormholes. Slower than light drives do not work fine because of time dilation and also the huge energy needed to get anywhere interesting in short proper time on the ship that will be long proper time back on Earth.
On Aug 23, 2010, at 5:17 PM, nick herbert wrote:
You don't need warp drive
to travel (subjectively) and return
faster than light.
Slower than light drives
will work just fine.
On Aug 23, 2010, at 5:05 PM, JACK SARFATTI wrote:
The problem with special relativity is time dilation in the last case you cite below. With warp drive, and if chronology protection is wrong, then we can go home again and return to our original time after a trip to the edges of our observable universe and beyond sandwiched between our future and past horizons.
On Aug 23, 2010, at 4:52 PM, nick herbert wrote:
On page 59 my book "Faster Than Light" I list 14 "things" that can go faster than light
including the ends of searchlight beams and the intersection of closing scissors. Of course none of these FTL "things" can be used for sending energy and/or information. It's my impression that the EM X-wave is closely analogous to the closing scissors. Also it has long been realized that the travel velocity as seen by inhabitants of a space ship traveling at near-light speeds can be many times light speed and (courtesy of relativity) it would be possible to complete a journey of hundreds of light years in a few (subjective) weeks.
On Aug 23, 2010, at 3:18 PM, JACK SARFATTI wrote:
On Aug 23, 2010, at 1:52 PM, Erasmo Recami wrote:
as to the problem of "precursors" (which, incidentally, can be the
ones with the lowest speed, instead of the largest speeds, as you can easily demonstrate), let me add a paper, attached here with as the
second (last) paper.
The 1st attachment contains the initial two (introductory)
chapters of our recent J.Wiley (2008) book on Localized
Waves (super- and sub-luminal)
Thanks for any attention from you and /or your correspondents
On Sun, 22 Aug 2010, JACK SARFATTI wrote:
OK Waldyr, but as I read in a bit more detail you never claim actual superluminal energy transport or signaling in violation of traditional signal locality. You have a finite aperture space-time limit pulse with dispersion and the front is always limited to c it's only a central peak that is FTL for short time until peak catches the front where it is trapped - correct?
Begin forwarded message:
Date: August 23, 2010 1:46:46 PM PDT
Subject: Re: Waldyr Rodrigues's "Superluminal" X EM Wave (Dr. Quantum)
Many answers to the comments contained in your last email can be found
in my homepage www.unibg.it/recami , and in the review article on
X-shaped localized waves, that I want to put at your disposal, and at
the disposal of the colleagues you'll kindly contact.
Finite-energy solutions have been mathematically contracted,
and experimentally constructed, since MANY years, both as exact
solutions, and as mere approximate solutions by space-time
truncation (the big expert being Michel Zamboni-Rached)
In recent times we worked especially about localized solutions
not super- but subluminal (they are know to exist with any
group-velocities, from zero to infinity), and in particular
on the ones "at rest" (with static envelope) that we called
Frozen Waves, and promise to have the greatest applications ("Bracco Inaging" wanted to Patent them...)
I just came back from Rio de Janeiro
On Sun, 22 Aug 2010, JACK SARFATTI wrote:
However, before we get too excited traditional retarded causality excluding both faster-than-light signals and faster-than-light propellant escape speeds is not violated it appears because Waldyr wrote:
(iii) Is it possible to build a physical device to launch a finite energy
superluminal electromagnetic X pulse? Our answer is no. Indeed, finite
aperture approximations (FAA) to exact superluminal X-like solutions of
Maxwell equations (which, of course have finite energy) have already been
produced [7,8]. However, these FAA are such that their peaks move with
velocity v > 1 but their front always moves with the speed of light. This
result has been predicted in [16,18] and is endorsed by the experimental
results of [7,8] as proved in . Now, concerning the solutions we just
found, in order for them to be produced (by an antenna) as real physical
waves it is necessary to produce waves that extend in all the z = 0 plane
where the antenna is located for the time interval -T < t < T. Of course,
this is physically impossible because it would require that the antenna should
be an infinite one.
(iv) Besides the superluminal solutions just found, there are also finite
energy subluminal solutions (to be reported elsewhere). We must say that
even if the new superluminal solutions cannot be produced by physical devices
the only possible reason for their non existence in our universe is that
of a possible violation of the principle of relativity. Eventually these new superluminal
solutions may also find applications in the understanding of some
fundamental issues concerning the nonlocality problem in quantum mechanics
Finite Energy Superluminal Solutions of
E. Capelas de Oliveira1*and W. A. Rodrigues, Jr.2+?
1 Institute of Mathematics, Statistics and Scientific Computation,
CP 6065, 13083-970, Campinas, SP, Brazil
2Department of Mathematics, University of Liverpool
Liverpool L69 3BX, UK
February 5, 2008
On Aug 22, 2010, at 9:18 AM, JACK SARFATTI wrote:
Begin forwarded message:
Date: August 22, 2010 3:22:29 AM PDT
Subject: RES: Yakir Aharonov's book Quantum Paradoxes - Note #1 (Dr. Quantum)
In your note you state: " ...although a spatially oscillating electromagnetic radiation far field at rest does not exist in Maxwell's classical field equations...."
Well, in the summer of 1997 I found some extraordinary sub and superluminal solutions of the free Maxwell equations. In particular I found a solution that can be at rest in a given inertial frame (there are infinite number of solutions of this kind, contrary to a famous Einstein statement...). In that solution E?B! One of my students called that solution the Jedi sword. You can see how I found that solution on page 16 and sequel (see Eq.(3.19)) the attached paper (upwlast1.pdf), which has been originally published in Found. Phys. 27 435-508 (1997).
In reading the paper take notice that I changed my mind concerning some issues discussed there, as it is clear from other papers I wrote on the subject and which are also attached here. I am preparing (since a long time ago) in my free time a book on the subject.