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Path: utzoo!linus!philabs!dlg
From: dlg@philabs.UUCP (Deryl Gaier)
Newsgroups: net.physics
Subject: Traveling at speed of light
Message-ID: <27349@philabs.UUCP>
Date: Thu, 6-Oct-83 16:22:37 EDT
Article-I.D.: philabs.27349
Posted: Thu Oct  6 16:22:37 1983
Date-Received: Sun, 9-Oct-83 17:37:24 EDT
Organization: Philips Labs, Briarcliff Manor, NY
Lines: 24

All of this recent talk about traveling at or near the speed of light
has reminded me of a question of mine that was never answered. I have
been away from the study of relativity long enough that I don't remember
a lot of the details, so maybe someone out there who is more familiar
with them can help me out. 
  My question has to do with traveling at or near the speed of light. I
have heard the argument that as your speed approaches that of light,
your mass also approaches an infinite value, thus you need an infinite
amount of energy to accelerate it. I can agree with this if the source
of energy is some type of chemical reaction such as is used to power the
present day spacecraft, since the energy released is primarily from
atomic bonds. Now to the point of my whole question (after I have bored
half of you silly!): Does this case still apply if the energy source for
the spacecraft is a mass to energy reaction (such as nuclear fusion)?
I would think that since the amount of energy released is proportional
to the mass that is "lost" in the reaction, that as the ship's speed
goes to infinity, the amount of mass "lost" in the reaction (and hence
the energy available to propel the ship) should also approach infinity.
Since these two quantities seem to be staying in the same proportion to
each other (thus giving the infinite energy required to continue
accelerating), why is there a limit to the speed which can be attained?
 Have I missed something in my line of reasoning, and if so what is it?
As I have said, I have been away from the subject for a while, so a
medium level discussion of this question whould be most helpful.