Path: utzoo!attcan!uunet!nih-csl!jim
From: jim@nih-csl.UUCP (jim sullivan)
Newsgroups: sci.space
Subject: Re: Approaching c
Message-ID: <894@nih-csl.UUCP>
Date: 25 Jan 89 19:36:55 GMT
References: <Added.0Xr94Sy00Ui3IFME9H@andrew.cmu.edu>
Reply-To: jim@nih-csl.UUCP (jim sullivan)
Organization: NIH-CSL, Bethesda, MD
Lines: 35

In article <Added.0Xr94Sy00Ui3IFME9H@andrew.cmu.edu> CALVIN@JHUIGF.BITNET ("That's not lake Minnetonka...") writes:
>The argument (again, these are in simplistic terms, and I guess I should
>apologize.. 8^) ), unless I'm wrong, goes something like this:
>        An object becomes more massive the faster it travels.
>        Since F=ma (Newton), an accelerating body requires more and more
>             force to keep accelerating it
>        At (near?) c, this force would become infinite, and thus, acceleration
>             past c is impossible
>        THEREFORE, c is the highest attainable speed by an accelerating body.
>
>Ok. One thing screams out to me, though. c is a finite number, being 3x10^8 m/s
>which all of you know. Then, why would the force required to accelerate a
>body past c be infinite if c isn't infinite? How can it be assumed that a
>body will become infinitely massive at c if c itself is not infinite, UNLESS
>one assumes, subtlely, that c already is the fastest attainable speed (that
>is, c is in effect, infinite).

	Being a mathametician you must know that there are many 
	conditions where a limit exists which is never attained.
	I remember many equations where the curve gets closer and
	closer to some value but never attains it.  Also, relativity
	means that all things are relative to an observer.  An observer
	on a ship traveling at near c can accelerate and surpass c
	from his point of view.  He will however notice that his
	destination is now further away than he thought so to get
	say 5 light-years away, it will still take 5 years even though
	he continues to accelerate.
	Also note that relativity allows for matter to travel faster 
	than c.  You just cannot accelerate from below c to faster
	than c.  I remember a theory back in the seventies which
	proposed the existance of "tachyons" (FTL particles).  Don't
	hear much about them anymore.


						Jim