[net.physics] Traveling at the speed of light

CSvax:Pucc-H:ab3@pur-ee.UUCP (10/07/83)

   To dlg@philabs: 
	
	You are confusing the rest mass of the object (which determines
how much energy one may acquire by converting it to energy) with the
relativistic mass (which determines how much energy is required for
acceleration).

	Mathematically:

	Let M be the rest mass of the object.
	Let m be its relativistic mass.
	Let c be the speed of light.
	Let v be the objects' velocity.

	The Lorentz mass transformation states:
                      M
    m =     ____________________
                ________________
            __ /             2
             |/ { 1 - ( v/c )  }
      
	From this, we see that as v --> c, m --> oo.  So far, so good.

But the amount of energy available to us is:
               2
	E = M c 
           
which does *not* depend upon v; and is finite if M is finite, which I
sure hope it is.	

This boils down to trying to accelerate a rapidly-increasing mass with
a limited amount of energy...you can't win, and it doesn't matter what
your source of energy is, chemical *or* otherwise.

Darth Wombat