Wayne Chirnside,
  In a message on 23 September, to Lee Lofaso, wrote :

WC> 
WC> I've heard physicists argue that time travel IS theoretically possible
WC> with our current understanding.
WC> 

Yes, I've read that too. As an object approaches the speed of light they'd 
appear to travel forward into the future. And IINM, once the object 
surpasses the speed of light, they'd start travelling backward.

And again, IIMN, the only "object" currently that travels faster than the 
speed of light is a tachyon. That may be how the theory came into being. 
Not sure though. Can anyone confirm the current theories on time? The book 
I read is probably outdated by now, as well as my memory.

Of course there are some major problems with a person travelling at those 
speeds. Having "inertial dampers," for one.

I think every single part of the "spaceship" would have to
"travel thru" 
time at the same rate. That may change depending on the weight of each 
part of the ship, and each object within the ship.

Also Gravity is a variable. I don't remember if it's a theory that Gravity 
affect Time, or that it's been proven as Fact yet.

If at some distant point in the future experiments were made to test these 
theories, it would be difficult to prove them. Or maybe not. I suppose the 
first few experiments would involve seconds or minutes. I think it was 
done with atomic clocks that were synched and showed a second to over a 
billion decimal places. Or that may be part of theory as well. If Gravity 
affects Time, then that experiment could very well have been performed 
using the fastest air vehicle that currently exists. If the clock was off 
by even a billionth of a second, it would prove something. Since even mach 
4 is just a fraction of the speed of light.

Anyone know the fastest speed that humans have achieved?

There are books on Time Theory, I got some of this info from it. 
Unfortunately I don't own it anymore
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