if it were possible to travel the speed of light, I leave earth at 12
noon on a light speed ship. travel away from earth at the speed of
light for 5 minutes make a u turn, and get back at 12:10 , how much
time would I have lost or gained?

Hello riverdog,

The answer -- at least according to people who know much more about
physics than I do -- is that you would have gained 10 minutes (or,
more specifically, that a person standing on Earth would have aged 10
minutes, while you did not).

The formula for how much time would slow (or "dilate") for you is
expressed as follows (it looks much better on the original site):

Dt = g Dto 
where Dto is the proper time interval, or that recorded at rest
relative to an inertial reference frame
Dt is the dilated time interval 
g is the Lorentz factor 
g =[1 - (v/c)2]-1/2 

"The Special Theory of Relativity"
Home Page of Peggy E. Schweiger
http://www.cyberclassrooms.net/~pschweiger/relativity.html

As explained on another page, v is your speed, while c is the speed of
light (the same "c" from "e equals m c squared").

"The Twin Paradox in Special Relativity"
Ask a High Energy Astronomer
Imagine the Universe [NASA]
http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/971109a.html

The number for v, in your example, would be the same as c.  Thus, v/c
would be 1, and when you plug that into the equation, you end up with
the square root of 0, which is also 0.  Multiply 0 by the proper time
interval, and you get a dilated time interval of 0.  The dilated time
interval (for you) would be 0 minutes, while the proper time interval
(for someone standing on Earth) would be 10 minutes.

The sci.physics newsgroup has a detailed FAQ entry on this issue.  The
Introduction makes it clear that, according to the Theory of Special
Relativity, time does slow for the person traveling at or near the
speed of light.

"The Twin Paradox", by Michael Weiss
Usenet Physics FAQ (version date: 13th September 2002)
http://math.ucr.edu/home/baez/physics/Relativity/SR/TwinParadox/twin_paradox.html

- justaskscott


Search terms used on Google:

"speed of light" "round trip"
"speed of light" "twin paradox"

Don't forget that 1) no matter (like you) can travel at a speed
greater than OR equal to the speed of light in a vacuum   and 2) if
you could somehow travel at the speed of light and time really did
stop for you, you wouldn't be able to turn around (or
move/think/etc.).   If time's stopped for you, you aren't going to be
able to hit the brakes.

Does that mean that you can travel faster than the speed of light in air, IN AIR?

Yes.  And if you happen to be charged, you'll produce Cerenkov
radiation (light equivalent of a sonic boom).  If you've ever seen
pictures of fuel rods for nuclear reactors in water which appear to be
glowing blue, that's what's happening (particles moving faster in
water than light does in water).

Why exactly would you freeze if you traveled at light speed?
It's all relative. Time for you should stay the same up to
the speed of light. At light speed would be speculative.
It's the observer that sees you as frozen in time, not you.
Your watch continues to tick away at the pace you would imagine
it anywhere in the universe at any speed.
However, at light speed an observer might not see you at all since
length contracts, thus making you two dimensional. This is where
cartoons come from I think.
Your mass would also be infinite, thus the entire universe would
sucked into you.