I don't think you mean to say that its mass would
increase. Just as an astronaut traveling into space feels a perceived increase in weight but
the astronauts mass remains the same. I belive in
all these instances it is gravity not light energy
that has a profound effect on matter. Another thing to think about as far as time travel goes
is matter can be neither created or destroyed
so the amount of matter in the universe must
always remain constant. So if time travel is even
remotely possible. It would have to involve something other than what we know as normal matter



Later Edward