Suppose I had a clock whose ticking rate was temperature dependent -ie., it
runs faster at higher temperatures. If I traveled with this clock to a
higher temperature region, the clock would speed up, but I could not claim
to have traveled faster into the future. Now we find that clocks are
gravity dependent. But the big difference is that not just some clock, but
ALL clocks, and ALL processes (eg., your heartbeat) are gravity dependent.
It would seem that sanity would be better served by simply saying just that,
instead of claiming to have traveled into the past or future - or speaking
of "time travel" or slowing down or speeding up "time". For example, the
fact that all change is gravity dependent offers no mechanism for travelling
into the past and changing events - avoiding all the logical difficulties
inherent in a real "time travel" claim.
Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
treborsci@verizon.net
www.sciamanda.com