Nicole asked:

Time travel is an extremely interesting subject, but is it really conceptually possible?

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Absolutely not, but it makes for a great story line, which is why so many science fiction authors are
drawn to it. If you treat the subject seriously instead of as the basis for a science fiction story, you can
disprove the viability of time travel on two levels.

First, if time travel was possible, someone, at some point in the future, would have discovered how to
do it and visited the past. This hasn't happened (and remember, we're talking about the period from
now to the end of eternity for this to happen).

How do we know it hasn't happened? It's because of the second point. Life isn't a virtual experience.
If a time traveler inserts himself into a previous time, he ceases to become an observer of the past.
He's now a participant. Even if all he does is watch from a distance, he's taking up space, breathing
oxygen someone else was meant to breathe, diverting wind that formerly had no barrier to pass
through, and so on.

This may seem to be an insignificant consequence, but it is a consequence nevertheless. The
observer changed the past, thus altered history. That history is now different from the one he left, so
not only can he not return to his exact former "present", it may be that his former society (which
invented the time travel machine) no longer exists. If so, how did he travel to the past?

If you doubt the impact that a small, seemingly insignificant change can have on the future, know that
even a minute change in weather pattern computer models can produce radically different outcomes
days later. A slight breeze becomes a hurricane, or vice versa. Multiply this by a few centuries, and
the change could be overwhelming.

But it's always fun to play with the subject, which is why time travel stories will continue to remain
popular. Just don't put any real credence in them.

Phillip Ellis Jackson

www.sci-fi-jackson.com