time travel - the same old thing

I just recently read the article "A Class of Time-Machine Solutions
with a Compact Vacuum Core" from physical review letters, published on
july 7th. I must say I didn't understand most of it and I have some
questions. Not questions about the article itself, which I would need
to read much more stuff than you can probably teach me in one news
post (if someone knows sites that could help me out I'd be thankful),
but questions about the simple time travel idea.

Does that paradox about the guy that goes back to the past and kills
his own father before he was born have any workaround? What I could
understand from the article is that is theoretically possible to go
back in time, doesn't it mean that the theories that allow that have
some kind of flaw? After all, going back in the past leads to a
paradox, doesn't it?

[]'s
Rafael

Dear Rafael Almeida:

"Rafael Almeida" wrote in message
...
I just recently read the article "A Class of Time-Machine
Solutions with a Compact Vacuum Core" from physical
review letters, published on july 7th. I must say I didn't
understand most of it and I have some questions. Not
questions about the article itself, which I would need to
read much more stuff than you can probably teach me
in one news post (if someone knows sites that could
help me out I'd be thankful), but questions about the
simple time travel idea.

Does that paradox about the guy that goes back to the
past and kills his own father before he was born have
any workaround?

Several. Multiple Universes. Or Nature's way, preventing
backward time travel altogether.

What I could understand from the article is that is
theoretically possible to go back in time,

No, it is not theoretically possible. It is SciFi. A theory
implies experimentally falsifiable prediction.

doesn't it mean that the theories that allow that
have some kind of flaw? After all, going back in
the past leads to a paradox, doesn't it?

Several. Conservation of Energy, Pauli Exclusion. And strictly
going back in time (or forward discontinuously) will leave you
floating in the depths of space, since the Earth has a velocity
of 300 km/sec. So the Earth would be somewhere else when you
arrived.

David A. Smith

Rafael Almeida wrote:
I just recently read the article "A Class of Time-Machine Solutions
with a Compact Vacuum Core"

Perhaps the reliance on a "Compact Vacuum Core" is because you need to
be a big sucker for this to work?