Mankind’s
Explanation: Wormholes
“Wormhole: A
thin tube of space-time connecting distant regions of the universe.
Wormholes might also link to parallel or baby universes and could provide
the possibility of time travel.
The idea of wormholes between different regions of space-time
was not an invention of science fiction writers but came from a very respectable
source.
In 1935, Einstein and Nathan Rosen wrote a paper in which
they showed that general relativity allowed what they called “bridges,” but
which are now known as wormholes. The
Einstein-Rosen bridges didn’t last long enough for a spaceship to get through:
the ship would run into a singularity as the wormhole pinched off.
However, it has been suggested that it might be possible for an advanced
civilization to keep a wormhole open. To
do this, or to warp space-time in any other way so as to permit time travel, one
can show that one needs a region of space-time with negative curvature, like the
surface of a saddle. Ordinary
matter, which has a positive energy density, gives space-time a positive
curvature, like the surface of a sphere. So
what one needs, in order to warp space-time in a way that will allow travel into
the past, is matter with negative energy density.”
Information acquired within the
quotes is from: A Brief History Of Time, Stephen Hawking, pages 164, 204,
copyright 1996, published by Bantam Book