ZEITREISEN - IAAC

They have determined that in part of space no time travel would be allowable, but in another part
(separated from the first by a surface called a Cauchy horizon) a time machine could be built, subject
to this restraint: if you build a time machine in the year 3000, you might be able to use it to go from
3002 to the year 3000, but not back to the year 1998 because that would have been before the
machine was built. Of course even this limited sort of time travel would be very difficult because you
would need a lot space-time warp for it to work, and this could only be provided through the agency of
a black hole or a decaying cosmic string loop. They also calculated that to move even one
microsecond back into the past would require the presence of a space-warping mass equal to one
tenth the mass of the Sun!
In addition, there is no guarantee the black hole wouldn’t swallow the time traveler and the space
around him. Then, as Gott says, the time traveler would be able to circle around and meet his earlier
self, but he would not be able to escape to boast about it. (Physical Review Letters, 1998, April 6.)
Note:
In the text Universe (with capital letter “u”) denotes “our” universe while universe (with small letter “u”)
refers to any of all other possibly existing universes.
Literature
John Sankey:What is Time?
Paul J. Nahin: Time Travel in Physics, Metaphysics and Science Fiction
Springer-Verlag, New York, 1993.
Michio Kaku: Hyperspace,
Anchor Books, New York, 1995.
Time travel discussion from John Gribbin
http://epunix.biols.susx.ac.uk/Home/John_Gribbin/Time_Travel.html
The Internet Movie DataBase
Zdenko Franic: The Colliding Universes and the Time Travel (in Croatian)
Time Travel (comments)
Presentation by Dr. Franic
At eight o’clock we went to the presentation hall and the project could start. Mr. Franic made a very
good computer presentation about how it is possible, or impossible, to travel in time and between
universes in physics. He started with the Big Bang and the begining of time. The next was explanation
of wormholes and the parallel worlds theories and other theories from many well known scientists,
such as Einstein, Rosen and others. He also showed us the hypothetical energy price of the time
travel ticket. The presentation was well prepared with many graphical explanations, so everybody
could basically understand the theory of travelling in time.
After the presentation we could watch the movie CONTACT, that worked with the idea to contact the
intelligent life in universe and to travel in time-space.
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ZEITREISEN 16. INTERNATIONALE PROJEKTWOCHE DES IAAC IN TANZENBERG