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The Question
(Submitted June 12, 1997)
My question comes as a result from reading "About Time" by Paul Davies.
In it he talks of time travel and other such things.
How can one prove the existence of tachyons
and once it is proven, can they be implemented for space
travel like in Star Trek (i.e. faster than light space
travel)?
The Answer
Probably two of my favorite popular level treatments of the possible
technological implications of tachyons are:
"Future Magic: How Today's Science Fiction Will Become Tomorrow's Reality"
by Dr. Robert L. Forward, Avon Book, 1988.
and
"Faster Than Light: Superluminal Loopholes in Physics" by Dr. Nick Herbert,
Plume Books, 1988.
Personally, I think Bob Forward's is the better of the two.
As to proving the existence of tachyons, one basically has to discover a
particle interaction which can *only* be explained by the presence of one
or more tachyons. Some theoreticians argue that if tachyons exist, the
universe could be filled with them but they interact so weakly with
ordinary matter that we can't detect them. Physicists have searched
through some experimental records and so far none of the high-energy
accelerator labs have detected an interaction which can *only* be explained
by tachyons. This means that tachyons must be far more weakly interacting
than neutrinos. If they do exist, tachyons would be extremely difficult to
utilize under our current understanding of physics.
You could travel faster than light if you could turn yourself (and your
starship) into a tachyon. However, special relativity indicates that if
you did this, you could travel back in time and violate causality - the
idea that causes must precede their effects. You could wind up in the
"Grandfather Paradox": What if you go back in time and kill your
grandfather before your father is born? But if you're never born, how
could you go back and kill your grandfather?
There seems to be a lot of bogus science on the Web surrounding the subject of
tachyons. A number of companies seem to like the name in their product so be
careful what you read.
Tom Bridgman
CGRO Science Support Center
for Ask an Astrophysicist
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