Is it true that positrons run down the time, and electrons run up the time?
The short answer is no they don't. The origin of the idea of positrons
going one way in time and electrons going the other way comes from a comment
made by Richard Feynman. He said that a positron going forward in time
an electron going backward in time.
Feynman diagrams are diagrams used by particle
physicists to help them determine particle interactions. The graphic
on this page is an example of one. In them, one can draw what looks
like a particle going backward in time. That is not to imply that
they actually do! There has never been any observed case of
actual particles travelling backward in time.
Part of the problem comes from what is meant by the direction of
time. The consensus is that the forward direction of time is the direction
of increasing entropy. "Entropy" is a thermodynamic characteristic
applies only to systems of large numbers of particles. Roughly speaking,
entropy is the amount of disorder in a system. At the sub-atomic
level there is no entropy and therefore, no directionality
to time. So maybe positrons really are electrons going backward in
Submitted by Gougeon (Lyon, France)
(November 27, 1997)
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