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Re: [Phys-l] slowing time



I think that the student may be thinking of what happens in hibernation or
refrigeration. It is certainly true that aging of a chemical or biological
sample should slow down, assuming that it can weather the freezing. So in a
sense time (aging) slows down for the sample.

I think there is some possible misconception lurking there in the student
question.

John M. Clement
Houston, TX

"A student asked if "time slows down as you approach absolute zero
temperature." I responded that the molecular vibrations decrease and
if you measure time according to that, then yes."


The question is tricky and a little ambiguous (at least I have a
problem trying to understand what the student meant when saying
"time slows down"). The amplitude and velocity of molecular vibrations
decrease with cooling, and in this sense the molecules slow down.
On the other hand, if there is a process that could be used as a
microscopic clock within an atom (e.g. the oscillating atom has a
radioactive nucleus), its decay rate increases when measured by the
laboratory-based observer. You can think of it as a rehash of the twins
paradox: one of the twins is stationary, the other is moving back and
forth together with the atom. With each cycle the moving twin comes
back having aged a little less than its stationary twin. If the atom
slows down, this time discrepancy decreases, that is the moving twin
starts aging faster. But of course this effect is ridiculously small
at low temperatures.