From: Marc Afifi (marc_afifi@yahoo.com)
Date: Wed Sep 20 2000 - 13:52:24 PDT
Message-ID: <20000920205224.11543.qmail@web215.mail.yahoo.com> Date: Wed, 20 Sep 2000 13:52:24 -0700 (PDT) From: Marc Afifi <marc_afifi@yahoo.com> Subject: Re: pinhole temperature of a vacuum
That is a great question, and here's a follow-up for
those of us past seventh grade who still don't
understand. If we imagine the sensitive thermometer
that Paul cites, then isn't the temperature that is
read by it really just the temperature of the
thermometer? In other words, the thermometer absorbs
radiation which excites its atoms/molecules which
jiggle the thermometer into reading 3K. But what is
the temperature of a photon? Is it the same as its
energy which, when measured, can be correlated to the
common conception of temperature? And if photons are
particles then doesn't their presence mean it isn't a
vacuum at all? I remember my cosmology professor
talking about photon pressure. Would we say that a
hypothetical vacuum with no electromagnetic radiation
has a temperature of absolute zero? And this reminds
me of Jay Goldberg's question about negative kelvins
which, to my best recollection, was not answered.
Anyone care to address that one?
Sorry, but once started I'm hard to stop. I love it
when students ask such thought provoking questions.
-Marc
=====
Marc Afifi
Chemistry, AP Chemistry, Physics
Pacific Grove High School
Pacific Grove, CA
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