Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 5/3/83 based; site hou2g.UUCP
Path: utzoo!watmath!clyde!floyd!harpo!ulysses!mhuxl!houxm!hou2g!stekas
From: stekas@hou2g.UUCP (J.STEKAS)
Newsgroups: net.physics
Subject: Re: Entropy, Gases and fluctuations.
Message-ID: <207@hou2g.UUCP>
Date: Thu, 22-Mar-84 15:58:15 EST
Article-I.D.: hou2g.207
Posted: Thu Mar 22 15:58:15 1984
Date-Received: Fri, 23-Mar-84 21:03:22 EST
Organization: AT&T Bell Labs, Holmdel NJ
Lines: 23

Sure it's possible for all the gas in a room to find itself
in one corner - it's called a "fluctuation".  It's easy to
calculate the probability of such a fluctuation ...

Say the room has a mole of particles (10^23) and we want to find
out the probability that all the particles find themselves in a
sub-volume which amounts to 10% of the total volume.  Now the
probability for a given particle to be in that small volume
is 0.1, so the probability that ALL of them would be in that small
volume is

                                      23
                                  (10    )
                          p = 0.1


                                                       23
Now this number is not of order of magnitude 23, but 10  .  That means
10^23 zeros to the right of the decimal point!  I think that this is
about as "unlikely" as anything one can imagine, considerably less likely
than finding a Unicorn in your garage tomorrow.

                                                 Jim