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<DIV><FONT face=Arial size=2>SO..... in other words... Newtons theory about the
apple falling on his head about sums it up.... right?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>WG</FONT></DIV>
<DIV> </DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=randy10926@comcast.net
href="mailto:randy10926@comcast.net">randy10926@comcast.net</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, August 15, 2005 4:35
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Why doesn't the sky
fall?</DIV>
<DIV><BR></DIV>
<DIV> At the top of a planet's atmosphere,
particles are running around in all directions, at all of the various speeds
corresponding to the kinetic temperature, and to the predictions of the
Maxwell-Boltzmann distribution. Some of the particles will be headed upwards,
some downwards, and some sideways. Some of them will be moving slowly, some at
an average speed, and some very quickly. Whether a planet will hold onto an
atmosphere will depend upon the motions of those particles which happen to be
moving upwards at a much higher than average speed. If those particles are
moving upwards at less than the planet's escape velocity (the speed which an
object must be traveling at in order to escape the planet's gravity, and go
off into space), then the particles will follow curved paths which are
ellipses with a focus at the center of the planet, and will go up for a while,
and then fall back into the atmosphere. (This discussion assumes that we are
in the very outermost reaches of the atmosphere, where there is so little gas
that the particles don't collide with other particles very often. If we were
talking about a lower region, the particles would be deflected from their
paths, and change their energies, so frequently that any discussion of motions
which resemble orbital motions would be
pointless.)<BR> However, if the particles were
moving upwards <B><I>faster</I></B> than the planet's escape velocity, they
would follow hyperbolic paths which would take them out into space, never to
return. Of course, only those particles which happened to be heading upwards
at very high speeds would follow such paths, but as already discussed, there
is a continual shuffling of particle motions and speeds, and as a result, in a
short while, particles which did not originally have such motions would end up
with motions identical to those particles which had been lost, and then those
particles would also be lost.</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>Simple ain't it.</DIV>
<DIV> </DIV>
<DIV>Randy</DIV>
<DIV> </DIV>
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<DIV><FONT face=Arial size=2>I thought it was time to stir the pot
while we wait for the results from the Worlds.</FONT></DIV>
<DIV><FONT face=Arial size=2>Can anyone explain why gravity doesn't pull all
the air molecules down to earth? Are they lighter than space?
What is their mean speed?</FONT></DIV>
<DIV><FONT face=Arial size=2>I don't think this will help answer the
weathervaning question and won't help us fly any better but I thought it
might be fun.</FONT></DIV>
<DIV><FONT face=Arial size=2>Jim
O</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>