orb@whuts.UUCP (SEVENER) (03/25/88)
Earlier I pointed out to Mr. Leigh, the concept of "escape velocity" as described in a Britannica Micropedia article. Now I will cite a classic paper regarding the subject. In article <2177@mit-amt.MEDIA.MIT.EDU> dlleigh@media-lab.MEDIA.MIT.EDU (Darren L. Leigh) writes: >In article <3884@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.) writes: >> >>My, what a crop of scientific genuises we are training >>up at MIT!! > I suggested there might be an abrupt shift from the atmosphere > to space at the edge of the atmosphere. A poster has suggested > this is not correct. Personally I don't know. > Logically, it seems to me that there will be some kind of > abrupt shift or discontinuity at the point of escape from the > Earth's gravity. On the other hand, air is an amorphous gas > which is not rigidly bound and constantly in motion. So this > will blur the boundary. > >Isn't this rich? Obviously Tim hasn't heard Newton's law of universal >gravitation (F = GMm/(r^2)) or at least he doesn't understand it. >With Tim's understanding of physics at this level, I feel it best that >we ignore his postings on the subject for the time being. I repeat again: My, what a crop of scientific geniuses we are training up at MIT!! This issue, like many on the Net, has been hashed out a long time ago. George Stoney wrote a classic paper examining the content of the atmosphere at the edge of space, and for various planets and satellites. This paper was republished in the book, "A Source Book in Astronomy and Astrophysics, 1900-1975". Mr. Stoney correctly predicted many years before space travel the composition of gases in various planetary atmospheres. Anyway, let me note a quote from p.90 of "A Source Book": "...From this point upwards the density of the atmosphere will decrease by a much more rapid law, which will, within a short space, bring the atmosphere to an end." Got that, Mr. Leigh? "within a short space, bring the atmosphere to an end." Of course, I realize that the geniuses on this Net know better than the Britannica Micropedia or a source book on classic papers on Astronomy and Astrophysics, so I don't suspect this will persuade them. But there it is.... tim sevener whuts!orb
jfc@athena.mit.edu (John F Carr) (03/26/88)
In article <4010@whuts.UUCP> orb@whuts.UUCP (45263-SEVENER,T.J.)
writes an article perhaps more appropriate for rec.humor, and fails
to apologize to me for his accusations that I copied the magnitude
of refraction out of a book that I did not understand, despite the
fact that I derived that value (which Tim has admitted is correct)
in an article in this newsgroup:
: This issue, like many on the Net, has been hashed out a long
: time ago. George Stoney wrote a classic paper examining the
: content of the atmosphere at the edge of space, and for various
^^^^^^^^^^^^^^^^^^^^
What edge?
: planets and satellites. This paper was republished in the
: book, "A Source Book in Astronomy and Astrophysics, 1900-1975".
^^^^^^^^^
: Mr. Stoney correctly predicted many years before space travel
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
: the composition of gases in various planetary atmospheres.
You mean, Tim, that you are quoting as a source on the upper atmosphere
a speculative paper that was written before anyone actually measured its
properties? Can I quote in return from the classic work by J. Verne,
titled _From_the_Earth_to_the_Moon_ which makes many predictions of
conditions far above the Earth?
: Anyway, let me note a quote from p.90 of "A Source Book":
: "...From this point upwards the density of
: the atmosphere will decrease by a much more rapid law,
: which will, within a short space, bring the atmosphere to
: an end."
: Got that, Mr. Leigh?
: "within a short space, bring the atmosphere to an end."
The rest of us realize that this is not true. Certainly NASA would
be surprised to learn that it was impossible for Skylab to fall, or
for the orbit of the LDEF to decay.
At what altitude, Tim, do you claim that the atmosphere ends? Are you
aware of the fact that nowhere is there a true vacuum, and that the
Earth's atmosphere smoothly fades into the solar atmosphere (or solar
wind)?
: Of course, I realize that the geniuses on this Net know
: better than the Britannica Micropedia or a source book on
: classic papers on Astronomy and Astrophysics, so I don't
^^^^^^^
In other words, old. A lot of people know better now than did those
scientists. I once read a book on astrophysics written between
1900 and 1975 (closer to the earlier date) which speculated on
the energy sources of stars. Interesting reading, and rather
amusing to one knowing about nuclear reactions. Also now recognized
as wrong. It was about the best they could do with the knowledge
available. Similarly, without measuring the upper atmosphere, its
properties can only be guessed at. The guess posted by Tim is a
wrong guess. The scale height may decrease at high altitude (though
I suspect the opposite, since the temperature is so high: I'll check
the CRC) but the atmosphere does not end.
: suspect this will persuade them.
Tim: you refused to accept the astronomy references I used,
or the relevance of the fact that I am studying astronomy (and
astrophysics). Will you now do that? If you do not accept the
validity of my astronomy references on the grounds of irrelevance,
don't post your own.
I could also quote from the lecture notes of a course I am taking
on celestial mechanics, the current topic of which is low earth orbits.
We just spent several lectures examining the effects of atmospheric drag.
I am relieved to learn that the abrupt end of the atmosphere has made it
unnecessary to remember any of this.
A more appropriate source would be one of the standard atmospheres.
See, for example, the Handbook of Chemistry and Physics. ("But," I
hear Tim preparing to write, "that book is published by a corporation
so it must be biased.") That has extensive tables of atmospheric properties
to several hundred km altitude. If you look very carefully at the
tables (if the tables are too complicated for him, Tim can look at
the drawings instead) you will fail to notice any sudden drop in
pressure or density.
John Carr "No one wants to make a terrible choice
jfc@athena.mit.edu On the price of being free" -- Neil Peartsethg@athena.mit.edu (Seth Gordon) (03/27/88)
orb@whuts.UUCP (45263-SEVENER,T.J.) in <4010@whuts.UUCP>:
>My, what a crop of scientific geniuses we are training up at MIT!!
And in the *astronomy* department, no less. How can we expect a student
of astronomy at MIT to know *anything* about the "edge of space," let
alone enough to dispute Tim Sevener, whose credentials are... what were
those credentials, again?
I seem to recall an earlier posting, disputing Tim's belief in a
defininte atmospheric boundary, from someone at the Jet Propulsion
Laboratory.
My, what a crop of scientific geniuses we are employing at NASA!!
How dare they disagree with Tim Sevener, his encyclopedia, and his
"classic" sources! Perhaps you should subscribe to talk.origins, Tim,
and quote hundred-year-old arguments against evolution there. Clearly,
your talents are being put to waste here.
--
sethg%athena.MIT.EDU@mit-eddie.UUCP -- CONVERT me, CONTRA lovers! --
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