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From: oconnor@sungoddess.steinmetz (Dennis M. O'Connor)
Newsgroups: talk.politics.misc,sci.misc
Subject: Re: The Last Word on Friedman, Sevener, and Cuba
Message-ID: <9857@steinmetz.steinmetz.UUCP>
Date: 9 Mar 88 14:47:49 GMT
References: <3405@bloom-beacon.MIT.EDU>
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An article by orb@whuts.UUCP (45263-SEVENER,T.J.) says:
] Actually, I was not thinking clearly myself in this passage.
] The reason the Sun is refracted whereas day to day objects
] (including those seen over the sea) in air are not, is due to
] the change in density of the atmosphere at higher altitudes
] and the abrupt change to the vacumn of space.

There is NO "abrupt change to the vacuum of space", the 
atmosphere just gets thinner, and thinner, and thinner ...

] Cooper's text says this (p. 181):
] There is *no such thing* as an "index of refraction" for SeaLevel
] air.  There undoubtedly *is* some index of refraction for air at
] sealevel density versus air in the upper atmosphere, and of course
] there is *certainly* an index of refraction for an air-vacumn
] surface.

This shows a clear lack of undersanding as to what "index of
refraction" is. "Index of refraction" is a property derived from the
speed of light of the material referenced to the speed of light in a
vacuum. Even a vacuum has an index of refraction : 1.

Also, the idea that "SeaLevel" air doesn't have an index of
refraction is easy to disprove. Just look across a hot road someday.
The "heat ripples" you see are caused by the difference in the
refractive index of HOT vs. COOL "SeaLevel" air. Hold on
to this fact, it is important : the index-of-refraction
of air changes with pressure and temperature and humidity level.
In fact, increased pressure raises the index, increased
temperature lowers the index, and increased humidity
increases the index.

The property of "total internal reflection" may come into
play here. This property applies to light traveling
in a high-index material as it meats a low-index material.
If the angle is approach is close to tangential,
the light reflects off the interface as if it was a mirror,
and remains in the high-index material. Fiber optics
are based on this principle.

] Michael Friedman could not *possibly* have seen Cuba from Key
] West.  Mr. Carr, Mr. Swan, and others jumping in to attack
] me and defend Mr. Friedman's statement on the grounds that
] refraction makes it possible are all wrong.

Sorry, but if we postulate a layer of air at the correct
altitude that is less dense (certainly true), less moist
(not uncommon) and/or hotter (very possible over the ocean),
it is entirely possible that total internal reflection
will occur at the interface (even if gradual) to this
boundary, in effect creating a "mirror in the sky" by
which a person might indeed be able to see over the horizon.

] And I hope this teaches them all a lesson about "seeing
] what they want to see" and believing what they want to
] believe.

I hope this teaches you to be more thorough in your
scientific reasoning. This is NOT a personal attack.
But your "science" is TERRIBLE. 

] All I can say is: this particular exchange was one which may
] demonstrate to others on the net just who has credibility and
] who does not.
] Remember it in the future...
] 
] tim sevener  whuts!orb

Tim, seeing as you come off as pretty ignorant about optics,
atmospherics and science in general, these words of yours appear
particularly, well, ill-considered and ironic, perhaps.
--
    Dennis O'Connor			      oconnor%sungod@steinmetz.UUCP
		   ARPA: OCONNORDM@ge-crd.arpa
   (-: The Few, The Proud, The Architects of the RPM40 40MIPS CMOS Micro :-)