An improved version of this post has been submitted for publication in a book, so this post had to be removed. The book, soon to be published, is:
Charles R. Anderson, Ph.D. is a materials physicist, self-owned, a benevolent and tolerant Objectivist, a husband and father, the owner of a materials analysis laboratory, and a thinking individualist. The critical battle of our day is the conflict between the individual and the state. We must be ever vigilant and constant defenders of the equal sovereign rights of every individual to life, liberty, property, self-ownership, and the personal pursuit of happiness.
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28 September 2010
NOAA's U.S. Standard Atmosphere Tables of 1976: Who Needs Greenhouse Gas Warming?
An improved version of this post has been submitted for publication in a book, so this post had to be removed. The book, soon to be published, is:
Thanks for your post, I read it while it was available and it was really interesting. The problem of the temperature distribution of a gas under the force of gravity is really mindboggling. I found the following passage in an old book on the history of statistical mechanics entitled "The kind of motion we call heat":
ReplyDelete"...According to Herapath, the force of gravity by itself produces a temperature variation in a vertical column of air, namely a decrease of about 1 F for every 100 yards increase in height above the earth's surface (assuming perfectly dry air); the 'total altitude of the air' would thus be approximately 31 miles, if it terminates when the temperature has dropped to absolute zero.
Herapath's work was refused publication by the Royal Society of London but seems to have had ample publicity through its appearance in several issues of the Annals of Philosophy...."
Today we know that the atmosphere extends to much higher altitudes than 31 miles and that the temperature is stratisfied above approximately 11 km altitude. However, the problem formulated back then is almost forgotten today. The only prevailing theory for the drop in temperature with altitude is the "greenhouse effect", but the latter is never mentioned in the physics literature.
Since i presume you have much more knowledge than me in experimental physics I have a question I would like to here your opinion on.
Postulating an isothermal column of air, the density decreases according to the barometric formula. However, the barometric formula holds in an infinite space domain which means that we can consider the air to move freely in space and even have a remote but theoretical possibility to reach the surface of the moon if some molecules are given sufficient kinetic energy. Now suppose that you stand on the surface of the moon with a thermometer. Formally you are still in the atmosphere of the earth but what temperature will you measure?
In other words, have you thought about the CRITICAL DENSITY, when our thermometers no longer give an accurate measure of the temperature of the gas. This question is somewhat philosophical so don't hesitate to speculate, I'm just curious to hear somebody else's opinion about this.
Regards
Anders