Since no one else took this up I will.
At 03:51 PM 2/26/98 -0500, Bill Hamilton wrote:
>I have heard objections to the canopy theory that are based on the claim
>that the environment under the canopy would be too hot to sustain life, but
>I'm not very familiar with the arguments used to support this claim. I
>suppose I really ought to get Glenn's CRSQ paper, but can you folks give me
>a summary? I can think of two reasons why it would be too hot: 1) If all
>the water in the oceans were in vapor form, the vapor pressure of water in
>the atmosphere would be significantly (and that's an understatement) higher
>than what we consider normal today. Higher vapor pressure requires higher
>temperatures, so it would be necessary for the temp to be higher; 2) The
>increased water vapor in the atmosphere would serve as a greenhouse gas
>which would trap more of the sun's heat.
The only issue I dealt with in my article was that of radiative transfer
which is the second of your reasons. The earth at today's surface
temperature radiates strongly at wavelengths between 10 and 12 micrometers
in the infrared region. Water vapor absorbs VERY strongly at those
wavelengths. So if you put lots of water vapor into the atmosphere, what
happes is that the temperature must rise to a point where the earth is
radiating strongly above 10 micrometers. In order to accomplish this, the
temperature must rise accordingly. The trouble is that such a temperature
makes life uncomfortable.
One can calculate this in another way. This is the roast in the oven
approach. If you place a roast in your oven, the hot walls transmit heat to
your cold roast. Similarly if you surround the earth in a high temperature,
high emissivity layer, the earth must be very hot. The base of Dillow's
canopy must remain above the condensation point for water vapor. Dillow
places 1.18 atmospheres of water vapor above the present atmosphere. This
means that the base of the canopy MUST be above 218 F or the canopy would
collapse. So, if you surround the earth with a layer of 218 F AND given
that such a layer would have an emissivity of nearly 1 the surface of the
earth must be at least 218 F. Emissivity is the percentage of blackbody
radiation that a layer gives off. Since no object is a true black body one
calculates the percentage of energy emitted compared to a blackbody and that
is the emissivity. A gas with the density and pressure of Dillow's canopy
would have emissivities around .9
glenn
Adam, Apes, and Anthropology: Finding the Soul of Fossil Man
and
Foundation, Fall and Flood
http://www.isource.net/~grmorton/dmd.htm