[ExI] Global Temperatures to Decrease

Damien Broderick thespike at satx.rr.com
Sun Apr 20 23:34:02 UTC 2008

At 04:04 PM 4/20/2008 -0700, Spike wrote:
> > http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html )
> > >which causes the earth to radiate heat into space as a
> > >function of the fourth power of the temperature...
> >
> > And yet, strangely, this law is apparently unknown on Venus.
> >
> > What am I missing? (Yeah, it's closer to the Sun; and?)
>Ja, you didn't miss anything, the radiation law is well known on Venus.  It
>is closer to the sun, and the energy received varies as the square of the
>distance, so about .7 AU translates into durn near twice the solar energy.
>The very thick atmosphere there does trap a lot of energy.  The atmospheres
>on the planets are not directly comparable  (93 bars vs 1 bar).

My impression is that Venus's heat-trapping atmosphere is the key. 
I've seen it argued that if the Venerian atmosphere could be thinned, 
terraforming the surface might become feasible, despite the greater insolation.

>In any case I don't think the global warming crowd is suggesting a mechanism
>for runaway warming thru increased amount of atmosphere

Surely it's their very case--if "increased amount" is read as 
"increased heat-trapping constituents of the atmosphere," 
significantly due to human activity--coal burning, farting or 
belching cows, etc.

Damien Broderick

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