Re: [asa] Global Warming on Mars, Jupiter, Saturn, Pluto, Venus, ...?

>
> Mars is cold - 55 degrees below zero. A greenhouse effect on Mars would
> warm it up. The best way to get a greenhouse effect is through more carbon
> dioxide in the atmosphere. It appears that Mars is experiencing global
> warming. The ice patterns have been observed, with seasonal variations for
> many years. There is evidence of less ice. The ice has been believed to be
> largely carbon dioxide. If there is a solar system wide warming trend that
> is warming Mars, then it could trigger the formation of an atmosphere for
> Mars.
>
>
>
Mars has a very variable orbit, with substantial variation in the the
eccentricity (i.e., how circular it is), angle of the axis of rotation, and
direction of the axis of rotation relative to the orbit at a given point in
the orbit (Milankovitch cycles). The Earth has these wobbles, too, but the
relatively large size of the Moon helps moderate them. Even so,
the variation in the Earth's orbit are enough to cause significant variation
in climate (in interaction with all sorts of other factors). In particular,
the expansion and contraction of glaciers since the mid-Pliocene closely
matches these cycles. Mars is currently in a relatively warm phase;
however, it has been relatively warm for much longer than the recent,
dramatic warming observed on Earth. Even at its coldest, Mars has an
atmosphere, though not much of one by Earthly standards.

Pluto has a very elliptical orbit, coming closer to the Sun than Neptune for
some of the time. It is currently getting farther from the Sun and so
experiencing an overall cooling trend, hence the anxiety of planetary
astronomers to try to get a probe to Pluto before the atmosphere freezes in
a few years.

Even if global warming on Earth were primarily caused by solar factors, it
would still be stupid to ignore the potential aggravating effects of
human-caused change such as increasing greenhouse gases. In fact, it would
tend to suggest that we need to be even more agressive in controlling
greenhouse gas because the sun is working against us.

-- 
Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
To unsubscribe, send a message to majordomo@calvin.edu with
"unsubscribe asa" (no quotes) as the body of the message.