Venus Radar Request, From Earth Options

[Decepticon]

I'm looking for earth based radar mapping of Venus.

I've had a hard time finding much. I clearly remember seeing images in books as a child.

Any help would be great!

[Guest_BruceMoomaw_*]

In reality, it wouldn't make a tinker's damn to Venus' chances of sustaining life whether it had a large moon or not -- its death warrant was signed the moment it formed close enough to the Sun to activate the "moist greenhouse" effect that stripped it of all its initial water and so allowed its volcanically released CO2 to build up and produce a huge blanket with a killer greenhouse effect.

Kevin Zahnle has an interesting new LPSC abstract ( http://www.lpi.usra.edu/meetings/lpsc2006/pdf/2359.pdf ) in which he claims that an Earthlike planet like Dune -- which started out with less water than Earth, but not NO water -- would actually be capable of sustaining a small biosphere much closer to the Sun than a planet which started out with a large water supply, because its moist-greenhouse effect would be minimal. However, he doesn't explain how that small initial amount of water could lock up most of the planet's CO2 in carbonate rocks, and thus why that planet wouldn't simply proceed to Venus' final fate much more directly. (Come to think of it, didn't we learn in the first Dune book that the planet actually had quite a bit of water overall, but the Little Makers sealed most of it off underground and prevented it from reaching the surface? If so, then before the Sandworms evolved -- since the Little Makers are their larval stage -- the planet must have been relatively wet and friendly. Kind of a reverse-Gaia effect.)

[Bob Shaw]

Bruce:

The Gaia effect - shorn of it's New Age mystical baggage - is just a handy catch all for homeostatic systems on a planetary environmental scale, so the Little Makers and the Sand Worms on Dune are simply ensuring that their environment suits their own needs, and in turn that environment has allowed them to fit it's paramaters. No real mystery there - except to the over-mystically inclined. Venus, however, is possibly a homeostatic system which has suffered catastrophic feedback and collapse to a more-or-less steady state which is quite inimical to life, and as such stands as a grim warning to us all regarding the changes we are wreaking on our own planet. Should we make the discovery of death (as opposed to the absence of life) on Venus then it should, I hope, have a profound effect on how we act here. I confess that I am rather concerned by our current effects on the Earth, not so much in terms of a few islands being drowned as a profound alteration to the whole environment (for example, as a result of clathrate decomposition in what was once tundra) and it'd be nice to have some changes made here and there before it's too late!

Bob Shaw

[AndyG]

Venus, however, is possibly a homeostatic system which has suffered catastrophic feedback and collapse to a more-or-less steady state which is quite inimical to life...

Perhaps on the surface - maybe not higher up the atmospheric column.

But that collapse of a system: is it due solely, as Bruce suggests, to the insolation received by the planet, or is it a deeper issue? If Venus had had a large Moon for example, and a higher rotation rate, and therefore more active tides and subsequent tectonic activity more akin to that of the Earth, wouldn't that have buried - sorry, sequestrated, to use the modern word ;-) - the excess CO2 efficiently?

The early Venus received 1800 watts per square metre compared to our 1380 today - that's not a huge difference compared to other locales in the Solar System. A spun-up Venus with a Moon might have been a suitable place for early life as well as the Earth.

(Perhaps I'm just hankering for the pre-probe SF Venus - dinosaurs wandering among the swampy jungles of our twin planet...)

Andy