Discussion and news about the modern effort to understand the nature of life on Earth, finding planets around other stars, and the search for life elsewhere in the universe

Monday, May 3, 2010

Active Venus

Venus is by any terrestrial standards a pretty rotten place for life. With a massive greenhouse atmosphere pushing the surface temperature up to over 800 F, and a crushing pressure 92 times that on the Earth's surface, it has long been held up as a poster child for an terrestrial-type planet gone awry. Of course that's a great simplification and probably the wrong way to characterize it. Nonetheless, it has certainly seemed that Venusian geophysics do not give rise to the kind of long-term regulatory processes that we seem to have on Earth - such as the carbon-cycle. Indeed, the common lore has been that Venus exhibits none of the volcanic activity that we see here on Earth, and that it is locked into a fundamentally different state whereby only rare and catastrophic upheaval resurfaces the planet (almost literally turning the crust inside out).

This situation would predict a certain release and cycling of gas components into the atmosphere, and control various aspects of long-term climate. Now a new study by Smrekar et al, using visible and infrared imaging data from Europe's Venus Express orbiter has indicated that this received wisdom may be wrong. Combining the better topographical measurements with spectral analyses of composition seems to have robustly identified a number of geophysical 'hotspots' on Venus, with vast areas of 'flow' or younger material, perhaps only a few tens of meters thick and likely only a few tens or hundreds of thousands of years old.

In a nutshell, Venus may be geologically active today, and with a near surface structure of hot plumes of rock not at all dissimilar to those of the Earth. So perhaps our sister planet is not as different as we suspected....

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