Venusian datafest in Nature

Anyone interested in Venus will be very happy with this week’s issue of Nature, which has published a raft of papers detailing the latest findings of the European Space Agency’s Venus Express probe, which has been orbiting our inner planetary neighbour for the last 19 months. Even better, they’re freely accessible to all.
The papers are focused on the composition and dynamics of Venus’ atmosphere, which is hardly an area where I can claim expertise. Fortunately, the major findings have been nicely summarized by Svedhem et al., who come to a rather interesting conclusion:

The overall sense of the results from the first year of operation of Venus Express is that the differences, particularly in climate, between Venus and Earth are much less mysterious than previously thought after the early phase of spacecraft exploration.

In other words, although Venus is quite decidedly not like Earth, most of the differences we see in atmospheric circulation patterns which initially seem quite weird, such as double polar vortexes, are actually comprehensible, and follow on logically from the obvious differences – an atmosphere composed almost entirely of carbon dioxide, no geomagnetic field to speak of, and a very slow rate of rotation (243 days for each turn on its axis).
Of course, I’m not so much into atmospheres as the planets beneath them, so I was interested by this excellent accompanying article discussing the prospects for new missions to study the surface. For anyone interested in tectonics like me, what we know about the Venusian surface (thanks mainly to Magellan’s radar imagery) is rather perplexing. As far as we can tell, it is not being shaped by any process resembling plate tectonics: despite Venus being so similar to the Earth in terms of size and composition, and therefore probably in possession of a convecting silicate mantle, we see no evidence of rift or subduction zones. Yet, at the same time, the Venusian surface seems remarkably free of craters, suggesting that the surface is quite young. Where does the new crust come from? Where does the old crust go? No-one really knows – and finding out would probably tell us something pretty fundamental about the processes that shape our own planet. Sadly, without even a whiff of a prospect of finding life of Venus, funding will probably be hard to come by, so we may have to wait a while.