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Published online 27 November 2007 | Nature | doi:10.1038/news.2007.297
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European mission reports from Venus
Venus Express, the first European mission to Venus, finds evidence for past oceans.
Two years after Venus Express left a launch pad in Kazakhstan, the first European mission to Earth's ‘evil twin’ is turning up results.
Scientists today publish a suite of eight papers in Nature1-8 reporting the first observations from the craft, which arrived at Venus — the second closest planet to the Sun and Earth’s next-door neighbour — in 2006.
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Dear Sirs: I would like to suggest that the conclusions of how Venus became a hot house needs to be tempered. (I'm sorry I do not have relevant references at hand but hope you will take these comments under advisement and use em for improving your thesis). Rather, there is no evidence that oceans ever established themselves on Venus. In fact some of us believe that outer crust turns over catastrophically leaving very little trace of the old crust on Venus. This is not a reason for heat but rather evidence for the lack of evidence of the ocean. Perhaps the effect of the not having strong radiation belts is the secondary cause for the run-away hot house. Thus a factor you've stated but glossed over in your article is quite a bit more important. The reason for the lack of radiation belts is lack of solid core and dynamically convecting mantle. And coincidentally Venus lacks a moon and thereby lacks tidal forces to really drive and accentuate the equivalent of van der-waal radiation belts. Thus the lack of a moon, which the earth has had for at least 3 billion years, is the primary reason for the hot situation there. So if Venus never had good protection from the radiation of the Sun, water may have always been heated into vapor and blown away into space. Without sufficient water being returned or recycled into the mantle, the mantle would slowly dry up requiring or resulting in hotter temperatures for a dry solidus in the equivalent of an asthenosphere. These ideas are all published reputable journals, but perhaps a sparse grid of sturdy seismometers are required to develop a picture of the mantle in order to understand the Venus atmosphere. Sincerely, Joshua C. Turner
Dear Sir I am a little bit surprised how the problem of the possibility of past oceans of liquid water on Venus is so confidently reported with so poor information. It seems to me that the reason why liquid water never existed on Venus is related to the high abundance of CO2, a closer distance to the Sun than from the Earth and, at the start a strong greenhouse effect. After all, and contrary to what seems implied in the news from Eric Hand, liquid water and a good temperature can transform CO2 in carbonates without the help of living processes. The idea expressed by Fred Taylor that "Venus is a twin Earth that has just taken a different evolutionnary path" is a very surprising statement. What is revealed to us, on the contrary, is that a twin planet with sligthly different initial conditions does completely diverge in its evolution, relative to that of the Earth. This may indeed be a very bad sign for the occurence of life on any other planets in the Galaxy. If, given so sligthly different initial conditions, the evolution can be so ferociously different on Venus (as on Mars) than on Earth, then life as we know it may be a very rare chance in the Universe. Solar System bodies (planets and so many satellites) have all been formed more or less at the same epoch and from the same molecular cloud and starting material. Yet on this relative "infinity" of worlds, only Earth seems not only hospitable but still maintaining life. This evident lesson should not be forgotten to people who love and live on ou unique so unique planet. Dr. Louis d'Hendecourt