Non-Identical Twins

Not quite Venus! Somewhere nice in Aussois, France (image Maurienne-tourisme)

We may have to wait a bit before we have samples from Venus (see last entry), but that doesn’t stop us finding out a lot more about our twin planet, thanks to ESA’s Venus Express probe. Twin planet! Well I guess that’s pushing it a bit. Venus is our nearest neighbour in the Solar System (minimum distance from the Earth 40 million kilometres, compared to about 60 million kilometres to Mars). The Earth and Venus are about the same size, have similar average densities and probably fairly similar bulk compositions (although we don’t know that for sure). But that’s about as far as the similarities go. Venus has an average surface temperature of 462°C, a surface pressure 90 times that on Earth and an atmosphere largely composed of carbon dioxide, with clouds formed of sulphuric acid droplets. Not a fun place.

Launched in November 2005, Venus Express arrived at its destination in April 2006. The principal objective of the mission is to understand the long-term dynamics of the Venusian atmosphere. In view of its size and mass, Venus should still be volcanically active, but this has never been directly confirmed. However, using data collected by Venus Express, a recent report in the journal Science gives details of young volcanic areas that probably formed as little as 250,000 years ago. Venus Express will be joined in December of this year by the Japanese probe Akatsuki, which is specifically designed to look for changes in Venus’s atmosphere and surface, including any associated with active volcanism on Venus.

And so, in view of the horrific nature of the Venusian climate, you might imagine that the recent International Venus Conference would be held somewhere like Death Valley, or the middle of the Gobi Desert. Not at all, it was held in the lovely French ski resort of Aussois (See photo above). The choice of venue was justified by one of the organisers with the throw away lines: “We had to pick somewhere” and “It’s a nice place to be”. Unlike Venus. The conference was discussed on a recent edition of BBC Radio 4’s excellent programme: The Material World. The programme also featured Dr David Rothery of the Open University discussing recent results from the Venus Express mission with the programme’s consistently entertaining presenter Quentin Cooper. Dr Rothery, who chairs the Open University’s level 1 and level 2 planetary science courses, specifically drew attention to the importance of the Venus Express data in demonstrating that, like Earth, Venus is almost certainly volcanically active. So perhaps they are twins after all.

Link: The Material World (24th June 2010)

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