Are there active volcanoes on Venus? The latest results from ESA's Venus Express spacecraft have been taken by some scientists as firm evidence that there are, although others remain sceptical.
Venus Express measured a highly variable quantity of the volcanic gas sulphur dioxide in the planet's atmosphere: and while many firmly believe that this is linked to recent volcanic activity others argue that, because unlike on Earth there's no rain to scrub the atmosphere clean of sulphur dioxide, Express is detecting events that could have happened millions of years ago.
'We're only halfway through the mission, so we're not ready to say definitively one way or another on the basis of this evidence before we analyse all the data,' said Fred Taylor, a Venus Express Interdisciplinary Scientist from Oxford. 'However, there's plenty of indirect evidence for volcanic activity on Venus so, in my opinion, it's about how much activity is going on and the role it plays in the planet's climate. I think it's probably just a matter of time before we 'see' a volcano erupting.'
Because of their longevity in the atmosphere volcanic gases would have a much greater impact on the climate of Venus than they do on Earth: understanding their role in climate processes could help to explain how Earth's twin got a 'serious case of climate change'. Volcanism may also be behind the planet's cloudy weather as these are made of sulphuric acid, not water vapour.
Fred commented: 'It's still early in the life of the mission but if we can quantify the role volcanic activity plays in the climate it will help us to understand the global warming process on Venus and other planets, and how Venus - once so much like Earth - evolved into the hothouse planet it is now, and how it might change in the future.'