ESA Venus Express: Clues Point to Active Volcanoes

New evidence hints that Venus may be volcanically active, which has long been a controversial topic among scientists.

Six years of observations by the European Space Agency's Venus Express spacecraft have shown significant changes in the sulphur dioxide content of the planet's atmosphere over time, which could be explained by a bout of volcanism.

Immediately after arriving at Venus in 2006, the spacecraft recorded a significant increase in the average density of sulfur dioxide in the upper atmosphere, followed by a sharp decrease, according to a release from the European Space Agency (ESA).

Venus' atmosphere contains much higher levels of sulphur dioxide than on Earth. On our planet, the smelly, toxic gas is produced by volcanoes.

Sulphur dioxide doesn't last long in Venus' upper atmosphere, because it is broken down by sunlight. Any sulphur dioxide in the upper regions must have recently arrived there from the thick protective clouds that swirl beneath.

Some scientists think that the spike in sulphur dioxide suggests that a large volcano, or several volcanoes, must have erupted.

Venus is covered in hundreds of volcanoes, but whether they remain active today is much debated, and settling this question is an important scientific goal for Venus Express.