Evidence Suggests Venus Has Active Volcanoes

Tue, 12/04/2012 - 12:47pm

Artist’s impression of an active volcano on Venus. Results from a long-term study of Venus find evidence of a clear injection of sulfur dioxide into its upper atmosphere. One possible interpretation is that volcanic activity increased the sulfur dioxide component of the upper atmosphere, although an alternative is that a change in atmospheric circulation dredged up the gas. Image: ESA/AOESSix years of observations by ESA’s Venus Express have shown large changes in the sulfur dioxide content of the planet’s atmosphere, and one intriguing possible explanation is volcanic eruptions.

The thick atmosphere of Venus contains over a million times as much sulfur dioxide as Earth’s, where almost all of the pungent, toxic gas is generated by volcanic activity.

Most of the sulfur dioxide on Venus is hidden below the planet’s dense upper cloud deck, because the gas is readily destroyed by sunlight.

That means any sulfur dioxide detected in Venus’ upper atmosphere above the cloud deck must have been recently supplied from below.




Now, an analysis of sulfur dioxide concentration in the upper atmosphere over six years provides another clue.  



At that time, the preferred explanation was an earlier injection of sulfur dioxide from one or more volcanoes, with Pioneer Venus arriving in time for the decline.

“If you see a increase in the upper atmosphere, you know that something has brought it up recently, because individual molecules are destroyed there by sunlight after just a couple of days,” says Emmanuel Marcq of Laboratoire Atmosphères, Milieux, Observations Spatiales, France, and lead author of the paper published in Nature Geoscience.

“A volcanic eruption could act like a piston to blast sulfur dioxide up to these levels, but peculiarities in the circulation of the planet that we don’t yet fully understand could also mix the gas to reproduce the same result,” adds co-author Jean-Loup Bertaux, Principal Investigator for the instrument on Venus Express that made the detections.

Venus has a “super-rotating” atmosphere that whips around the planet in just four Earth-days, much faster than the 243 days the planet takes to complete one rotation about its axis.







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