Scientists have long known that Venus is full of volcanoes, but it is unknown whether these are active or not. The probe Venus Express of the European Space Agency (ESA) can help solve the mystery. The ship has seen great changes in the sulfur dioxide content of the atmosphere of the “morning star” and an intriguing possible explanation is volcanic eruptions.
The dense atmosphere of Venus contains more than a million times more sulfur dioxide than Earth, where most of this gas is pungent and toxic volcanic activity generated. Most of the sulfur dioxide in Venus hidden under the top cover of dense clouds of the planet, because the gas is easily destroyed by sunlight. That means that any detected sulfur dioxide in the upper atmosphere of Venus above the cloud cover must have been recently driven from below.
The Venus Express had already found evidence to suggest volcanism in geologically recent time scales in the past hundreds of thousands to millions of years. A previous analysis of the infrared radiation from the surface lava flows indicated at the top of a volcano with a composition different from that of their environment, suggesting that the volcano had erupted in the recent past of the planet. now, the analysis of the sulfur dioxide concentration in the upper atmosphere for six years provides a new track.
Immediately after arriving at Venus in 2006, the spacecraft recorded a significant increase in the mean density of sulfur dioxide in the upper atmosphere, followed by a sharp decrease of approximately ten times lower values. A similar drop was also observed during the mission for NASA Pioneer Venus orbiting the planet since 1978 to 1992.
At that moment, the explanation was preferred before injection of sulfur dioxide from one or more volcanoes, Pioneer Venus arriving in time to record the descent. “If there is an increase of sulfur dioxide in the upper atmosphere, is known to have been produced by a recent, because that individual molecules are destroyed by sunlight after a couple of days,” says Emmanuel Marcq, the Laboratory Atmospheres, Environments and Observations Spatiales (France), and author of the paper published in the journal Nature Geoscience.
Several active volcanoes
“A volcanic eruption could act as a piston to the explosion of sulfur dioxide at these levels, but the peculiarities of the circulation of the planet who still do not fully understand also could mix the gas to reproduce the same result,” adds co-author Jean- Loup Bertaux, principal investigator of Venus Express, which made the detections.
Venus has an atmosphere in “super-rotation” plaguing the entire planet in just four Earth days, much faster than the 243 days it takes the planet to complete one revolution around its axis. Such air circulation sulfur dioxide spreads around, so that it is difficult to isolate any of the individual points of the gas source . Marcq equipment if volcanism speculated that was responsible for the initial increase, then it could come from an increase in the production of relatively soft active volcanoes erupt rather than spectacular.