The measurements have fueled an old discussion: for some time now, some planetary scientists have argued that the high sulfur dioxide levels are an indication of active volcanism. Others believe that the responsible volcanic eruptions were already ten million years ago. Because sulfur dioxide can last up to twenty million years in the Venus atmosphere before it is destroyed by chemical reactions with the crustal rock. In the earth's atmosphere, another chemistry rules, where the gas disappears from the air within a few years.
Jean-Loup Bertaux is therefore skeptical whether the values are really an indication of currently active volcanoes. "But we can not explain the fluctuations, " he admits. He and his colleagues now want to look for more clues. For example, if high levels of sulfur dioxide are concentrated in an area of the planet, it may indicate the eruption cloud of an outbreak. An instrument of Venus Express that measures heat radiation could also record the heat of freshly emitted lava. Pierre Drossart of the Observatoire de Paris, who evaluates the heat measurements, reports: "So far, however, no heat anomaly has been found."Message from the ESA Ute Kehse advertisement