A joint effort between the European Space Agency and NASA has resulted in further evidence for the appearance of geologically recent eruptions on Venus. The NASA run Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on ESA’s Venus Express spacecraft measured the brightness of the surface in infrared light. What it found when comparing the results to radar maps carried out by NASA’s Magellan spacecraft in the 1990-1994 period was a region of the Venusian surface comparable to the volcanic region of Hawaii had a different brightness than the surrounding region. This suggests a different composition, itself suggesting that weathering processes haven’t had time to convert the new rock into something that looks like the old rock from above.
The VIRTIS team believe that this puts the time at which the volcano last erupted at between a few hundred to 2.5 million years ago (recent in a geological sense). Evidence previously gathered includes gravitational sensing by Magellan that suggested plumes of material rising under the surface of Venus. The atmosphere also contains a number of volcanic gases that are slowly breaking down and the VIRTIS team also identified a few minerals associated with volcanic flows. The surface of Venus contains only a thousand or so impact craters, suggesting something has been wiping the surface clean, most likely, it seems from this result, a stream of gradually erupting volcanoes.