Our neighboring planet Venus is covered in volcanoes, but it's unclear whether they're still active. According to new research, there may, in fact, be signs of explosive activity on the planet.
The new study, published earlier this month in Geophysical Research Letters, is based on data from the European Space Agency's Venus Express spacecraft, which completed an eight-year study of the planet last year. That same spacecraft has given scientists other evidence of recent -- if not currently active -- volcanoes.
In 2010, scientists found that three volcanic regions on the planet seemed to have different compositions than the areas around them, suggesting that there was recently-spewed lava there. But they could only narrow that time window down to about 2.5 million years, so there was no way of knowing that volcanoes were still spouting lava.
In 2012, another study using data from the spacecraft reported a spike in sulfur dioxide in the planet's thick upper atmosphere, something that could have been caused by a major eruption.
But it turns out that Venus may have tell-tale hot spots on its surface.
“We have now seen several events where a spot on the surface suddenly gets much hotter, and then cools down again,” lead author Eugene Shalygin, from the Max Planck Institute for Solar System Research, said in a statement. “These four ‘hotspots’ are located in what are known from radar imagery to be tectonic rift zones, but this is the first time we have detected that they are hot and changing in temperature from day to day. It is the most tantalizing evidence yet for active volcanism."
Because of Venus's thick cloud cover, these kinds of infrared observations of the surface were at the very limit of the Venus Express's capabilities, the authors report.
According to the study, one of the hot spots -- called Object A -- is probably about half a mile square and shows a temperature of 1526 degrees Fahrenheit compared with a global average of 896.
“Our study shows that Venus, our nearest neighbor, is still active and changing in the present day," Håkan Svedhem, ESA’s Venus Express project scientist, said in a statement. "It is an important step in our quest to understand the different evolutionary histories of Earth and Venus.”