Why the Discovery of an Active Volcano on Venus Matters

Venus had a lot going for it. Roughly the same diameter and density as Earth, it orbits in the solar system’s habitable zone—just the right distance from the sun for liquid water to exist. But the planet’s biological prospects were long ago wrecked by a runaway greenhouse effect that left it with an atmosphere that is 95% carbon dioxide, and 90 times the pressure of Earth’s—the equivalent of being a mile deep in the ocean. Venus’s surface temperatures hover at about 475º C (900º F), or hot enough to melt lead.

But there is one fiery feature of Earth that Venus has long been thought to lack: volcanoes. Without the plate tectonics that drive eruptions on Earth, Venus has been said to be a volcanically quiescent place, having seen its last blast perhaps a billion years ago. Or so it seemed. Now, however, a new paper in Science reveals modern-day volcanic activity on Venus—a discovery that may cause scientists to reconsider how rocky planets like Earth form and even help us look for habitable worlds surrounding other stars.
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The new findings rely on a fresh look at images captured of Venus by NASA’s Magellan spacecraft, which orbited the planet taking radar soundings of its surface from 1990 to 1994. Overall, Magellan mapped more than 40% of Venus’s face—capturing images that at the time, were stored on DVDs, and shipped to various astronomy labs in cardboard boxes. Now the Magellan images are available to researchers online. Robert Herrick, planetary scientist at the University of Alaska, Fairbanks, and Scott Hensley, senior research scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., took advantage of that fact to give the 30-year-old images a second look.

The area that attracted their attention is a region known as Alta Regio, …read more

Source:: Time – Science