Evidence suggests volcanoes could be active on Venus

A radar image taken by the Magellan spacecraft in 1996, shows lava flows and pools on the surface of Venus. (The New York Times/NASA/JPL)
A radar image taken by the Magellan spacecraft in 1996, shows lava flows and pools on the surface of Venus. (The New York Times/NASA/JPL)

Venus is our toxic twin. Its chemical makeup, size and density are similar to our world's, although its hellish temperatures can melt lead, and its atmosphere is rife with sulfuric acid.

But it may be even more Earthlike than we knew. A paper published Jan. 3 in Science Advances demonstrates that Venus might still harbor active volcanoes. If confirmed, the finding could help astronomers and planetary scientists as they search for life on other worlds.

Scientists have long debated whether Venus might be volcanically active. In the early 1990s, cloud-penetrating radar on the Magellan orbiter revealed a surface studded with volcano-like mountains. But no one knew whether these features remained active. Then in 2010, data from Europe's Venus Express spacecraft revealed several hot spots that suggested lava had flowed as recently as 250,000 years ago. And in 2012, the orbiter observed spikes in sulfur dioxide — a gas that smells like a struck match and is commonly produced on Earth by active volcanoes — within the Venusian atmosphere.

The evidence was tantalizing but incomplete. "The data that are currently available for Venus cannot unequivocally provide the smoking gun," said Tracy Gregg, a geologist at the University at Buffalo.

So Justin Filiberto, a planetary scientist at the Lunar and Planetary Institute in Houston, decided to take another look. His team experimented with crystals of olivine, a green mineral commonly found in volcanic rock. Specifically, they wanted to see how the mineral might change once it erupted into the hot, Venusian atmosphere.

To find out, the researchers heated olivine up to roughly 1,600 degrees Fahrenheit and exposed it to oxygen, which can also be found on Venus. Under such extreme conditions, the outer grains of olivine transformed into iron oxide, and very rapidly. Because olivine disappears quickly, the discovery of evidence of the mineral on the surface of Venus would signify young lava flows.

So Filiberto and his colleagues turned toward archived data from the Venus Express orbiter. They found that the lava flows previously dated at 250,000 years old actually contained olivine — proof that they were only a few years old.

"It means that Venus is a lot more like Earth than we thought," Filiberto said.

Style on 02/17/2020

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