NASA scientist confirms Mars volcano isn't smokin' hot

And it hasn't been for about 50 million years. There's a big difference between a smoke plume and a cloud.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
2 min read

This Mars image from Sept. 24 shows the cloud near the Arsia Mons volcano.

ESA/Red arrow by Amanda Kooser/CNET

You may have noticed some consternation in some corners of the internet about a possible volcanic eruption on Mars. As it turns out, things are still pretty chill on the red planet and it's not getting all Vesuvius on us. 

The European Space Agency's Mars webcam on board its Mars Express orbiter shared some nifty images in late September. What's notable here is a large volcano named Arsia Mons and a streak-like formation that appears to emanate from it. 

Some viewers saw that long formation above the planet's surface and assumed it meant an eruption was happening. But the streak is not a smoke plume caused by an eruption. It's a cloud. 

Italian debunking site ufooffinterest.org pointed out on Twitter some previous examples of long, thin clouds forming near Arsia Mons.

Planetary scientist Tanya Harrison is a member of NASA's Opportunity rover team and specializes in Mars geology and weather. She also took to Twitter to quash the Mars eruption talk. 

"It's not a plume of smoke, but rather water ice clouds condensing out over the summit of the Arsia Mons volcano. We see them quite often over this particular volcano," Harrison writes. 

While some Twitter commentators accused NASA of hiding evidence of a volcanic eruption, Harrison shared an image from the space agency's Mars Reconnaissance Orbiter showing clouds above Arsia Mons earlier in October. 

"We see these clouds hang out over the summit of Arsia for weeks at a time during this time of year, every year," Harrison writes. She says the volcano's high elevation combined with water vapor in the atmosphere causes the clouds to form.

Mars once had a robust volcanic past, but NASA research shows Arsia Mons was last active around 50 million years ago, about the time when dinosaurs went extinct on Earth. 

You can bet NASA and ESA would be trumpeting the news if either space agency witnessed a fresh volcanic eruption on the red planet. 

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