Until now, it's been thought that clouds on Mars don't move water in a way that allows snow to form but new mathematical models published in Nature Geoscience today suggest it is indeed possible for convection snowstorms to occur in the Martian atmosphere — at night.

Why it matters: Researching snow on Mars has been important to understanding water on the planet and the Martian climate. "There [are] a couple of holy grails in Mars science," Hanna Sizemore, an expert on ground ice on Mars at the Planetary Science Institute who wasn't involved in the research, told Axios. "One of them is life, biology, and one of them, which is linked to the first, is understanding the water cycle." The authors say their study shows snow precipitation may have "played a key role in forming tropical and mid-latitude glaciers on Mars."

Why it happens at night and not during the day: At night there's no sunlight shining on the clouds and the ice particles floating around, so they cool down. And when they cool down, they're denser and heavier, so they fall. During the day, they're a little stabler because "warm air is moving upward in convection, but the ice clouds are being warmed from above and no cooling can take place," Isaac Smith, who works with the U.S. SHARAD team, said. Since the clouds are neither cooling nor heating, the unstable layers that drive the snowstorms can't form.

"One of the reasons this wasn't understood earlier is because this is occurring at night. Our observational data is fairly limited to daytime observations," an expert on Mars' climate history , Nathaniel Putzig, said. "It's kind of hard to catch it in the act."

What's next: Nicholas Heavens from Hampton University suggested future research might try modeling different time periods on Mars to see if those different climate conditions persisted and could have resulted in snowfall to the surface to form glaciers. Ultimately, he notes the need for "more observations to firmly demonstrate that this is happening on Mars," not just a model.

Go deeper

Bryan Walsh, author of Future
3 hours ago - Science

The murder hornets are here

A braver man than me holds a speciment of the Asian giant hornet. Photo: Karen Ducey/Getty Images

Entomologists in Washington state on Thursday discovered the first Asian giant hornet nest in the U.S.

Why it matters: You may know this insect species by its nom de guerre: "the murder hornet." While the threat they pose to humans has been overstated, the invading hornets could decimate local honeybee populations if they establish themselves.

Biden is highest-spending political candidate on TV ads

Joe Biden. Photo: Sean Rayford/Getty Images

After spending an additional $45.2 million on political ads this week, former Vice President Joe Biden has become the highest-spending political candidate on TV ads ever, according to data from Advertising Analytics.

By the numbers: In total, the Biden campaign has spent $582.7 million on TV ads between 2019 and 2020, officially surpassing Michael Bloomberg's record spend of roughly $582 million. Biden's spend includes his primary and general election advertising.