The Bay Space is in the midst of a frigid
chilly snap, pushed by a blast of icy Arctic air.
However winter temperatures on Mars can drop over 200 levels decrease. Amid these bitterly chilly situations, the Crimson Planet develops ice, frost and — at its coldest extremes — a number of toes of snow.
This isn’t water-based snow, like what’s piled up in California’s
Sierra Nevada. As a result of the Crimson Planet is so dry and so chilly, scientists don’t suppose that such snowflakes would make it right down to the floor.
However one other sort of snow, made up of carbon dioxide, does.
“Sufficient falls that you could possibly snowshoe throughout it,” stated Sylvain Piqueux, a Mars scientist at NASA’s Jet Propulsion Laboratory.
There are just a few the reason why this dry-ice snow falls from Martian skies. For one, the Crimson Planet has a definite winter season — not the case for all planets. The planet spins round a tilted axis and, like Earth, the northern and southern hemispheres expertise pronounced seasons over the course of 1 lap across the solar.
This lap is about twice so long as one Earth 12 months as a result of Mars is farther away from the solar than we’re. That implies that not solely does Mars obtain much less heat from the solar, it has winters which can be about twice as lengthy.
“Issues are actually, actually chilly,” Piqueux stated.
Throughout frigid Martian winters, patches of carbon dioxide frost (blue, on this enhanced-color picture) can kind on the floor, like on this Southern Hemisphere crater.
NASA / JPL-Caltech / College of ArizonaThese frigid temperatures trigger carbon dioxide and water frost to kind on the floor of the Crimson Planet, particularly on the poles, the place the chilliest situations happen. That’s the place scientists suppose that as much as a number of toes of dry-ice snow falls throughout Martian winters.
Reasonably than trying like Earth’s six-sided snowflakes, Martian snowflakes would have a completely alien look.
“They’re most likely trying like little cubes,” Piqueux defined.
This distinction is because of how carbon dioxide molecules pack themselves when frozen. The snowflakes would even be tiny — smaller than the width of a human hair.
Scientists know a lot about frost and snow on Mars due to detailed measurements by satellites circling the planet, which use particular devices to see down onto the floor.
The Martian floor develops a skinny layer of water frost in the course of the winter, as captured by Viking 2 on Might 18, 1979.
NASA / JPLSpacecraft, just like the Viking lander, have additionally made it to the bottom and supplied a close-up view of frost on the Martian floor.
“These had been extremely lovely pictures,” Piqueux stated.
New Yr’s on Mars kicked off Dec. 26, 2022. Since a Martian 12 months is 687 Earth days, the date shifts round our present Gregorian calendar. This additionally marks the beginning of spring, when ice that constructed up in the course of the winter begins to thaw. However reasonably than turning to liquid, dry-ice frost and snow go straight to forming a fuel — a course of generally known as sublimation.
When the solar shines by means of translucent ice, layers nearer to the floor can disappear first, inflicting pockets of fuel to kind. When sufficient stress builds up, this carbon dioxide tears free.
“You begin creating geysers,” Piqueux stated.
When carbon dioxide fuel escapes by means of ice on the Martian floor, it will probably launch followers of darker materials (blue, on this enhanced-color picture). Right here, water ice additionally cut up the bottom into polygons.
NASA / JPL-Caltech / College of Arizona
As Martian ice thaws, the floor may tackle distinctive fracture patterns, like weirdly formed polygons and
spiders.
“You don’t have anything prefer it on Earth,” Piqueux stated.
Jack Lee (he/him) is a San Francisco Chronicle workers author. Electronic mail: [email protected]