NASA images show strange beauty of winter on Mars

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ATLANTA — Mars may seem like a dry, desolate place, but the red planet transforms into an otherworldly wonderland in winter, according to a new video shared by NASA.

It’s late winter in the northern hemisphere of Mars, where the Perseverance rover and Ingenuity helicopter are exploring an ancient river delta that once fed into Jezero Crater billions of years ago.

As a major feature of the planet, dust also drives the Martian climate. Dust usually heralds the arrival of winter, but the planet is no stranger to snow, ice and frost. At the Martian poles, the temperature can drop to minus 190 degrees Fahrenheit.

There are two types of snow on Mars. One is what we experience on Earth, made of frozen water. The thin Martian air and subzero temperatures cause traditional snow to sublimate, or change from a solid directly to a gas, before it hits the ground on Mars.

The other type of Martian snow is carbon dioxide-based, or dry ice, and can land on the surface. A few meters of snow tend to fall on Mars in its flat regions near the poles.

“There are enough falls to snowshoe,” Sylvain Piqueux, a Mars scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement. Release from NASA. “If you’re looking to ski, though, you’d have to go to a crater or a cliff, where snow could build up on a sloping surface.”

So far, no orbiters or rovers have been able to see snowfall on the Red Planet because the weather phenomenon only occurs at the poles under cloud cover at night. Cameras on orbiters cannot see through clouds, and no robotic explorers have been developed that can survive freezing temperatures at the poles.

However, the Mars Climate Sounder instrument on the Mars Reconnaissance Orbiter can detect light invisible to the human eye. He has made detections of carbon dioxide snow falling at the Martian poles. The Phoenix Lander, that arrived on Mars in 2008, also used one of its laser instruments to detect water ice snow from its location about 1,000 kilometers away from the Martian north pole.

Thanks to photographers, we know that snowflakes on Earth are unique and six-sided. Under a microscope, Martian snowflakes would probably look a little different.

“Because carbon dioxide ice has fourfold symmetry, we know that dry ice snowflakes would be cube-shaped,” Piqueux said. “Thanks to the Mars Climate Sounder, we can tell that these snowflakes would be smaller than the width of a human hair.”

Frosts based on ice and carbon dioxide also form on Mars, and can occur farther from the poles. The Odyssey orbiter (which entered the orbit of Mars in 2001) has seen ice form and turn into a gas in sunlight, while the Viking landers saw icy frosts on Mars when they reach the seventies.

At the end of winter, the season’s ice buildup can thaw and turn into gas, creating unique shapes that have reminded NASA scientists of Swiss cheese, Dalmatian spots, fried eggs, spiders and other unusual formations.

during winter in the Jezero craterrecent highs have been around 8F, while lows have been around minus 120F.

Meanwhile, at Gale Crater in the Southern Hemisphere near the Martian equator, the Curiosity rover, which landed on Mars in 2012, has experienced highs of 5F and lows of minus 105F.

Seasons on Mars tend to last longer because the planet’s oval orbit around the sun means that a single Martian year is 687 days, or almost two Earth years.

NASA scientists celebrated the Martian New Year on December 26, which coincided with the arrival of the spring equinox in the Northern Hemisphere.

“Scientists count the years of Mars from the planet’s northern vernal equinox that occurred in 1955, an arbitrary point to start with, but it’s useful to have a system,” according to a publication in NASA Mars Facebook page. “Numbering the years of Mars helps scientists keep track of long-term observations, such as weather data collected by NASA spacecraft over the decades.”

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