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Mars may seem like a dry and 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 emptied into Jezero Crater billions of years ago.
As the main feature of the planet, dust also determines the Martian climate. Dust often heralds the arrival of winter, but the planet is no stranger to snow, ice, and frost. At the Martian poles, the temperature can drop as low as minus 190 degrees Fahrenheit (minus 123 degrees Celsius).
There are two types of snow on Mars. One is the kind we experience on Earth, made of frozen water. Thin Martian air and freezing temperatures mean that traditional snow sublimates, or goes directly from a solid to a gas, before hitting the ground on Mars.
The other type of Martian snow is carbon dioxide or dry ice based, and can land on the surface. A few feet of snow tends to fall on Mars in its flat regions near the poles.
“Enough drops to snowshoe through,” said Sylvain Piqueux, a Mars scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, in a NASA statement. “However, if you were looking to ski, you would have to go into a crater or a cliff, where snow could accumulate on a sloping surface.”
So far, no orbiter or rovers have been able to see snow falls on the red planet because the weather phenomenon only occurs at the poles below cloud cover at night. Orbiter cameras cannot see through clouds, and robotic rovers have not been developed that can survive the frigid temperatures at the poles.
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However, the Mars Reconnaissance Orbiter’s Mars Climate Sounder instrument can detect light that is invisible to the human eye. He has made detections of carbon dioxide snow falling at the Martian poles. The Phoenix lander, which arrived on Mars in 2008, it also used one of its laser instruments to detect frozen snow from its location about 1,000 miles (1,609 kilometers) 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 bit different.
“Because carbon dioxide ice has a symmetry of four, 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 Mars orbit in 2001) watched frost form and turn to gas in sunlight, while the Viking landers detected icy frost on Mars when they arrived in the 1970s.
At the end of winter, the season’s ice buildup can thaw and turn to gas, creating unique shapes that have reminded NASA scientists of Swiss cheese, Dalmatian spots, fried eggs, spiders and other unusual formations.
During the winter in Jezero Crater, recent high temperatures have been about 8 F (minus 13 C), while lows have been minus 120 F (minus 84 C).
In the meantime, In Gale Crater in the southern hemisphere near the Martian equator, the Curiosity rover, which landed on Mars in 2012, has been experiencing highs of 5 F (minus 15 C) and lows of minus 105 F (minus 76 C).
Seasons on Mars tend to be longer because the planet’s oval-shaped orbit around the sun means that a single Martian year is 687 days long, or almost two Earth years.
NASA scientists celebrated the new year of Mars on December 26, which coincided with the arrival of the vernal equinox in the northern hemisphere.
“Scientists count Martian years from the planet’s northern spring equinox which occurred in 1955, an arbitrary point to start, but it helps to have a system,” according to a post on NASA’s 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 decades.”
Source: news.google.com