NASA images show the eerie beauty of winter on Mars
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Mars may seem like a dry, desolate place, but the red planet turns into an alien wonderland in the winter, according to an new video shared by NASA.
It is late winter in the northern hemisphere of Mars, where the Perseverance rover and Ingenuity helicopter explore an ancient river delta that once flowed into the Jezero crater billions of years ago.
As the main feature of the planet, dust also drives the weather on Mars. Dust usually heralds the arrival of winter, but the planet is no stranger to snow, ice and frost. At the poles of Mars, temperatures can drop to 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. The thin air on Mars and sub-zero temperatures mean that traditional snow sublimates, or transitions directly from a solid to a gas, before hitting the ground on Mars.
The other type of Martian snow is based on carbon dioxide or dry ice and can settle on the surface. A few feet of snow usually falls on Mars in its flat regions near the poles.
“There’s enough fall to walk on in snowshoes,” Sylvain Piqueux, a Mars scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., said in a statement from a media outlet. NASA release. “However, if you were looking to ski, you would have to go into a crater or cliff, where snow can accumulate on a sloped surface.”
So far, no orbiters or rovers have succeeded to see snow falls on the red planet because the weather phenomenon only occurs at night at the poles under cloud cover. The cameras on the orbiters can’t peer through the clouds, and no robotic explorers have been developed that could survive the freezing temperatures at the poles.
However, the Mars Climate Sounder instrument on the Mars Reconnaissance Orbiter can detect light invisible to the human eye. It has made detections of carbon dioxide snow falling on Mars’ poles. The phoenix lander, who arrived on Mars in 2008, also used one of its laser instruments to detect water-ice snow from its site about 1,000 miles (1,609 km) from Mars’ north pole.
Thanks to photographers, we know that snowflakes on Earth are unique and hexagonal. Under a microscope, Martian snowflakes would probably look a little different.
“Because carbon dioxide ice has a symmetry of four, we know that dry ice snowflakes are cubic,” Piqueux said. “Thanks to the Mars Climate Sounder, we can see that these snowflakes are smaller than the width of a human hair.”
Ice and carbon dioxide-based ices also form on Mars, and they may occur further away from the poles. The Odyssey orbiter (which entered Mars’ orbit in 2001) has seen ice build up and turn into a gas in sunlight, while the Viking landers saw icy frost on Mars when they arrived in the 1970s.
At the end of winter, the season’s ice buildup can thaw and turn into gas, creating unique shapes that remind NASA scientists of Swiss cheese, Dalmatian spots, fried eggs, spiders and other unusual formations.
During winter in the Jezero craterrecent highs have been around 8°F (minus 13°C), while lows have been around minus 120°F (minus 84°C).
In the meantime, Bee Gale crater in the southern hemisphere near the equator of Mars, the rover Curiosity, which landed on Mars in 2012, has recorded 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 lasts 687 days, or nearly 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 are counting Martian years from the planet’s northern vernal equinox which occurred in 1955 — an arbitrary starting point, but it’s helpful to have a system,” said a post on the NASA Mars Facebook page. “Numbering Martian years helps scientists track long-term observations, such as weather data collected by NASA spacecraft over the past several decades.”
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