For decades scientists have observed a series of catastrophic landslides called slope streaks on Mars. Viking orbiters first appeared in the 1970s, all orbiter machines have since seen them, but the machine behind the slope streaks has had a heated debate: could they be caused by water work on the Red Planet, or are they the result of some kind. dry mechanic?It turns out that the leading candidate is “dry.” But scientists with Mars Odyssey machines have confirmed another reason behind the slope lines: carbon dioxide.
Slope streaks usually appear on the walls of caves or on the sides of hills or mountains. Previous research has determined that Martian dust and rocks on slopes can be released as small as a passing dust dust, or even an impact event in the right place. These events create avalanches of dry dust on Mars. Some studies have suggested that the reduction of carbon dioxide frost can lead to rocks, causing avalanche, but now photos and data from the Odyssey spacecraft have found solid evidence.
The Odyssey has been in orbit since 2001, and is the longest-running Mars missile machine. The current spacecraft offers a unique view of the planet at 7 a.m. local time on Mars, which – like Earth – is the perfect time to look at the work of snow.
Last year, scientists were astounded to see blue and white light from the rising sun in photographs taken by a light camera visible on the Odyssey board. But Odyssey also has a Thermal Emission Imaging System (THEMIS), and this heat-sensitive camera showed that snow is highly visible, including in areas where the visible light camera is invisible. . The Odyssey Morning route produces beautiful images, ”said Sylvain Piqueux of NASA’s Jet Propulsion Laboratory in Southern California, who led the paper. “We can see the long shadows of the rising sun as they stretch out.”
According to NASA, because Mars has a very small atmosphere (only 1% of Earth’s crust), the Sun quickly burns the ice that fills the whole night. Instead of melting, dry ice evaporates in space within minutes.
Lucas Lange, a trainee at Jet Propulsion Laboratory working with Piqueux, first saw a cold temperature signature from THEMIS of snow in many places where it was not visible from above. These temperatures ranged from tens of thousands of microns below the surface of the earth – below the width of human hair “below”.
“We started with the idea that snow could be buried there,” Lange said in a statement. “There is a lot of dry snow near the poles of Mars, but we were looking at the planet’s equator, where it is usually very warm to have a dry frost.”In the same areas, sloping slopes or even greater landslides were observed. The team explains in their paper:
“At sunrise, the winds driven by sublimation within the regolith become strong enough to remove individual dust particles, launching and trapping dust avanches on steep slopes, creating subdivisions known as slope streaks. This model suggests that the CO2 ice cycle is a geomorphological agent that works at all latitudes not just at high or polar surface, and may be an important factor in keeping dust pools moving upwards.
The authors claim to have seen what they call “dirty snow” – dry snow mixed with fine dust particles hidden in visible light but not in infrared images. They suspect that polluted snow may indicate some of the black lines that stretch 3,300 feet (1,000 m) or more below the Martian slopes. They know that the trails are caused by, in fact, the glaciers that gradually change mountains around the world.
What if you were there to see such snow? Scientists say they think that these dust layers are almost like a river of dust flowing down the gutter. As the dust subsides every few hours, it exposes the rays of dark matter beneath it.”Every time we launch a campaign on Mars, we discover new and unique processes,” said Chris Edwards, a paper writer at Northern Arizona University in Flagstaff. “We don’t have anything exactly like the slope streak on Earth. You have to think beyond your experience on Earth to understand Mars. “
Source Journal Reference: L. Lange,S. Piqueux, and C. S. Edwards, Gardening of the Martian Regolith by Diurnal CO2 Frost and the Formation of Slope Streaks, JPR Planets, March (2022)https://doi.org/10.1029/2021JE006988
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