Water leaks Mars’s atmosphere through fluctuating seasons and swirling Martian storms, scientists found in two new studies.
There is water on Mars, but it seems to exist only in ice sheets at the poles of the planet or in the thin atmosphere of the planet. Water has been escaping the planet for billions of years since Mars lost its magnetic field (and beyond) lots of its air and water), and two new studies show how water moves and leaves the planet’s atmosphere.
The two new studies, led by Anna Fedorova, a researcher at the Space Research Institute of the Russian Academy of Sciences, and Jean-Yves Chaufray, a scientist at the Laboratory Atmospheres Observations Spatiales in France, use data from the European Space Agency (ESA). ExoMars orbit, which began in 2018 with its main scientific mission, and ESA’s Mars Express orbit, to show that the escape rate of Martian water is determined by changing weather and climate on Mars and the distance of the planet from the sun.
“The atmosphere is the link between surface and space, so we have to tell a lot about how Mars lost its water,” Fedorova said. said in an ESA statement.
Related: Mars may be wetter than we thought (but still not as habitable)
In these studies, the teams used data from ExoMars’ SPICAM (Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars) instrument, which observed the atmosphere of Mars.
“We studied the water vapor in the atmosphere from the ground up to [62 miles] 100 kilometers in altitude, an area yet to be explored, over eight Mars years, “Fedorova said. (One year on Mars is about two years on Earth.)
The researchers found that water vapor in Mars’ atmosphere is really just less than 60 km from the planet’s surface, if the planet is furthest from the sun, about 400 million kilometers (400 million km) away. However, if the planet is closest to the sun, about 333 million kilometers, water can be found up to as far as 90 kilometers above the surface.
When Mars and the sun are further apart, the cold causes the water vapor to freeze at a certain height in the atmosphere of Mars, but as the planet gets closer and warmer, the water can circulate further. Because water vapor can travel further into the atmosphere of Mars during warmer seasons, these are also the times when the planet loses more water.
“The upper atmosphere is moisturized and saturated with water, which explains why the escape of water during this season is accelerating – water is carried higher, which helps the escape to space,” Fedorova said.
But it’s not just seasons that determine how much of Mars’ water leaks into space; dust storms also play an important role, the researchers found in these studies. In scientists from more than eight years of data, the scientists found that water traveled higher in the planet’s atmosphere during the years in which Mars experienced global dust storms. In those years, researchers found water vapor more than 80 km from the planet’s surface.
Scientists have found that Mars loses the equivalent of a global planet every billion years [six feet] two meters deep layer of water, ”according to the statement.
“This confirms that dust storms, which are known to heat the atmosphere of Mars, are also delivering water to great heights,” Fedorova said. “Thanks to the continuous monitoring of Mars Express, we were able to analyze the last two global dust storms, in 2007 and 2018, and compare what we found with storm-free years to determine how the storms affected the escape of water from Mars.”
Yet this work does not explain the amount of water Mars has lost over the past 4 billion years, according to the statement. “There must have once been a significant amount on the planet to explain the water-created features we see,” Chaufray said. “Since not all of it was lost in space, our results suggest that the water moved underground, or that escape rates were much higher in the past.”
These two studies were December 11, 2020 published in the Journal of Geophysical Research: Planets and January 1 in the journal Icarus.
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