Heat and dust help launch Martian water into space, scientists find

This graph shows how the amount of water in the atmosphere of Mars varies depending on the season. The amount of water spikes during global and regional dust storms, which occur during the southern spring and summer. Credit: University of Arizona / Shane Stone / NASA Goddard / Dan Gallagher

Scientists using NASA’s Mars Atomosphere and a device in the volatile Evoltion, or MAVN, have detected from spacecraft that water vapor near the surface of the red planet evaporates to a higher level than anyone would expect. Was not. There, this electrically charged gas is easily destroyed by particles — or ions — and lost in space.

Researchers said the phenomenon they uncovered is one of several that have lost Mars the equivalent of a global ocean of water hundreds of feet (or hundreds of meters) over billions of years. Reporting on his discovery in the Journal on 13 November Science, Researchers said, that Mars continues to lose water even today as the vapor is carried to higher altitudes after separating from the frozen polar cap during warmer weather.

“We were all surprised to find water in the atmosphere,” said Shane W. Stone, a Lunner at the University of Arizona in Tucson and a doctoral student in planetary science at the Planetary Laboratory. “The measurements we use can only come from MAVEN because it is higher than the planet’s surface through the atmosphere of Mars.”

To make their discovery, Stone and his colleagues relied on data from MAVEN’s Neutral Gas and Ion Mass Spectrometer (NGIMS), which was developed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The mass spectrometer inhales air and separates the ions it contains by its mass, which is how scientists have identified them.

Stone and his team tracked the abundance of water ions on Mars for more than two Martian years. In doing so, they determined that the amount of water vapor, about 93 miles or 150 kilometers above the surface, is highest during the summer in the Southern Hemisphere above the surface. During this time, the planet is closest to the Sun, and thus warmer, and more likely to become dust storms.

Heat and dust help launch Martian water into space, scientists find

This illustration shows how water is generally lost on Mars versus during regional or global dust storms. Credit: NASA / Goddard / CI Lab / Adriana Manrique Gutierrez / Crisprofer Kim

Hot summer temperatures and strong winds associated with dust storms allow vapor to reach the upper reaches of the atmosphere, where it can easily be broken down into its constituents oxygen and hydrogen. Hydrogen and oxygen then escape into space. Previously, scientists thought that water vapor was trapped close to the Martian surface like it is on Earth.

“Everything that makes it to the higher part of the atmosphere is destroyed on Mars or on Earth,” Stone said, “because it is that part of the atmosphere that is exposed to the full power of the Sun.”

Researchers measured 20 times more water than two days in June 2018, when a severe global dust storm covered Mars (which put NASA’s Opportunity Rover out of commission). Stone and his colleagues estimated that Mars lost as much water in 45 days during this storm as it typically does throughout the Martian year, lasting several Earth years.

“, We have shown that dust storms disrupt the water cycle on Mars and push water molecules higher into the atmosphere, where chemical reactions can release their hydrogen atoms, which are then lost to space, “Said Paul Mahaffy, director of the Solar Systems Exploration Division at NASA Goddard and chief investigator of NGIMS.

Other scientists have also found that Martian dust storms can lift water vapor far above the surface. But no one has yet realized that water will carry it to the top of the atmosphere. There are abundant ions in this region of the atmosphere that can break down water molecules 10 times faster than they are destroyed at lower levels.

Mehdi Bena, Goddard’s planetary scientist and co-investigator of MAVN’s NGIMS instrument, said, “What is unique about this discovery is that it gives us a new path that we have taken to survive the Martian environment for water. I did not think. ” “This will fundamentally change our estimates of how fast water is escaping today and how fast it has survived in the past.”

Escape From Mars: How Water Flows From Red Planet

more information:
Shane W. Stone et al. Hydrogen migration from Mars is driven by seasonal and dust storm transport of water, Science (2020). DOI: 10.1126 / science.baba 5229

Provided by NASA’s Goddard Space Flight Center

Quotes: Heat and dust help launch Mars water into space, scientists discover (2020, November 13) from https://phys.org/news/2020-11-martian-space-scientists.html Retrieved 15 November 2020

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