Studies of the Red Planet tell us that Mars is covered by a thin atmosphere which consists mostly of carbon dioxide. So, the scientists at Caltech believe there had to be another process at work. If it were true, scientists wonder: where did all the carbon go? But measurements indicate that the Martian atmosphere has far more carbon-13 than carbon-12, but why? On the one hand, he says, the team looked at the atmospheric chemistry-the isotopic signature, the escape processes, and the enrichment mechanism. Some of the carbon atoms then had enough energy to escape the atmosphere – in this case, carbon-12 had more energy than carbon-13.
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This previously dense atmosphere that may have had a surface pressure similar to Earth’s, has evolved through time into a tenuous one.
Ehlmann said that the planet’s atmosphere must have been thick enough to prevent liquid water from evaporating, if the planet ever had some.
A new study found that Mars has been a desert wasteland since its very beginning, rather than a hospitable world with lush atmosphere as recent studies had suggested. For decades that left the question, “Where did all the carbon go?” The solar winds are still removing tons of carbon dioxide every day. They found that the atmosphere is unusually abundant in carbon-13.
They suggest that around 3.8 billion years ago Mars might have the atmosphere more or less same as the Earth and it gradually transitioned to its current state.
To study the escape-to-space scenario, scientists examine the ratio of carbon-12 and carbon-13, two stable isotopes of the element carbon that have the same number of protons in their nuclei but different numbers of neutrons, and thus different masses.
Indeed, California Institute of Technology (Caltech) postdoctoral fellow Renyu Hu, “Our paper shows that transitioning from a moderately dense atmosphere to the current thin one is entirely possible”. “It is exciting that what we know about the Martian atmosphere can now be pieced together into a consistent picture of its evolution – and this does not require a massive undetected carbon reservoir”.
Researchers said there were two plausible mechanisms that could explain the removal of excess carbon dioxide in the planet.
There are two possible scenarios that researchers consider for the missing carbon: Either the CO2 was incorporated into minerals in rocks called carbonates or it was lost to space. The findings were compared with data from MAVEN mission, which was especially designated to provide an answer to why Mars lost its atmosphere long time ago.
In order to establish a starting point, the researchers used measurements of the carbon isotope ratio in Martian meteorites that contain gases that originated deep in the planet’s mantle. The modern ratio comes from measurements by the SAM (Sample Analysis at Mars) instrument on NASA’s Curiosity rover.
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This process is known as “sputtering” where carbon dioxide in the atmosphere escapes to space, which is also linked to solar wind and upper atmosphere activities. As a result of it, Mars loses about 100 grams of particles from its atmosphere in every second. There are three types of carbon isotopes found naturally, which is 12, 13, and 14. The process is also incredibly consistent with carbon isotopic measurements that exist today.
