WASHINGTON: A team of scientists has offered an explanation of the “missing” carbon on Red Planet, suggesting that it may have escaped into the atmosphere owing to the strong ultraviolet (UV) rays from the Sun.
They suggest that 3.8 billion years ago, Mars might have had a moderately dense atmosphere.
Such an atmosphere — with a surface pressure equal to or less than that found on Earth — could have evolved into the current thin one.
“Our paper shows that transitioning from a moderately dense atmosphere to the current thin one is entirely possible,” says postdoctoral fellow Renyu Hu from California Institute of Technology (Caltech).
The solar wind stripped away much of Mars’ ancient atmosphere and is still removing tons of it every day.
There are two possible mechanisms for the removal of the excess carbon dioxide.
Either the carbon dioxide was incorporated into minerals in rocks called carbonates or it was lost to space.
One way carbon dioxide escapes to space from Mars’ atmosphere is called sputtering, which involves interactions between the solar wind and the upper atmosphere.
NASA’s MAVEN (Mars Atmosphere and Volatile Evolution) mission has yielded recent results indicating that about about 100 grams of particles every second are stripped from today’s Martian atmosphere via this process.
Sputtering slightly favours loss of carbon-12, compared to carbon-13, but this effect is small.
