Unusual clouds are formed each year on the Martian volcano Arsia Mons
ESA / DLR / FU BERLIN / J. COWART CC by-T 3.0 IO
A thin cloud that appears on Mars each year has disconcerted astronomers since its first identity, but it can be the result of an atmosphere rich in humidity which was deemed impossible.
Each winter, a 600 -kilometer cloud is formed near the Arsia Mons volcano in the south of the planet, appearing and disappearing every day for almost three months. The conditions of the atmosphere of Mars are clearly different from those of the earth, such as containing many small particles of dust which can trigger a water vapor in the air to condense in cloud particles. This produces many models of clouds that we do not see on earth, but the simulations which include these high levels of dust in Martian atmospheres cannot still form the distinctive characteristics of the Arsia Mons cloud.
Now, Jorge Hernández-Bernal at the University of Sorbonne in France and his colleagues say that they can reproduce the characteristics of the cloud if there is an extremely high quantity of water vapor in the air, something that was previously impossible in the atmosphere of March because of the high levels of dust. These high levels of water vapor help the particles of the clouds to form by an alternative and without dust route called homogeneous nucleation.
When the researchers directed simulations of the atmosphere around Mons Arsia with much higher water levels in the air, the resulting cloud seemed surprisingly similar to the real cloud, with a long tail moving away from the volcano which then spreads to form what is known as an explosion.
“The homogeneous nucleation requires, in the case of March, a much higher level of [water] saturation. This is why, in principle, we thought it was not possible on Mars, or was very improbable, “Hernández-Bernal told Europlanet Science Congress (EPSC) in Helsinki, Finland, September 10.” But in the last decade, we have learned that there is supersaturation on March. “
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