Simulations point to homogeneous nucleation in a cloud over Mars — Live Science
New computer simulations have indicated a possible mechanism behind the formation of the elongated Arsia cloud, or AMEC, which appears almost daily above the Arsia volcano on Mars and can reach 1,800...
New computer simulations have indicated a possible mechanism behind the formation of the elongated Arsia cloud, or AMEC, which appears almost daily above the Arsia volcano on Mars and can reach 1,800 kilometers in length. Researchers suggest that homogeneous nucleation plays a key role — the formation of ice particles from water vapor without the involvement of dust or other particles in the atmosphere, Live Science reports .
The cloud appears in the morning AMEC forms near the extinct Arsia volcano, about 20 kilometers high, in the Tharsis region south of the Martian equator. It was first recorded by the European Space Agency's Mars Express orbiter in 2018. Since then, the cloud has been observed almost every morning during the Martian spring and summer, when stronger solar radiation causes powerful near-surface winds.
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The cloud forms when summer winds lift water vapor up the volcano's slopes. It exists for only a few hours before completely evaporating. Researchers classify AMEC as an orographic cloud, which forms as a result of air moving over elevated terrain.
More current news is available on the UA.News Telegram channel Telegram . A mechanism without dust particles On Earth, clouds usually form through heterogeneous nucleation: cooled moist air condenses into ice crystals around tiny particles of dust, salt, pollen, or soot. Although dust is present in the Martian atmosphere, modeling of AMEC pointed to a different process — the direct transformation of water vapor into ice particles.
According to the authors' calculations, air rising along Arsia's slopes creates a powerful wave and rapidly reaches the upper atmosphere. Its temperature can drop by 30 degrees Celsius in just 10 minutes. This increases humidity within the wave and creates conditions for homogeneous nucleation.
Some of the water, researchers believe, may come from a thick layer of frost at the volcano's summit. The study, published in the journal Nature Geoscience, is based on data from three Mars Express instruments: the Visual Monitoring Camera, the High Resolution Stereo Camera, and OMEGA.
The spacecraft is one of the few Mars probes capable of observing the Arsia volcano in daylight.
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