On Earth, clouds usually form when water vapor creates droplets or ice crystals in the presence of small particles, such as dust or salt. The new study, published in Nature Geoscience, suggests instead that AMEC can be formed by so-called homogeneous nucleation, where steam turns directly into ice crystals alone without the help of debris.
“It’s similar to condensation drops that appear in the middle of a room, rather than on a window,” Hernández-Bernal explained. “It’s very unexpected.”
This phenomenon requires extreme conditions – a sharp temperature drop of 30 ° Celsius within 10 minutes and high relative humidity. The volcano Arsia Mons also plays a key role. When the wind current hits the 65,000-foot-high volcano, a powerful wave is created that launches moist air high in the atmosphere in a matter of minutes.
Scientists have assumed that a similar phenomenon could occur in the upper atmospheres of other planets, including Venus and even Earth, but it has never been observed. This is not too surprising given the extreme humidity required for this phenomenon, which is more than 100,000 times greater than any value measured on Earth.
Prior to this modeling, it was not known that these humidity levels also exist on Mars. “We don’t have nearly as much information about the atmosphere of Mars as we do about Earth, so reproducing the AMEC to this degree is a great success,” said Hernández-Bernal, adding, “the result is remarkable.”
This story originally appeared on WIRED Czech Republic and Slovakia and was translated from Czech.