Magnesium from passing comets could be a key part of the Red Planet’s cloud-starter kit
JPL-NASA, Cornell Univ.
The seeds for Martian clouds may come from the dusty tails of comets.
Charged particles, or ions, of magnesium from the cosmic dust can trigger the formation of tiny ice crystals that help form clouds, a new analysis of Mars’ atmosphere suggests.
For more than a decade, rovers and orbiters have captured images of Martian skies with wispy clouds made of carbon dioxide ice. But “it hasn’t been easy to explain where they come from,” says chemist John Plane of the University of Leeds in England. The cloud-bearing layer of the atmosphere is between –120° and –140° Celsius — too warm for carbon dioxide clouds to form on their own, which can happen at about –220° C.