Last April, NASA's Mars Insight Lander sent a photo from Mars, and it featured the sunset on the Red Planet in a very overcast condition. Clouds can be seen hovering in the skies of Mars, but interestingly, no rains were observed. Why does it happen? Why there are no rains on Mars despite thick clouds in the skies?
In earth, clouds are made of water vapor, and it eventually rains as water to the planet's surface. However, in Mars, things are entirely different. Even though there is more water vapor in Mars compared to earth, Martian clouds are made up of water ice, like the thin ice fog and haze that result in very cold days without any precipitation.
The Red Planet's very thin atmosphere and bitter cold temperatures keep these frozen clouds away from ever falling to the surface as rain or snow, and this is the major reason behind the absence of rain on Mars. However, NASA reveals that there is a different kind of precipitation on the Red Planet and that is in the form of frost.
"This precipitation most likely takes the form of frost, rather than rain or snow. The ground is likely to be colder than the air (especially on cold clear nights), and so air hitting the ground cools and the water freezes to the ground as frost," says NASA.
NASA also made it clear that Viking II, a Mars lander in the 1970s had seen frost on the ground some mornings. It should be also noted that only a part of the polar ice caps of Mars is made of precipitated water ice and the remaining regions are made of carbon dioxide as dry ice.
A few days back, NASA had revealed that they have detected the first seismic tremor on Mars. Interestingly, this development is widely considered a giant leap, and it was for the first time that a human probe detected seismic activities on the Red Planet.