A cloudy sky could have let water flow through Mars long
Although today the Red Planet is a cold desert, it was home to relatively long-lived lakes and river systems about four billion years ago, as observed by NASA. Curiosity rover and other robots of Mars have shown.
Atmosphere of Mars then it was much thicker, which helped to prevent the boil-off of liquid surface water. However, it remains unclear how this water could have been liquid at all; in the sun was about 30% dimmer in that ancient era than today, so the surface of Mars, it would seem, was supposed to be a permanent winter wonderland.
Water on Mars: Research and Evidence
New research could help solve this mystery. A thin layer of icy clouds high in Martian atmosphere The researchers found that they could cause the greenhouse effect, warming the planet for a long time.
“There has been an unfortunate gap between our evidence and our ability to explain it in terms of physics and chemistry,” says lead author Edwin Keith, a planetary scientist at the University of Chicago. said in a statement… “This hypothesis is essential for bridging this gap.”
This cloud idea was the first proposed almost ten years ago but fell out of favor because “it was argued that it would only work if the clouds were implausible,” said Kite. For example, previous modeling work assumed that water had to exist in the Martian atmosphere for unrealistically long periods for the clouds to do their job of warming.
However, new work by Kaite and his modeling colleagues shows that thin but warming clouds could indeed have formed high above the planet, holding enough heat to keep liquid water on the surface – but only when certain conditions are met.
For example, the surface of Mars should have been covered with ice only partially, probably on the tops of the mountains and near the poles of the planet. Larger ice sheets would encourage low-altitude clouds to form, which do not retain heat very well and may even be negative because they reflect enough sunlight to cool Mars even further, the researchers said.
The team’s work confirms that Mars is an alien world with its own special processes and properties.
“In the model, these clouds behave very differently from Earth,” said Kite. “Building models based on earthly intuition just won’t work because it’s not at all like the Earth’s water cycle, which quickly moves water between the atmosphere and the surface.”
However, new research could help us better understand our own planet, as well as the history and evolution of inhabited worlds in general, he added.
“Mars is important because it is the only planet we know of that had the ability to support life – and then lost it,” said Kite. “The long-term climatic stability of the Earth is remarkable. We want to understand all the ways in which the planet’s long-term climatic stability can be disrupted – and all the ways (not just Earth’s) that it can be preserved. This quest defines a new field of comparative planetary habitability. “
The new study was published Monday (April 26) in PNAS. You can read it for freebecause PNAS is an open access journal.
Mike Wall is the author of “There“(Grand Central Publishing, 2018; illustrated by Carl Tate), a book on the quest for alien life. Follow it on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.