Megafloods washed across ancient Mars (and alien life could have flourished there)

Almost unimaginably huge floods washed across Gale Crater on the surface of Mars about four billion years ago - and the finding hints that life might have existed there too.

Data collected by NASA’s Curiosity Rover shows that gigantic ripples on the surface (still visible today) were likely left by a giant flood.

Scientists believe that the flood may have been set off by a meteor impact which melted ice on the surface of the planet.

The impact may have allowed life to briefly flourish on the surface, the researchers say.

Watch: Massive mars dust storms might have stripped away an ocean’s worth of water

Read more: Mysterious “rogue planet” could be even weirder than we thought

“We identified megafloods for the first time using detailed sedimentological data observed by the rover Curiosity,” said co-author Alberto G. Fairén, a visiting astrobiologist at Cornell University.

“Deposits left behind by megafloods had not been previously identified with orbiter data.”

“Early Mars was an extremely active planet from a geological point of view. The planet had the conditions needed to support the presence of liquid water on the surface -- and on Earth, where there’s water, there’s life.

“So early Mars was a habitable planet. Was it inhabited? That’s a question that the next rover Perseverance … will help to answer.”

Geological features including the work of water and wind have been frozen in time on Mars for about 4 billion years.

Read more: Astronomers find closest black hole to Earth

There are giant wave-shaped features in sedimentary layers of Gale crater, often called “megaripples” or antidunes that are about 30 feet high and spaced about 450 feet apart, according to lead author Ezat Heydari, a professor of physics at Jackson State University.

The antidunes hint at flowing megafloods at the bottom of Mars’ Gale Crater about 4 billion years ago.

They are identical to the features formed by melting ice on Earth about 2 million years ago, Heydari said.

The most likely cause of the Mars flooding was the melting of ice from heat generated by a large impact, which released carbon dioxide and methane from the planet’s frozen reservoirs.

The water vapor and release of gases combined to produce a short period of warm and wet conditions on the red planet.

Read more: What are fast radio bursts, and why do they look like aliens?

Condensation formed water vapor clouds, which in turn created torrential rain, possibly planetwide.

The Curiosity rover science team has already established that Gale Crater once had persistent lakes and streams in the ancient past. These long-lived bodies of water are good indicators that the crater, as well as Mount Sharp within it, were capable of supporting microbial life.

Watch: China launches robotic spacecraft to the moon