Ancient ‘megaflood’ on Mars shows planet was once capable of supporting life

When NASA’s Perseverance rover lands in the Gale Crater on Mars early next year, it will set about searching for evidence of ancient life there. We know that Mars once had copious liquid water on its surface and that the presence of liquid water is a key indicator that the area could have been hospitable to life.

Now, a new study finds that the Gale Crater was the site of an ancient ‘megaflood,’ providing more evidence that this particular location could once have been habitable.

Enormous floods washed through the Gale Crater around 4 billion years ago, according to data collected by Perseverance’s sibling rover, Curiosity. The rover found signs of deep ripple structures in the martian rock, called megaripples, which are 30 feet high and spaced 450 feet apart. These are similar to structures found here on Earth, caused by the melting of ice here 2 million years ago.

This is the first time evidence of megafloods has been observed on Mars, according to co-author Alberto G. Fairén. Even studies using data from orbiters had not seen the deposits, so they needed the Curiosity rover to spot them.

This composite, false-color image of Mount Sharp inside Gale crater on Mars shows geologists a changing planetary environment. On Mars, the sky is not blue, but the image was made to resemble Earth so that scientists could distinguish stratification layers.
This composite, false-color image of Mount Sharp inside Gale crater on Mars shows geologists a changing planetary environment. On Mars, the sky is not blue, but the image was made to resemble Earth so that scientists could distinguish stratification layers. NASA/JPL

The researchers believe that the enormous floods may have been kicked off when the planet was impacted by a meteorite, the heat of which caused ice to melt and release carbon dioxide and methane. This sudden rush of gases into the atmosphere made Mars warm and wet for a short time, with torrential rain pouring down on the planet and causing floods into craters like the Gale Crater.

The exciting part of this news is that it indicates that Mars in general, and the Gale Crater in particular, was once capable of supporting life.

“Early Mars was an extremely active planet from a geological point of view,” Fairén said in a statement. “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.”

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