Floods of unimaginable magnitude once washed through Gale Crater on Mars around 4 billion years ago, raising the possibility life once existed on the Red Planet.
Dubbed a ‘raging megaflood’ by scientists, it was likely caused by an asteroid or comet hitting the planet, heating and unleashing ice stored on the Martian surface.
Water as much as 78ft deep raged across the crater at 32 feet per second, leaving behind gigantic ripples that are tell-tale structures familiar to scientists on Earth.
On Earth where water is found ‘there is life’, according to co-author Alberto G. Fairen, and on Mars four billion years ago microbial life may have developed, he said.
Dubbed a ‘raging megaflood’ by scientists, it was likely caused by an asteroid or comet hitting the planet, heating and unleashing ice stored on the Martian surface
This close up image of rocks on Mars show changes in the bed interval including rounded coarse sand and pebble fragments suggesting water once flowed through the area
The ripples created by flooding – also known as antidunes – are up to 30ft high and spread about 450ft apart, according to Ezat Heydari, co-author.
As is the case on Earth, geological features including the work of water and wind have been frozen in time on Mars for about four billion years – they convey processes that shaped the surface of both planets in the distant past.
This includes the occurrence of the giant wave-shaped features in sedimentary layers of Gale crater, often called ‘megaripples’ or antidunes.
In one instance that water entered Gale Crater, and when combined with water coming down from Mount Sharp in Gale Crater, produced gigantic flash floods
‘We identified megafloods for the first time using detailed sedimentological data observed by the rover Curiosity,’ said co-author Alberto G. Fairén.
‘Deposits left behind by megafloods had not been previously identified with orbiter data,’ Fairen explained.
The antidunes seen in data from NASA Curiosity are identical to the features formed by melting ice on Earth about two million years ago, Heydari said.
On Mars releasing the stocks of frozen water likely required a significant impact event that released carbon dioxide, methane and the ice as water vapour.
The water vapour and gases combined to produce a short warm and wet period that could have resulted in the development of life, researchers claim.
‘The warm and wet climate persisted even after the flooding ended, but its duration cannot be determined by our study,’ the team wrote in their paper.
The condensation from the heat generated by the impact likely formed clouds of water vapour which created torrential rain – possibly across the planet.
An earlier study, also using data from Curiosity, revealed evidence of storms that filled lakes and rivers with rainfall on the planet – about four billion years ago.
Curiosity sent back images and data for the research team to examine – including the bottom image showing flow direction of the water – along the yellow dotted line
In one instance that water entered Gale Crater, and when combined with water coming down from Mount Sharp in Gale Crater, produced gigantic flash floods.
This left behind deposits of gravel ridges surrounding the crater that can be seen on the Red Planet today – and helped the team work out the scale of the megaflood.
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.
Graphic showing the terrain studied by Curiosity and where layers and antidunes have been discovered – indicating areas of ripples and waves from a megaflood
These are images of the Gale crater showing the various topographic features including the mountains and ripples produced by activity on the planet over billions of years
‘Early Mars was an extremely active planet from a geological point of view,’ Fairén said. ‘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,’ he said. ‘Was it inhabited? That’s a question that the next rover Perseverance … will help to answer.’
Perseverance, which launched from Cape Canaveral on July 30, is scheduled to reach Mars on February 18, 2021.
The findings have been published in the journal Scientific Reports.
NASA MARS 2020: THE MISSION WILL SEE THE PERSEVERANCE ROVER AND INGENUITY HELICOPTER SEARH FOR LIFE
NASA’s Mars 2020 mission will search for signs of ancient life on on the Red Planet in a bid to help scientists better understand how life evolved on Earth.
Named Perseverance, the main car-sized rover will explore an ancient river delta within the Jezero Crater, which was once filled with a 1,600ft deep lake.
It is believed that the region hosted microbial life some 3.5 to 3.9 billion years ago and the rover will examine soil samples to hunt for evidence of the life.
Nasa’s Mars 2020 rover (artist’s impression) will search for signs of ancient life on Mars in a bid to help scientists better understand how life evolved on our own planet
The $2.5 billion (£1.95 billion) Mars 2020 spaceship launched on July 30 witht he rover and helicopter inside – and will land on February 18, 2021.
Perseverance is designed to land inside the crater and collect samples that will eventually be returned to Earth for further analysis.
A second mission will fly to the planet and return the samples, perhaps by the later 2020s in partnership with the European Space Agency.
This concept art shows the Mars 2020 rover landing on the red planet via NASA’s ‘sky-crane’ system