‘Ocean’ of water found deep underground on Mars

There is new evidence pointing to a secret reservoir of water deep beneath the surface of Mars.

The international study involving researchers from The Australian National University (ANU) could change what we know about the Red Planet.

The study’s findings come from analysing seismic data gathered by the NASA Mars InSight mission. This analysis showed seismic waves slow down in a layer between 5.4 and 8 kilometres below the surface, which could be because of the presence of liquid water.

According to co-author Professor Hrvoje Tkalčić, it’s estimated the inferred volume of hidden water could form a global ocean 520 – 780 metres deep – exceeding the volume of water that would be formed if Antarctica’s ice sheet melted.

“This also matches estimates of the ‘missing’ water on Mars from other studies,” he says.

“Liquid water was abundant on Mars during the Noachian and Hesperian periods – around 4100 to 3000 million years ago – but vanished as the planet transitioned to become the cold, dry environment we see today.”

“Our study indicates it’s possible that much of that ancient water percolated through the porous surface rocks and was retained underground.”

The examination done by Tkalčić and his colleagues of the seismic waves that reverberate through the Martian crust revealed a low-velocity layer – or a layer of rock through which seismic waves passed slowly. This is compatible with a water-saturated, porous layer of rock.

This layer was detected by looking closely at seismic waves generated by meteorite impacts and one of the largest recorded marsquakes.

Tkalčić says a significant number of the planetary science community believes Mars was once much more habitable than it is now.

“Future missions with seismometers and drills are needed to confirm the presence of the water at these depths and gather more clues,” Tkalčić says.

The study was a collaboration between ANU, as well as scientists in China and Italy.

The research has been published in National Science Review.