Scientists find underground liquid water reservoir on Mars

Researchers have found evidence for a large underground pool of liquid water on Mars – enough to cover the whole planet.

Using data collected by Nasa’s Insight lander from 2018 to 2022, the scientists estimated that the amount of groundwater could cover all of Mars to a depth of about a mile.

But the experts say the reservoir is unlikely to be of much use to anyone hoping to supply a future Mars colony.

It is trapped in tiny cracks and pores in rock in the middle of the Martian crust, between 11.5 and 20 kilometres below the surface. Even on Earth, drilling a hole a kilometre deep is a challenge.

Vashan Wright, an assistant professor at UC San Diego’s Scripps Institution of Oceanography, said: “Understanding the Martian water cycle is critical for understanding the evolution of the climate, surface and interior.

“A useful starting point is to identify where water is and how much is there.”

The lander gathered information from the ground directly beneath it, including on the speed of Marsquake waves.

Scientists have sent many probes and landers to Mars to find out where the water that was on the planet some three billion years ago went, as well as when it disappeared and whether life ever existed on the planet.

Much of Mars’ water was thought to have evaporated into space, but experts say these findings are an indication that the water did not escape into space but filtered down into the crust.

Using a model informed by a mathematical theory of rock physics, the researchers determined that the presence of liquid water in the crust most plausibly explained the data.

“While available data are best explained by a water-saturated mid-crust, our results highlight the value of geophysical measurements and better constraints on the mineralogy and composition of Mars’ crust,” the authors wrote

“A useful starting point is to identify where water is and how much is there.”

The findings are published in the Proceedings of the National Academy of Sciences journal.