More Liquid Water Has Been Found Beneath the Surface of Mars: This Time, It’s a Whole Ocean

Although news of the presence of water on Mars is nothing new, the discovery of a massive amount of liquid water—enough to cover the planet’s surface in a mile-deep ocean—has been made by a team that used seismic data to map the interior of the Red Planet.

Using data collected by the sensors aboard NASA’s InSight lander, the team analyzed seismic data gathered from marsquakes generated by meteor strikes and seismic shifts between 2018 and 2022 to map of the interior of the Red Planet. Using a mathematical model similar to ones used to discover aquifers and petroleum deposits here on Earth, the team mapped out “the thickness of the crust, the depth of the core, the composition of the core, even a little bit about the temperature within the mantle,” according to study co-author Michael Manga, a professor of earth and planetary science at UC Berkeley.

Their model yielded an interesting result: the presence of a patchwork of fragmented igneous rock 11.5 to 20 kilometers (7 to 13 miles) below the Martian surface that contains enough liquid to cover the planet’s surface in an ocean one to two kilometers (0.6 to 1.2 miles) deep. While it was assumed that the oceans that dominated the surface of Mars billions of years ago eventually evaporated into space, it may turn out that the water may have trickled down into the depths of the planet instead.

Additionally, a reservoir of liquid water this substantial may also be a promising target to look not only for signs of ancient Martian life, but also for lifeforms that may still be thriving, miles below the surface.

“Water is necessary for life as we know it,” Manga pointed out. “I don’t see why [the underground reservoir] is not a habitable environment. It’s certainly true on Earth—deep, deep mines host life, the bottom of the ocean hosts life.”

“We haven’t found any evidence for life on Mars, but at least we have identified a place that should, in principle, be able to sustain life,” he added.

Unfortunately, reaching such a depth may be beyond our current technological capabilities: the Kola Superdeep Borehole, a 12.3-kilometer (7.6-mile) deep hole bored into the crust below Russia’s Kola Peninsula, was drilled in three phases over the course of 19 years to reach as deep as the upper layers of the suspected Martian water deposits, an engineering endeavor that would likely prove to be impossible for explorers working on Mars’ surface. But more immediately, the discovery of such a large amount of water on Mars adds to our understanding of how the planet evolved.

“Understanding the Martian water cycle is critical for understanding the evolution of the climate, surface and interior,” explained Vashan Wright, an assistant professor at UC San Diego’s Scripps Institution of Oceanography. “A useful starting point is to identify where water is and how much is there.”