• Although Mars lost its surface oceans billions of years ago, a new study from UC Berkeley suggests that there’s lots of water deep within the planet’s crust.
  • After analyzing data gathered from NASA’s InSight lander, the team’s mathematical models have suggested that water trapped with fractured igneous rock could cover the planet in a one-mile-thick ocean.
  • Sadly, this water is located roughly 7 to 13 miles below the surface—a drilling depth that’d be incredibly difficult on Earth, let alone Mars.

It’s no secret that Mars contained—and currently contains—lots of water. Before the planet lost most of its atmosphere and its magnetic field, Mars likely contained flowing rivers and oceans much like its blue marble neighbor next door. The Red Planet eventually lost some H20 to evaporation, but a new study suggests that a lot of water is still locked away deep within the planet’s crust.

Analyzing seismic data gathered from NASA’s InSight lander, which arrived at Mars at the tail end of 2018, scientists from the University of California Berkeley concluded that it’s likely that Mars contains enough water deep within its crust to cover the entire planet with an ocean nearly one mile thick. The results of the study were published this week in the journal Proceedings of the National Academy of Sciences (PNAS).

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Scripps Institution of Oceanography
A slice of the Martian crust, detailing the fractured igneous rock that contains water.

“Understanding the Martian water cycle is critical for understanding the evolution of the climate, surface, and interior,” study co-author Vashan Wright, previously a postdoctoral fellow at UC Berkeley and now an assistant professor at UC San Diego, said in a press statement. “A useful starting point is to identify where water is and how much is there.”

Finding water within Mars’ crust wasn’t exactly the primary mission of the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander, though it certainly falls within its purview. NASA describes InSight’s mission, which officially wrapped up in 2022, as measuring “the planet’s vital signs: its pulse, temperature, and reflexes.” While other missions explored canyons, volcanoes, and the geochemistry of Mars’ topsoil, InSight probed its geologic depths for evidence of tectonic activity and answers to lingering questions about how rocky planets formed around our Sun.

In this new study, scientists used seismic data collected by InSight and created mathematical models to explore the possible interior of Mars, employing the same methods that industries use to find underground aquifers and oil fields on Earth. According to these calculations, Mars contains a deep layer of fractured igneous rock with cracks that are saturated with liquid water. And where there’s water, there’s always a chance to find some form of (likely microbial) life lurking nearby.

“Establishing that there is a big reservoir of liquid water provides some window into what the climate was like or could be like,” UC Berkeley’s Michael Manga, a co-author of the study, said in a press statement. “And water is necessary for life as we know it. 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.”

And this water isn’t a mere trickle—in fact, if future astronauts could somehow pump out all of it, it’d likely fill entire oceans across Mars that are around one mile thick. However, the scientists behind this new study assert that such a feat is likely impossible.

While fresh groundwater on Earth can typically be found anywhere from 500 to 1,000 meters down, the researchers estimate that this water is likely located somewhere 11.5 and 20 kilometers, or around 7 to 13 miles, underground. That’s as deep (on the low end) as the deepest hole ever dug by humans on Earth—doing so on Mars is likely an engineering and logistical impossibility (at least, for now).

But confirming and analyzing this vast reservoir of water deep within the Martian crust will be essential for understanding the planet’s overall composition, geologic history, and ancient climate. So, while this locked away water probably won’t sustain future Martian colonies, it’s certainly quenching our never-ending thirst for knowledge about our planetary neighbor.

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