Illustration of Mars on a black background. (Photo: Science Image Library)

Geophysicists have discovered a giant ocean hidden beneath the surface of Mars and they think it could harbor life.

The giant underground lake, discovered using seismic data collected by NASA's InSight lander, contains enough liquid to cover the entire planet with a mile of water. However, it is too deep to be reached by any known means.

Trapped inside a layer of fractured rock 11.5 to 20 kilometers below the Martian crust, accessing the water would require a drilling operation that is currently impossible on Earth.

“Water is essential for life as we know it. I don’t see why underground reservoirs wouldn’t be habitable environments. That’s certainly true on Earth — deep mines harbor life, the ocean floor harbors life,” said study co-author Michael Manga, professor of earth and planetary sciences at UC Berkeley.

"We have not found any evidence of life on Mars, but at least we have identified a place that could in principle sustain life," Manga added.

River channels, deltas and dried lake beds crisscross the surface of Mars, providing scientists with clear evidence that water once existed in abundance on the surface of the barren planet. However, about 3.5 billion years ago, a sudden change in Mars' climate stripped the water from its surface.

Rapid drying out

The cause of the rapid drying is still unclear, although scientists have hypothesized that it could have been caused by a sudden loss of the planet’s magnetic field, an asteroid impact, or ancient microbial life disrupting the planet due to climate change. Coming up with a proper explanation and figuring out where the water went has become a key question.

By feeding this data into a mathematical model similar to the one used to find underground water aquifers and oil deposits on Earth, scientists mapped the interior of Mars to figure out the thickness of the crust, the depth of the core, the composition of the core, and even a bit about the temperature inside the mantle, Manga said.

Further investigation of the crust suggests that it most likely consists of a fragment of broken-up igneous rock containing enough liquid water to fill Mars’ oceans, a sign that the water did not escape into space billions of years ago, but instead dripped down into the planet’s crust.

Currently, accessing the secret ocean is beyond human engineering capabilities (the deepest hole ever dug on Earth, the Kola Superdeep Borehole, only dug 7.6 miles into our planet's surface), but it's not the only place scientists are looking for life on Mars.

NASA had originally planned for a sample return mission to launch around 2026, but that date was pushed back to 2040 due to budget concerns. The agency is now soliciting proposals from private companies to speed up the mission.

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According to Live Science