NASA’s InSight Discovers Subsurface Oceans on Mars

Geophysicists, leveraging seismic data from NASA’s Insight lander, have unveiled a significant subterranean water reservoir on Mars, potentially adequate to have once sustained extensive ancient oceans.

This reservoir, ensnared in Mars’ mid-crust, suggests that the planet’s water did not entirely dissipate into space but permeated its crust, challenging previous notions of Martian aridity and potentially fostering a habitat conducive to life.

By employing seismic activity to explore Mars’ interior, geophysicists have detected signs of a substantial underground liquid water reservoir — enough to inundate the planet’s surface with oceans.

Data from NASA’s Insight lander have enabled these scientists to estimate that this subterranean water volume could submerge the entire planet at a depth between 1 and 2 kilometers, or roughly a mile.

Although promising in unraveling Mars’ water destiny following the disappearance of its oceans over 3 billion years ago, this reservoir remains challenging to access for sustaining a potential future Mars settlement. Situated in minute crevices and pores within rock in the middle of Mars’ crust, 11.5 to 20 kilometers below the surface, drilling to such depths presents a formidable task, even on Earth.

Implications for Martian Settlement and Astrobiology

While this discovery signifies a promising area to investigate Martian life if access to the reservoir is viable, it primarily provides answers regarding the planet’s geological narrative.

“Comprehending Mars’ water cycle is paramount to deciphering the planet’s climate, terrain, and subterranean structure,” commented Vashan Wright, a former UC Berkeley postdoctoral fellow now serving as an assistant professor at UC San Diego’s Scripps Institution of Oceanography. “A logical starting point involves identifying water locations and quantities.”

Wright, in collaboration with Michael Manga of UC Berkeley and Matthias Morzfeld of Scripps Oceanography, elucidated their findings in a forthcoming article in the journal Proceedings of the National Academy of Sciences.

Methodologies and Hypotheses: Unveiling Martian Geology

Through a sophisticated mathematical model of rock physics, akin to Earth’s methodologies for mapping subterranean aquifers and oil fields, investigators have inferred that the seismic data from Insight best align with a deep layer of fractured igneous rock saturated with liquid water. Igneous rocks are solidified magma, such as the granite found in the Sierra Nevada range.

“Corroborating the existence of a vast liquid water reservoir offers insights into past and potential Martian climate,” remarked Manga, a UC Berkeley professor specializing in earth and planetary science. “Given water’s vital role in sustaining life, the underground reservoir could constitute a habitable environment. Analogously, Earth’s deep mines and ocean depths harbor life. While we await evidence of life on Mars, we have pinpointed a plausible habitat to nurture life.”

Manga was Wright’s postdoctoral mentor, while Morzfeld, formerly a postdoctoral fellow at UC Berkeley’s mathematics department, now serves as an associate professor of geophysics at Scripps Oceanography.

Traces of Ancient Water and Mars’ Geologic Evolution

Multiple indicators — including river networks, deltas, lake sediments, and water-influenced rocks — support the premise of past water flow on Mars’ surface. However, this aqueous phase ended over 3 billion years ago when Mars underwent atmospheric loss. Deciphering what transpired to this water, its timing, and the potential existence of Martian life remain focal points for planetary scientists on Earth.

The recent findings propose that a significant portion of the water didn’t dissipate into space but percolated downward into the crust.

The Insight lander embarked on its Mars mission in 2018 under NASA’s aegis to scrutinize the planet’s crust, mantle, core, and atmosphere while offering invaluable insights into Mars’ interior before concluding its mission in 2022.

“The mission surpassed my expectations significantly,” reflected Manga. “Analyzing the seismic data collected by Insight, researchers deduced the crust thickness, core depth, core composition, and even gleaned insights into mantle temperatures.”

Insight’s discoveries encompassed Mars quakes up to a magnitude of 5, meteorite impacts, and volcanic tremors, all generating seismic waves that facilitated geophysicists in delving into the planet’s internal composition.

An earlier report indicated the absence of water ice in the upper crust above a 5-kilometer depth, diverging from Manga’s expectations. This implies limited accessible frozen groundwater beyond the planet’s polar regions.

The latest study focused on the deeper crust and concluded that the “available data are best explained by a water-saturated mid-crust” beneath Insight’s position. Assuming crust uniformity across Mars, the team inferred a greater water presence in this mid-crust region compared to the volumes envisioned for ancient Martian oceans.

For further insights on this revelation, refer to the article “Did We Just Find Liquid Water on Mars? NASA InSight Lander’s Surprising Data.”

Reference: “Liquid Water in the Martian Mid-Crust” 12 August 2024, Proceedings of the National Academy of Sciences.
DOI:10.1073/pnas.2409983121

The Canadian Institute for Advanced Research, the National Science Foundation, and the U.S. Office of Naval Research provided support for this research.