- Mars probably had liquid water on its surface billions of years ago. But Mars’ water disappeared over time, leaving the planet cold and dry. Where did Mars’ water go?
- Could water now lie below Mars’ surface? New research from from Scripps Institution of Oceanography – based on data from NASA’s InSight lander – suggests this possibility.
- Mars’ underground water might be enough to form a global ocean, these scientists say, if it were on the surface.
Oceans of water on Mars, underground?
There is ample evidence today for liquid water on Mars a few billion years ago. But today’s Mars is a frozen desert. Where did its water go? A new study, led by Vashan Wright, a geophysicist at UC San Diego’s Scripps Institution of Oceanography, provides potential evidence of water – lots of it – deep below the surface in the crust. The findings are based on data from NASA’s now-defunct InSight mission. The researchers said on August 12, 2024, that Mars’ mid-crust may be saturated with water, enough to form a global ocean if that water were on the surface.
The researchers published their peer-reviewed study in the Proceedings of the National Academy of Sciences on August 12, 2024.
Wright posted the news on X on August 12:
? Liquid Ground Water Found on Mars ?
by: Myself, Michael Manga, and Mattias Morzfeldhttps://t.co/FIVXp1IZ0T
— Island Prof ??? (@DrVasshe) August 12, 2024
Water on Mars may lay in ancient aquifers
Mars had rivers, lakes and possibly even oceans. But, billions of years ago, the planet lost all its surface water. Mars’ surface became dry, cold and inhospitable. Scientists have come up with hypotheses about where all the water went. There is evidence that some of it escaped into space. But much of it might also have simply seeped underground. The new findings – if confirmed – would seem to validate that possibility. As the paper stated:
Large volumes of liquid water transiently existed on the surface of Mars more than three billion years ago. Much of this water is hypothesized to have been sequestered in the subsurface or lost to space.
The new study says that most of Mars’ water is still underground today, and is liquid, not just ice. We already know of extensive ice deposits both on the surface at the poles and below the surface as well. This study, however, focuses on the mid-crust, deeper down than where the ice deposits are. The depth is between 7 to 13 miles (11 to 20 km). The data came from NASA’s InSight lander, which studied the Martian interior: the crust, mantle and core. These data, along with data from Mars rovers, help scientists understand how Mars evolved, how much water it once had and how much water may still exist. Wright 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 study estimated there is enough water to fill a planet-wide ocean about 1 mile (1.6 km) deep.
Using @NASAInSight data, a new analysis led by Scripps Oceanography geophysicist Vashan Wright (@DrVasshe) provides the best evidence to date that Mars contains liquid water deep in its crust. Learn more about the study published in @PNASNews. ?? https://t.co/8O6rntesZ8 pic.twitter.com/SQQJaqhTvY
— Scripps Institution of Oceanography (@Scripps_Ocean) August 12, 2024
![Part of Mars with its orangish surface and white polar cap against a black background.](https://earthsky.org/upl/2024/05/Mars_during_the_2023_solar_conjunction-ESA-CC-BY-SA-3.0-IGO.jpg)
Liquid water most likely explanation
InSight ended its mission in December 2022, after too much dust finally deprived the solar-powered lander of enough power. But during the four years it operated, it collected enormous amounts of data about the inside of Mars. This included detecting thousands of marsquakes, the equivalent of earthquakes on our planet. By measuring the speeds at which the seismic waves move below the surface, scientists can determine what kinds of rocks, ice or other material are present. The research team used a model informed by a mathematical theory of rock physics. The result? the researchers determined that the presence of liquid water in the crust most likely explained the data from InSight. The paper said:
A mid-crust composed of fractured igneous rocks saturated with liquid water best explains the existing data. Our results have implications for understanding Mars’ water cycle, determining the fates of past surface water, searching for past or extant life, and assessing in situ resource utilization for future missions. 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.
Warmer temperatures deep in the crust
While ice deposits are common in the near-surface of Mars, the potential liquid water is deeper down, in the mid-crust, where temperatures are warmer. The paper stated:
Liquid water in the pores of the mid-crust also requires high enough permeability and warm enough temperatures in the shallow crust to permit exchange between the surface and greater depths.
The researchers even postulate that there should be more water in the mid-crust zone than the amounts proposed to have filled the hypothesized ancient Martian oceans. That’s a lot of water!
![Cutaway view of the interior of a planet, with labeled layers of crust shown.](https://earthsky.org/upl/2024/08/Mars-interior-cutaway-view-illustration-InSight-August-12-2024.jpeg)
A window to past Mars and possible home for life
If there really is an ocean’s worth of water inside Mars, then that provides fascinating clues about the planet’s past. Co-author Michael Manga of UC Berkeley said:
Establishing that there is a big reservoir of liquid water provides some window into what the climate was like or could be like. 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.
![Water on Mars: Complex robot-like machine with 2 large solar panels sitting on reddish sandy terrain, seen from above.](https://earthsky.org/upl/2024/08/InSight-selfie-Mars-December-6-2018.jpg)
Bottom line: Where did Mars’ water go? A new study using data from NASA’s InSight mission provides evidence for oceans of water on Mars, deep below the surface in the crust.
Source: Liquid water in the Martian mid-crust
Via Scripps Institution of Oceanography