(CNN) – Data from a retired NASA mission revealed evidence of an underground water reservoir deep beneath the surface of Mars, according to new research.
A team of scientists estimates there could be enough water trapped in tiny cracks and pores in the rock in the middle of the Martian crust to fill oceans on the planet’s surface. Groundwater would likely cover the entirety of Mars to a depth of 1.6 kilometers, according to the study.
The data comes from NASA InSight lander which used a seismometer to study the interior of Mars between 2018 and 2022.
Future astronauts exploring Mars would face a whole series of challenges if they tried to access the water, because it is located between 11.5 and 20 kilometers below the surface, according to the study published this Monday in the journal Proceedings of the National Academy of Sciences.
But the finding reveals new details about the geological history of Mars and suggests a new place to look for life on the Red Planet if water ever became accessible.
“Understanding the water cycle on Mars is fundamental to understanding the evolution of the climate, both on the surface and in the interior,” said the study’s lead author, Vashan Wright, an associate professor and geophysicist at the Scripps Institution of Oceanography in Mars, in a statement. the University of California at San Diego. “A useful starting point is to identify where there is water and how much there is.”
Billions of years ago, Mars was likely a warmer, wetter place, based on evidence from ancient lakes, river channels, deltas and water-altered rocks studied by other NASA missions and observed by orbiters. But the Red Planet lost its atmosphere more than 3 billion years ago, effectively ending the wet period on Mars.
Scientists are still unsure why Mars lost its atmosphere, and a multitude of missions have been developed to learn about the history of the planet’s water, where it went, and whether the water ever created habitable conditions for human life on Mars. While water remains trapped as ice in the planet’s polar caps, researchers don’t believe that can explain all of the planet’s “lost” water.
Existing theories offer some likely scenarios for what happened to Martian water after Mars lost its atmosphere: some hypothesize that it turned to ice or was lost to space, while others suggest that it was incorporated into minerals beneath. from the planet’s surface or seeped into deep aquifers.
The new findings suggest that water from Mars seeped into the planet’s crust.
InSight was a stationary lander, but it collected unprecedented data on the thickness of the Red Planet’s crust and the temperature of its mantle, as well as the depth and composition of the core and atmosphere. The lander’s seismometer detected the first earthquakes on the planet, called marsquakes.
While earthquakes occur when tectonic plates shift, move and rub against each other, the Martian crust is like a giant plate with faults and fractures as the planet shrinks and cools over time. As the Martian crust stretches, it cracks. InSight’s seismometer was able to detect more than 1,300 Martian earthquakes rumbling hundreds and thousands of kilometers away.
Scientists studying the InSight data were able to study the speed of the earthquakes as they traveled across the planet, which can serve as an indicator of what substances exist beneath the Martian surface.
The speed of seismic waves depends on what the rock is made of, where it has cracks and what fills those cracks, Wright said.
The team used this data and fed it into a mathematical rock physics model, which is used on Earth to map oil fields and underground aquifers.
The results showed that the InSight data best matches a deep layer of igneous or volcanic rock filled with liquid water.
“Establishing that there is a large reservoir of liquid water provides insight into what the climate was or could be like,” study co-author Michael Manga, a professor of earth and planetary sciences at the University of California, Berkeley, said in a statement.
“Water is necessary for life as we know it. “I don’t see why (the underground warehouse) wouldn’t be a habitable environment,” Manga added. “It is certainly like this on Earth: very deep mines harbor life, the bottom of the ocean harbors life. “We have not found any evidence of life on Mars, but at least we have identified a place that, in principle, should be capable of supporting life.”
If the crust of Mars is similar across the planet, there may be more water within the mid-crustal zone than the “volumes proposed to have filled the hypothetical ancient Martian oceans,” the authors wrote in the study.
Rocks help capture information about a planet’s history, and understanding a planet’s water cycle can help researchers uncover the evolution of Mars, Wright said.
While analysis of the data cannot reveal any information about past or present life – if it existed – on Mars, it is possible that the moist Martian crust is habitable in the same way that Earth’s deep groundwater is hospitable. for microbial life, he said.
But even drilling holes just 1 kilometer or more deep on Earth is a challenge that requires energy and infrastructure, so an enormous amount of resources would need to be brought to Mars to drill at such depths, Wright said.
The team was surprised to find no evidence suggesting the existence of a layer of frozen groundwater beneath Insight, since that part of the crust is cold. Researchers are still trying to determine why there is no frozen groundwater at shallower depths above the middle crust.
The findings add a new piece to the Martian water puzzle.
The idea that liquid water may exist deep beneath the Martian surface has been around for decades, but this is the first time that actual data from a mission to Mars can confirm such speculation, said Alberto Fairén, a visiting interdisciplinary planetary scientist and astrobiologist. from the astronomy department at Cornell University. Fairén did not participate in the study.
He said the water is likely “some kind of deep underground mud.”
“These new results demonstrate that liquid water does exist in the Martian subsoil today, not in the form of discrete and isolated lakes, but as sediments saturated with liquid water, or aquifers,” said Fairén. “On Earth, the subsurface biosphere is truly enormous and contains most of our planet’s prokaryotic diversity and biomass. Some research even points to an origin of life on Earth precisely in the depths of the subsoil. Therefore, the astrobiological implications of finally confirming the existence of liquid water habitats kilometers below the surface of Mars are truly exciting.”
The result is “exactly the kind of thing I was hoping we would get from InSight,” said Bruce Banerdt, the principal investigator for the InSight mission.
“I was hoping that we could get data good enough to do these kinds of studies where we really look at details of the interior of Mars that are relevant to geological questions, questions about the habitability of Mars, questions about the evolution of Mars,” said.
Banerdt, who was not involved in the research, said that while the interpretation of the data presented in the paper is strongly supported by good arguments, he also believes that it is still somewhat speculative and that there is almost always another way to explain any set of data.
“I was very impressed by the fact that Wright and his team incorporated mineral physics concepts to interpret seismic data,” Banerdt said.
Banerdt and Wright expressed interest in being able to send more seismometers to Mars and other planets and moons in our solar system in the future. While InSight’s single seismometer collected crucial data, spreading it across Mars would reveal variations in the planet’s interior and provide a broader view of its diverse and complex history, Banerdt said.
“Just as on Earth, where groundwater is connected to the surface through rivers and lakes, this was surely true on early Mars,” Wright said. “The groundwater we see is a record of that past.”
