A study published late last year found “seismic fractures in the Martian crust” that scientists believe could be an indicator of liquid water beneath the Martian surface, raising the possibility that microbial life could exist on the Red Planet.
With a long history similar to Earth’s and relative proximity to our world, Mars has been an attractive destination for astrobiological research for decades. The team’s work suggests that liquid water—essential for life as we know it—may be stored beneath the Martian surface, bolstering the idea that microbial life could continue to thrive beneath the planet’s arid and rocky topsoil.
“If liquid water exists on Mars,” said Ikuo Katayama, a planetary scientist at Hiroshima University and co-author of the study, in a paper published by the Geological Society of America, “it could mean the presence of microbial activity” in the Martian crust.
Mars rovers, landers and orbiters are designed to study every aspect of the Red Planet, and all their data are shedding some light on the possibility of life on Mars, even if it is long extinct. For the past four years, the Perseverance rover has been traveling along the western rim of Jezero Crater, a vast depression on the planet that once held a lake of liquid water billions of years ago. Along the way, Perseverance has collected intriguing Martian rocks that NASA plans to return to Earth as part of its Mars Sample Return program.
InSight landed on Mars in November 2018 and was tasked with digging into the Martian topsoil, listening to winds and dust storms on the planet’s surface, and—perhaps most productively—listening to the Martian interior for signs of seismicity. Before the lander was decommissioned in December 2022, InSight had detected more than 1,300 Martian earthquakes and sent back nearly 7,000 images of the planet’s surface.
Some of the seismic data InSight collected indicated boundaries at depths of 6.2 miles (10 kilometers) and 12.4 miles (20 kilometers) below the planet’s surface, which had previously been interpreted as sudden changes in the porosity of rocks. But the authors of the paper argue that the visible boundary could be cracks in the Martian interior that are filled with water.
The team measured how different types of seismic waves that originate on Mars travel through similar rocks in Sweden. The team’s experiments showed that the speed of seismic waves through dry, wet and frozen samples is significantly different – so the boundaries at the two Martian depths could indicate the change of dry rock in the Martian interior to moisture. Hence, the presence of liquid water on Mars.
“Many studies indicate the presence of water on ancient Mars billions of years ago,” Katayama said in a press release, but “our model indicates the presence of liquid water on modern Mars.”
InSight’s instrument, the Martian rover, has been unable to penetrate the Martian surface, which has hampered NASA’s bold ambition to understand the planet’s interior.
If NASA returns samples from Mars without a hitch, studying the Perseverance sample vault could be extremely useful in determining whether life ever existed on Mars. But given the team’s recent findings, the agency may want to consider sending a rover to the Red Planet.
