- Mars has a lot of water in its depths.
On Mars, rock layers at depths of 10 to 20 kilometers contain enough water to fill a one to two kilometer deep ocean across the entire planet. A team led by Vashan Wright of the University of California, San Diego, discovered this underground water reservoir while analyzing data from the Mars lander "InSight".
"Over three billion years ago, there was abundant liquid water on the surface of Mars," Wright and his colleagues explain in the "Proceedings" of the U.S. National Academy of Sciences ("PNAS"). Evidence of this includes numerous traces of riverbeds, lakes, and a vast ocean seen in Mars probe images. It's still unclear where all this water went after Mars lost most of its atmosphere. One theory suggests that a significant portion of the water may have seeped into the subsurface.
To investigate this hypothesis, Wright and his team reanalyzed "InSight" data and compared it with various models for water-bearing rock layers. The Mars lander, equipped with a seismometer – a device for measuring ground tremors – provided a glimpse into the interior of the Red Planet from 2018 to 2022. The propagation of seismic waves caused by Marsquakes or meteorite impacts offers researchers detailed insights into the planet's internal structure.
However, this water would be of little use to future Mars colonists – firstly due to its great depth, and secondly because the water is hidden in the pores and cracks of the rock, making it difficult to extract.
Nevertheless, such a layer would be significant: Even at great depths on Earth, microorganisms can be found in rocks. "Water is essential for life as we know it," emphasizes Wright's colleague Michael Manga. "It's therefore not far-fetched to assume that the water-bearing rock layers on Mars could also provide a habitable environment for microbes." The team therefore considers these deep Mars rock layers a prime target in the search for microbial life on our neighboring planet.
The vast ocean seen in Mars probe images is evidence of abundant liquid water on Mars' surface in the past. This discovery of water in subsurface rock layers on Mars could potentially provide a habitable environment for microbes at great depths.
