Evrim Yazgin
Cosmos science journalist
Nearly 2 years since NASA’s InSight Lander mission ended, the space robot’s geological data continues to provide insights into the interior of Mars.
Scientists believe that buried in InSight’s data is evidence of an ocean of liquid water on Mars. While the finding may have implications for the potential habitality of Mars, the underground ocean is 11.5 to 20km beneath the surface – too far to be useful for future human expeditions.
On Earth, the deepest drills barely go beyond 1km.
Even so, it is the best evidence to date that the Red Planet still has liquid water in addition to the water locked in its frozen poles.
The analysis is published in the journal Proceedings of the National Academy of Sciences.
“Understanding the Martian water cycle is critical for understanding the evolution of the climate, surface, and interior,” says lead researcher Vashan Wright, a geophysicist the University of California San Diego’s (UCSD) Scripps Institution of Oceanography. “A useful starting point is to identify where water is and how much is there.”
Wright’s team used a mathematical model to analyse the physical properties of rocks – identical to those used to map underground water and oil on Earth.
They concluded that seismic data from InSight suggests liquid water in the Martian crust.
“Establishing that there is a big reservoir of liquid water provides some window into what the climate was like or could be like,” says Michael Manga, a UC Berkeley professor of earth and planetary science. “And water is necessary for life as we know it.”
Manga says he’s not ruling out that the underground reservoir is 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.”
The scientists estimate that the amount of groundwater detected is enough to cover the entire planet with water to a depth of between 1 and 2 kilometres.
Discoveries of ancient lakes, river deltas and flowing channels on Mars makes clear that the planet once supported liquid water. That wet period is believed to have ended about 3 billion years ago.
InSight’s data suggests that Mars’s water did not escape into space but is still on – or in – the Red Planet.
