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According to a new study, there could be oceans’ worth of liquid water deep in the rocky outer crust of Mars. While scientists have known about water ice at the Martian poles for a long time, this is the first time they have discovered liquid water on the planet.
The study, ‘Liquid water in the Martian mid-crust’, was published last week in the journal Proceedings of the National Academy of Sciences (PNAS). It was carried out by Vashan Wright, Matthias Morzfeld, and Michael Manga of the University of California San Diego.
The findings could help researchers better understand the water cycle of Mars, which in turn could unlock questions related to the evolution of the planet’s climate, surface, and interior. The discovery could also provide impetus to the ongoing search for evidence of life on Mars.
Here is a look at how the study was carried out and the findings.
How was the study carried out?
For their study, the researchers used the data from NASA’s Mars Insight Lander, which touched down on the planet back in 2018 and retired in December 2022. The lander was equipped with a seismometer, which recorded four years’ of seismic waves — created by Marsquakes and meteorite impacts — deep inside the planet. In total, Insight recorded more than 1,300 quakes while it was active.
The researchers examined the speed of these seismic waves and were able to determine what material they were most likely to be moving through.
To do so, they used “a geophysical model identical to one used to map underground aquifers and oil fields here on Earth, and employed it to analyse data collected by InSight on Mars. They found that the data are best explained if, deep below the surface of Mars, there lies a layer of fractured igneous rock, such as granite, whose cracks are filled with liquid water,” according to a report by New Scientist.
What are the findings?
That layer is located at depths of about 10 to 20 km in the Martian crust. The study suggests that the water could have seeped from the surface billions of years ago when Mars harboured rivers, lakes, and possibly oceans.
Speaking to The Guardian, Vashan Wright, co-author of the study, said, “On Earth, groundwater underground infiltrated from the surface, and we expect this process to have occurred on Mars… The infiltration must have happened during a time when the upper crust was warmer than it is today.”
The researchers said that if the measurements at the Insight Lander location were representative of the whole planet, the amount of water trapped in the rock fractures would fill a 1-2 km-deep ocean on Mars.
Although the discovery of liquid water does not mean that there is life on Mars, it sure raises the possibility of finding a habitable environment.
Michael Manga, co-author of the study, told New Scientist, “[W]ater is necessary for life as we know it. I don’t see why [the underground reservoir] is not a habitable environment. It is certainly true on Earth — deep, deep mines host life, the bottom of the ocean hosts life. We have not 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 discovery, however, is not good news for billionaires like Elon Musk who plans to colonise Mars. The researchers said that it would be a daunting task to drill a 10-20 km deep hole on Mars and extract the water.
