Liquid water reservoir found deep in Martian rocks

 Huge underground 'stable liquid water' reservoir found on Mars     

A recent study unveiled by NASA's InSight lander has found a massive reservoir of liquid water beneath Mars' surface, potentially capable of covering the planet in a global ocean. Seismic data suggest this water, located 7.2 to 12.4 miles deep, may indicate conditions favourable for microbial life. "Temperatures on present-day Mars become warm enough for stable liquid water near the top of mid-crust, and pores are expected to have closed at the bottom of the layer," the study said. The discovery comes from analysis of data from NASA's Insight lander, which took a seismometer to Mars. Scientists have discovered a reservoir of liquid water on Mars, deep in the rocky outer crust of the planet. The findings come from a new analysis of data from NASA’s Mars Insight Lander, which touched down on the planet back in 2018. The lander carried a seismometer, which recorded four years' of vibrations - Mars quakes - from deep inside the Red Planet. Analysing those quakes, and exactly how the planet moves, revealed "seismic signals" of liquid water.

This ground breaking finding, based on data from NASA's InSight lander, suggests that the Martian subsurface might offer conditions conducive to microbial life, either in the past or present. The Insight mission set out to investigate the evolution of rocky planets, including Earth and Mars. While there is water frozen at the Martian poles and evidence of vapour in the atmosphere, this is the first time liquid water has been found on the planet. The findings are published in the Proceedings of the National Academy of Sciences. Insight's scientific mission ended in December 2022, after the lander sat quietly listening to "the pulse of Mars" for four years. In that time, the probe recorded more than 1,319 quakes. By measuring how fast seismic waves travel, scientists have worked out what material they are most likely to be moving through.

Located approximately 7.2 to 12.4 miles (11.5 to 20 km) below the surface, this water is trapped within fractured igneous rocks. At these depths, the temperature is warm enough to sustain liquid water, unlike the surface, where water would be frozen. "Temperatures on present-day Mars become warm enough for stable liquid water near the top of mid-crust, and pores are expected to have closed at the bottom of the layer," the study said. Planetary scientist Vashan Wright from the University of California, San Diego, and lead author of the study, explained that the presence of liquid water deep within the Martian crust was determined by analysing the speed of seismic waves. These waves change speed based on the rock composition, presence of cracks, and what fills them. "These are actually the same techniques we use to prospect for water on Earth, or to look for oil and gas," explained Prof Michael Manga, from the University of California, Berkeley, who was involved in the research. The analysis revealed reservoirs of water at depths of about six to 12 miles (10 to 20km) in the Martian crust.

The data indicates that a mid-crustal layer of cracked rocks filled with liquid water best explains both the seismic and gravity data collected by InSight. Wright noted, "If the InSight location is representative, extracting all the water from these fractures could fill a global ocean 1 to 2 km's deep." Prof Manga added that water was "the most important molecule in shaping the evolution of a planet". This finding, he said, answers a big question of "where did all the Martian water go?".  Studies of the surface of Mars - with its channels and ripples - show that, in ancient times, there were rivers and lakes on the planet. “Understanding the Martian water cycle is critical for understanding the evolution of the climate, surface and interior,” said lead researcher Dr Vashan Wright, from UC San Diego’s Scripps Institution of Oceanography.

But for three billion years, it has been a desert. Some of that water was lost to space when Mars lost its atmosphere. But, said Prof Manga, here on Earth, "much of our water is underground and there's no reason for that not to be the case on Mars too". The Martian surface has evidence of ancient rivers and lakes etched into it. The Insight probe was only able to record directly from the crust beneath its feet, but the researchers expect that there will be similar reservoirs across the planet. If that is the case, they estimate that there is enough liquid water on Mars to form a layer across the surface that would be more than half a mile deep. However, they point out, the location of this Martian groundwater is not good news for billionaires with Mars colonisation plans who might want to tap into it. "It's sequestered 10-20km deep in the crust," explained Prof Manga. "Drilling a hole 10km deep on Mars, even for [Elon] Musk, would be difficult," he said. The discovery could also point to another target for the ongoing search for evidence of life on Mars. "Without liquid water, you don't have life," said Prof Manga. "So if there are habitable environments on Mars, those may be now deep underground."

Outcome of Mars exploration

The discovery of such a vast underground water reservoir has significant implications for our understanding of Mars' history and its potential to support life. More than 3 billion years ago, Mars was a warm and wet planet with rivers, lakes, and possibly oceans. This study suggests that instead of escaping into space, much of that ancient water seeped into the crust. "Large volumes of liquid water transiently existed on the surface of Mars more than 3 billion years ago. Much of this water is hypothesized to have been sequestered in the subsurface or lost to space," the study explains.  This historical movement of water suggests that the Martian crust could have been water-rich from its early history. The presence of subsurface water also holds promise for future human exploration. While Mars harbors ice at its poles, accessing this underground liquid water could be challenging due to its depth. Drilling to these depths is a formidable task, but researchers propose investigating regions like Cerberus Fossae, where geological activity might expel water to the surface.

Future Plans

The findings from InSight's data provide a tantalizing glimpse into the possibilities for life on Mars. While the existence of water doesn't guarantee life, it creates environments which could potentially support microbial life. The study, titled "Liquid water in the Martian mid-crust" was published in the journal Proceedings of the National Academy of Sciences and was authored by Matthias Morzfeld and Michael Manga and included contributions from researchers at the University of California, San Diego and Berkeley.