The Martian permafrost may be hiding veins of habitable liquid water

Evidence suggests that Mars might have a system of liquid water coursing through its frozen substrate. Just like permafrost on Earth, Martian ice is thought to conceal thin veins of liquid water, which could be substantial enough to sustain microbial life.

“Mars teeters on the brink of potential habitable conditions, and my initial hypothesis was that sufficient water for microbial life was almost impossible to find,” states Hanna Sizemore from the Planetary Science Institute in Arizona. “My findings surprised me.”

With the data obtained from Martian soil, Sizemore and her team estimated the volume of liquid that could exist within the icy terrain and evaluated the dimensions of the channels that would host this water. Keeping water in a liquid state on Mars is challenging because of its extremely low temperatures, which can plummet to -150°C (-240°F). Nonetheless, the prevalent salts present can significantly reduce the freezing point of water.

The study revealed it’s “remarkably easy” to find soil containing over 5 percent liquid water, flowing through channels with a diameter of at least 5 microns – the established criteria for a habitable environment. “These channels are roughly 10 times narrower than the thinnest human hair,” notes Sizemore. “However, it’s ample enough to shelter a microbe, with sufficient pathways for nutrient and waste movement.”

Utilizing data collected by NASA’s Phoenix lander, which touched down on Mars in 2008, these potential networks of channels seem to be common at latitudes exceeding 50 degrees. If life exists on Mars, these liquid veins represent the most accessible locations for exploration, according to Sizemore: “This type of environment allows us to dig down approximately 30 centimeters and collect samples.”

A significant challenge for these channels as habitats is the extreme cold, which may exceed the tolerance levels of most known life forms. “We must tread carefully when applying terrestrial life limits to extraterrestrial conditions, as they may not depict the boundaries for life in other environments,” cautions Bruce Jakosky from the University of Colorado Boulder. “Ultimately, based on this and similar studies, it isn’t beyond the realm of possibility that life could thrive near the Martian surface.”