Mars might hold enough oxygen under its surface for life

We've long thought about the unlikely possibility of life on Mars, but it's under the planet's surface where those chances look stronger.

A new study published in Nature suggests that the salty water which subsists under Mars' surface could hold enough oxygen to support the kind of life which flourished on Earth billions of years ago.

While there are traces of ice deep under the planet's surface, the sheer scarcity of oxygen in Mars' atmosphere has diminished any belief that life could thrive on the planet. Until now.

"We discovered that brines on Mars can contain enough oxygen for microbes to breathe," NASA Jet Propulsion Laboratory (JPL) theoretical physicist Vlada Stamenković, the lead author of the paper, told AFP.

"This fully revolutionises our understanding of the potential for life on Mars, today and in the past ... We never thought that oxygen could play a role for life on Mars due to its rarity in the atmosphere, about 0.14 percent."

In 2016, the Curiosity Mars rover found high levels of manganese oxides, a discovery which points to the likelihood of the planet having more atmospheric oxygen then than it does now.

In the latest study, the researchers put together models to see how oxygen would dissolve in the brine, in temperatures which would be expected on the surface of Mars.

A first model looked at temps below freezing, while a second model estimated climate changes over the last 20 million years, and then over the next 10 million years.

They found oxygen becomes far more soluble in waters with lower temperatures and higher salt content, which means that the planet's polar regions could show the most potential for future life.

"Our results do not imply that there is life on Mars," Stamenkovic added. "But they show that the Martian habitability is affected by the potential of dissolved oxygen."