Mars was likely home to a liquid water ocean 3 billion years ago, despite the freezing temperatures on the planet's surface at the time, a report from NewScientist reveals.
Scientists have long pointed to geological evidence that Mars once had large bodies of water on its surface. In fact, in October last year, NASA's Mars Perseverance rover provided photographic evidence that its landing location, the Jezero Crater, was once a large lake.
However, evidence also suggests that Mars was also a cold planet in the distant past, with temperatures below freezing that would freeze these vast bodies of water. And yet, no evidence has been found for large formations of ancient land ice on the red planet.
Now, a team of scientists led by Frédéric Schmidt at the University of Paris-Saclay proposed a theory that would explain how a liquid ocean could have existed with surface temperatures just below freezing.
Investigating the red planet's ancient environment
The team posited that the ocean was kept just warm enough to remain liquid due to the circulation of water around the planet's surface. This circulation would have kept the water's temperature at roughly 40.1°Fahrenheit (4.5°Celcius). Schmidt and his team came to their conclusion by using a computer simulation, with parameters set to match the conditions and environment of ancient Mars. The model showed that a liquid ocean likely existed and that much of Mars's southern region was frozen.
The team said their model also highlighted how ancient life may have existed on Mars. "If we could travel in time to 3 billion years ago, we could live on this ancient Mars with just a spacesuit for oxygen," Schmidt explained. "Pressure, clouds, liquid water, ocean, rain, snow, and glaciers: all of them were very similar to Earth today. Only oxygen was missing." However, the study lead also cautions that "stronger geological evidence" from Mars is needed to back up the findings from his team's computer models.
With the Mars Perseverance rover collecting rock samples that will eventually make it back to Earth, and human missions to the red planet planned for the 2030s, we will likely soon have more evidence with which to compare such models. Hopefully, the next decade will see humanity finally prove the existence of ancient life on other planets.