Why has life flourished on Earth but never taken root on Mars — even though the two planets are relatively similar?
A new discovery by NASA’s Curiosity rover may help answer that question. Researchers say Mars’ surface was shaped by ancient rivers and lakes, but its habitability was likely limited to rare and brief “oases,” while the planet remained mostly a barren desert.
The study, published Wednesday in Nature, suggests that the way Mars’ atmosphere and geology interact left it unable to sustain water — and therefore life — for long periods.
Carbonate rocks hold the key
Earlier this year, NASA’s Curiosity rover uncovered rocks rich in carbonate minerals. On Earth, carbonates (like limestone) absorb carbon dioxide from the air and lock it into rock. Volcanic eruptions eventually release that carbon back, creating a stable climate cycle that supports flowing water and life.
But Mars seems to have missed out on this balance. According to Edwin Kite, the study’s lead author and a planetary scientist at the University of Chicago, Mars has a “feeble” rate of volcanic outgassing compared to Earth. This lack of volcanic activity means carbon dioxide gets trapped in rocks without being replenished, leaving the planet cold and dry.
“Our research shows that there were blips of habitability in some times and places, but they were the exception rather than the rule,” Kite told AFP.
Brief water “oases” amid long dry spells
The research team’s models suggest that periods of liquid water on Mars were short-lived, separated by up to 100 million years of desert conditions. This cycle made it extremely difficult for any life to gain a foothold, even during the occasional “oases” of habitability.
Still, scientists don’t rule out the possibility of underground pockets of liquid water that remain hidden from view.
Kite noted that NASA’s Perseverance rover, which landed on an ancient Martian river delta in 2021, has also detected carbonates at the edges of a dried-up lake — further supporting the new findings.
What’s next for Mars exploration?
The next big step, according to researchers, is to return Martian rock samples to Earth for closer study. Both NASA and China are planning missions in the next decade to bring back pieces of Mars, which could provide the strongest evidence yet of the planet’s history — and whether life ever had a chance.
This research brings us closer to understanding why Mars, though once wet and perhaps briefly habitable, ultimately became the cold, dry desert we see today — and underscores the delicate balance that allowed life to thrive here on Earth.