What can the climate history of Mars teach scientists about whether the Red Planet once had the ingredients for life as we know it? This is what a recent study published in Nature hopes to address as a team of researchers from the United States and Canada investigated the geological, atmospheric, and surface processes that might have played a role in Mars losing its ability to host life on its surface. This study has the potential to help scientists put constraints on when Mars could have had life and where to look for it.
For the study, the researchers developed a model that discussed how solar radiation, liquid water, carbonate formation with rocks, atmospheric pressure, and carbon dioxide all worked in tandem to determine whether the surface of Mars could sustain life as we know it. In the end, they found that while increased solar radiation resulted in liquid water existing on the surface, this also led to carbonate formation that absorbed atmospheric carbon dioxide, ultimately limiting the amount of liquid water that existed. Essentially, a negative feedback loop was created. The researchers note Mars going to several cycles of wetness and dryness worsened this feedback, resulting in the desert planet we see today.
“For years, we’ve had this huge unanswered question for why Earth has managed to keep its habitability while Mars lost it,” said Dr. Edwin Kite, who is an associate professor of geophysical sciences at the University of Chicago and lead author of the study. “Our models suggest that periods of habitability on Mars have been the exception, rather than the rule, and that Mars generally self-regulates as a desert planet.”
Carbonate rocks were the limiting factor in solving this conundrum, but NASA’s Curiosity rover discovered some carbonate rocks earlier this year, which helped scientists unlock a unique geological mystery regarding the climate history of Mars.
Image of Mt. Sharp on Mars captured by NASA’s Curiosity rover. (Credit: NASA/JPL-Caltech/MSSS)
What new discoveries about Mars’ climate history will researchers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Sources: Nature, EurekAlert!