New evidence of Mars' wet and warm past discover

By Alimat Aliyeva

NASA's Curiosity rover has uncovered new evidence supporting the theory of Mars having a warmer and wetter past, Azernews reports.

The discovery of siderite, a mineral found abundantly in the rocks sampled by the rover, provides further proof that the Red Planet once had a more hospitable environment. This iron carbonate mineral was identified in sedimentary rocks drilled by the Curiosity rover in Gale Crater. Its presence is significant because it indicates that Mars once had a dense atmosphere rich in carbon dioxide, which could have caused a greenhouse effect that heated the planet enough to allow for the presence of liquid water on its surface.

The Curiosity rover, which landed on Mars in 2012, has been exploring the potential for microbial life on the planet. The discovery of siderite, along with other evidence, strengthens the hypothesis that liquid water may have once flowed across the Martian surface, potentially forming oceans, lakes, and rivers that could have supported life billions of years ago.

As on Earth and Venus, carbon dioxide is a crucial greenhouse gas that regulates the planet's climate. On Mars, its presence would have trapped heat from the Sun, making it warm enough for liquid water to exist in the past.

Until now, scientists had no direct evidence that Mars' atmosphere had once been rich in carbon dioxide. The prevailing theory has been that when Mars lacked a thick carbon dioxide-rich atmosphere, carbon was trapped in rocks as carbonate minerals through geochemical processes.

The samples collected by Curiosity, which involved drilling into rocks about 3 to 4 centimeters deep to study their chemical and mineral composition, provide solid evidence supporting this theory. The rock fragments analyzed were about the size of a passenger car, and their mineral content aligns with the idea that Mars had a more stable, warmer climate long ago.

"One of the long-standing mysteries in planetary evolution and the habitability of Mars is: If large amounts of carbon dioxide were necessary to warm the planet and maintain liquid water, why are there so few carbonate minerals on the surface of Mars?" said the research team from the University of Calgary in Canada.

It is believed that the sedimentary rocks found in Gale Crater formed around 3.5 billion years ago, when there was likely a lake in the area, before Mars’ climate underwent significant changes that made it the cold, dry world we see today.

The discovery of siderite is important not just because it indicates a warm and wet past for Mars, but also because it serves as a clue about the planet's early atmosphere. The presence of this mineral in ancient rocks shows that Mars once had the necessary conditions to support liquid water, which is essential for life as we know it.