Mars was once habitable and more Earth-like, NASA's Curiosity rover finds major clues

Curiosity rover finds carbon clues that hint at ancient Martian life. (Image: NASA)

NASA's Curiosity rover made an intriguing discovery while gently climbing Mount Sharp that may provide hints about prehistoric life on Mars. Large carbon reserves that were trapped inside carbonate minerals were discovered by the robot, suggesting that Mars was once warmer and perhaps habitable.

Indications from the interplay of carbon and water

When carbon dioxide combines with rock and water, carbonate minerals are created. This procedure serves as a journal of previous environmental circumstances. Even while orbiters, other rovers, and even meteorites have previously observed these minerals on Mars, Curiosity's new data offers a more thorough understanding.

Lead researcher Ben Tutolo from the University of Calgary said these findings support theories that Mars once had the right conditions for life.

Dry conditions reveal Mars’ changing climate

The minerals likely formed under dry conditions, triggered by water-rock reactions followed by evaporation. Scientists believe this happened when Mars still had a thick carbon dioxide-rich atmosphere that could support surface water. As that atmosphere began to thin, carbon dioxide started turning into stone.

Among the key minerals detected was siderite—an iron-rich carbonate—making up between five and ten per cent of the rock. These were found with salts that dissolve easily in water, suggesting past water activity. Tutolo said the shift from carbon dioxide gas to solid minerals likely cooled Mars, making it less habitable over time.

A hint at a lost carbon cycle

What makes the discovery even more striking is the presence of iron oxyhydroxides in the same location. These minerals hint at a possible carbon cycle—similar to Earth’s—where carbon might have moved back and forth between the planet’s rocks and atmosphere. Using both Curiosity’s close-up data and orbital maps, scientists now estimate these layers could have stored up to 36 millibars of atmospheric carbon dioxide. That would be sufficient to have a significant effect on the Martian climate.

A stride towards the past of Mars

This finding provides another crucial hint, even though it does not prove that there was once life on Mars. It demonstrates that the earth formerly had a dynamic climate and all the necessary components to support human habitation. With every fresh layer that Curiosity uncovers, Mars seems a bit more familiar to scientists.