NASA’s Curiosity rover, currently exploring the Gale Crater on Mars, has revealed critical insights into the planet’s ancient climate. The research reveals how Mars transformed from a potentially habitable environment, abundant with liquid water, to the cold, dry landscape we see today. The artist’s concept illustrates an early Mars, where liquid water could have existed in river and lake formations. Geological evidence suggests that ancient Mars had a denser atmosphere that could have supported significant bodies of water. However, as the planet cooled and lost its global magnetic field, the solar winds eroded much of its atmosphere, leading to its current inhospitable conditions.

Findings from the Curiosity rover

Curiosity measured the isotopic composition of carbon-rich minerals (carbonates) found in Gale Crater. David Burtt of NASA’s Goddard Space Flight Center stated, “The isotopic values ​​of these carbonates indicate extreme amounts of evaporation, suggesting that they likely formed in a climate that could have supported only transient liquid water.” This indicates that although the surface environment was not suitable for life, subterranean habitats may still exist.

The role of isotopes in understanding Mars

Isotopes, which are variants of elements that differ in mass, play a vital role in understanding the climate history of Mars. During evaporation, lighter isotopes of carbon and oxygen escape into the atmosphere, leaving behind heavier ones in carbonate rocks, which serve as climate records.

Conclusion: Implications for habitability

The study suggests two mechanisms for carbonate formation: through cycles of wet and dry conditions or in extremely salty water under icy conditions. Co-author Jennifer Stern noted that these scenarios indicate different levels of habitability on ancient Mars. These findings, supported by isotopic evidence from Curiosity’s instruments, add to our understanding of the climate evolution of Mars and its potential to support life in the past.