NASA rover reveals mars’ ancient climate: extreme evaporation process found

NASA has revealed new clues about Mars' past: carbonate discoveries suggest an ancient climate favorable to a possible underground biosphere, despite extreme conditions

While Mars is an inhospitable, cold world today, NASA persists in its pursuit of signs that might answer whether the Red Planet was once hospitable to life. Based on isotopic compositions of carbonates in Gale Crater, NASA scientists operating the Curiosity rover have unveiled key information related to Mars’ old climate. As NASA researcher David Burtt explained:

The isotopic composition of the carbonates attests to an extreme process of evaporation. Probably, the minerals have formed in a climate able to support only temporary liquid water.

The findings, reported in the Proceedings of the National Academy of Sciences, reveal a far more complicated Martian climate than had been theorized. Burtt said the samples don’t point to a habitable surface environment but neither do they rule out the possibility of an underground biosphere or surface life that pre-dated the carbonate formations.

Isotopic analysis: insights into Mars’ ancient ambiance

Isotopes are forms of an element that differ in atomic mass. On Mars these evaporative processes left behind heavier isotopes of carbon and oxygen in the carbonates, giving “climate records” that tell about conditions at the time, including temperature, acidity and atmospheric composition.

Two theories on carbonate formation on Mars

Two major scenarios are considered for the possible ways carbonates could have formed in this study. First, that which is coupled with cycles of wet and dry phases within Gale Crater; and second, highly saline water under cryogenic conditions. Co-researcher Jennifer Stern explained how wet-dry cycles might have seesawed between more and less hospitable conditions while the cryogenic temperatures would lower any life-supporting possibilities. The majority of the water is locked up in ice under these cold, saline conditions, making the water not support life well.

These ancient Martian climate scenarios had been speculated earlier, too, but this is the first confirmation through direct isotopic evidence. The levels of heavy isotopes in Martian carbonates are notably higher than on Earth, which further suggests that Mars suffered from an intense evaporation never seen before.

Advanced tools on curiosity unlock climate clues

Those findings were extracted from Martian geology, while applying some of the most valuable tools aboard Curiosity: SAM (Sample Analysis at Mars) and TLS (Tunable Laser Spectrometer). The SAM instrument heats samples up to nearly 1,650 degrees Fahrenheit, while TLS analyzes the resulting gases. Assembled by NASA’s Goddard Space Flight Center, those instruments conduct a very detailed analysis of samples that lock vital keys to crucial facts about Mars’ distant past.

Fonte: NASA