NASA’s Curiosity rover discovers clues to Mars’ Earth-like past

NASA's Curiosity rover continues to search for signs that Mars' Gale Crater conditions could support microbial life. Credit: NASA/JPL-Caltech/MSSS

Scientists using NASA’s Curiosity rover have made a significant discovery on Mars that suggests the planet might once have had conditions similar to Earth.

This discovery involves unusually high levels of manganese in the lakebed rocks within Gale Crater, indicating that these sediments could have formed in an environment much like rivers, deltas, or lake shores found on Earth.

The findings, detailed in the Journal of Geophysical Research: Planets, open new perspectives on Mars’ ancient atmosphere and its capability to support life.

Patrick Gasda from Los Alamos National Laboratory, the lead author of the study, explained the significance of finding manganese oxide in such high concentrations.

On Earth, manganese deposits are common because they are produced by the high levels of oxygen in our atmosphere—oxygen that photosynthetic life forms release.

Microbes also play a crucial role by speeding up the manganese oxidation reactions.

However, on Mars, the conditions are very different as there is no evidence of life and it is unclear how oxygen could have been produced in the ancient Martian atmosphere.

This makes the presence of manganese oxide on Mars a puzzling and intriguing find.

The ChemCam instrument on the Curiosity rover, developed by Los Alamos National Laboratory and the French space agency CNES, was instrumental in this discovery.

ChemCam uses a laser to zap rocks and create a plasma, then analyzes the light from the plasma to determine the chemical elements in the rocks.

Curiosity’s observations revealed that the manganese-rich rocks are a mix of sands, silts, and muds, typical of sedimentary rocks formed in water environments.

The sandy rocks, being more porous, likely allowed groundwater to pass through more easily—potentially leading to the enrichment of manganese through interactions with groundwater at the edge of a lake or delta.

On Earth, the presence of oxygen and microbes facilitates the accumulation of manganese.

The discovery of similar processes on ancient Mars suggests that the planet might once have had some form of atmospheric oxygen or other oxidizing conditions, even though the exact mechanisms remain unknown.

This could also imply that if microbial life ever existed on Mars, these manganese deposits would have been a valuable energy source.

Nina Lanza, the principal investigator for the ChemCam instrument, highlighted the significance of these findings.

She pointed out that the ancient lake environment in Gale Crater mirrors the conditions of Earth’s shallow lake shores, suggesting a potentially habitable environment on Mars in the past.

This discovery not only deepens our understanding of Mars’ geological history but also reinforces the idea that Mars might once have had conditions suitable for life.

Source: Los Alamos National Laboratory.