Rover with LANL camera finds evidence of 'Earth-like environment' on Mars
May 1—After almost 12 years probing Mars, the Curiosity rover is still making discoveries that have scientists, well, curious.
The rover has detected unusually large amounts of manganese in rock deposits in an ancient lakebed amid the red planet's Gale Crater, using a special high-tech camera that Los Alamos National Laboratory helped develop.
On Earth, manganese becomes enriched because of oxygen in the atmosphere, and this process is often sped up by microbes.
In contrast, oxygen is extremely low on Mars and there's still no real evidence of life in its history — and yet manganese still somehow formed in high concentrations in this one place, said Patrick Gasda, a researcher in the lab's space science program.
"That's how it happens on Earth, so it's crazy to see it on Mars," Gasda said.
The findings were published Wednesday in the Journal of Geophysical Research: Planets.
The rover collected data from chemical analyses it did at the lakebed in 2017, using the ChemCam that the lab and the French space agency CNES developed.
The research team required time to sift through the complex information and reach a consensus about what it all means, Gasda said.
Manganese forming could mean Mars at one time had a more oxygen-rich atmosphere, which in itself would make scientists wonder, "Why is that?" Gasda said.
Although the high levels of the mineral might hint at microbes at play, Gasda said he and other researchers are careful not to suggest the possibility Mars was home to even the most rudimentary life because the evidence simply hasn't been found.
Organic matter has been detected in rocks, but that's a long way from confirming microbes existed on Mars, Gasda said.
Both Curiosity and the new-generation Perseverance rover have scouted areas of the now-desolate planet where lakes, rivers and a sea covered much of the surface some 3.7 billion years ago.
The clear, geological signs of past water bodies raise the question of whether organisms thrived there at one time, given that life often springs from water.
In 2022, after the Perseverance rover's SuperCam showed the rock in the Jezero Crater is volcanic and not the sedimentary type you'd expect in a former water body, a lab scientist echoed Gasda's sentiments about how Mars might always have been a dead planet.
"From orbit and actually from the rover missions ... there are many indications that there was water present in multiple locations, perhaps hemispherical oceans at one time," researcher Sam Clegg told The New Mexican. "But whether or not microbes actually grew in that environment is still a basic question."
Gasda said a long-ago lake in the Gale Crater presumably had the minerals and other elements to help support life. But until you see real remnants of life, be it a plant, microbe or a dinosaur, you can't know, he said.
Scientists will be able to more deeply and thoroughly analyze rocks for signs of life when they are brought to Earth in what NASA is calling the Mars sample return, Gasda said.
There's much debate about how and when this mission will be carried out, he said. When it does happen, scientists will have much more sophisticated equipment to examine the rocks than what's available on the rovers, he added.
The manganese finding is a reminder Mars has much to reveal about its past; in this case, it appeared to mimic an Earthly process that requires oxygen and microorganisms the red planet lacks.
"This particular one is significant because of this, like, mystery," Gasda said. "We don't really know how it could form."
This discovery underscores the need to do much more research, including about whether Mars was ever habitable, Gasda said.
"We have rule out all of the other possibilities before we would ever talk about life" on Mars, Gasda said. "We're just pointing out this observation is weird with everything we know about Mars."
