Scientists Cautiously Optimistic About Potential Biosignature on Mars

No Claims of Life Yet

Scientists working with NASA’s Perseverance rover stress that they have not discovered life on Mars. However, a recently studied rock, nicknamed Cheyava Falls, could potentially contain fossilized microbial remains. The rover has drilled and stored a piece of the rock for future analysis on Earth, aiming to uncover more definitive answers.

“What we are saying is that we have a potential biosignature on Mars,” said Kathryn Stack Morgan, the mission’s deputy project scientist. A biosignature refers to structures, compositions, or textures in a rock that could hint at a biological origin.

Characteristics of Cheyava Falls

Cheyava Falls exhibits fossilized microbial remains that might have been left when the area was warm and wet billions of years ago. The region was once an ancient river delta. Scientists clarified that they did not find actual fossilized organisms. Instead, they identified potential signs of past microbial life.

Kenneth Farley, the mission’s project scientist, described Cheyava Falls as the most compelling rock they have collected so far. If the rock can be brought to Earth, it could help answer the question of whether life ever existed on Mars.

Organic Compounds and Water Evidence

Perseverance’s instruments detected organic compounds within the rock, which are essential for life as we know it. The rover also found calcium sulfate veins, indicating that flowing water once existed in the area. Liquid water is a crucial ingredient for life.

Additionally, the rover observed small off-white splotches with black rings, resembling miniature leopard spots. These black rings contain iron phosphate, which could have provided energy for microbes to live on. Similar features can be seen in Red Rock Canyon near Las Vegas, where water and organic compounds caused chemical reactions that bleached parts of the red rocks white.

Challenges in Confirming Biosignatures

Despite these intriguing findings, the Perseverance rover’s limited capabilities mean scientists cannot provide conclusive evidence about the potential biosignature. The rover’s mission includes drilling samples of interesting rocks for a future mission to return to Earth. These samples can then be studied with advanced instruments in laboratories.

However, the Mars sample return mission has faced significant delays and budget issues. NASA officials are seeking ideas from private companies to bring the rocks back sooner and at a lower cost. This will impact Perseverance’s ongoing explorations and how the samples are transferred to the return spacecraft.

Future Plans for Perseverance

Scientists have planned the next year and a half of Perseverance’s mission, which includes driving out of Jezero crater and onto its rim. The landing site at Jezero was chosen because a riverbed is thought to be the most likely place to find signs of ancient life. Despite over three years of exploration without uncovering any compelling biosignatures, the mission remains valuable for its geological findings.

Leaving the riverbed does not end the search for past life. The impact that created Jezero crater likely formed hydrothermal systems along its rim, which could have provided habitable environments for life.