Get excited, but not too excited. NASA announced the discovery of a Mars rock that “possesses qualities that fit the definition of a possible indicator of ancient life.” The rock is shaped like an arrowhead and was spotted by the Perseverance rover in the Jezero Crater in July. “The rock exhibits chemical signatures and structures that could possibly have been formed by life billions of years ago when the area being explored by the rover contained running water,” NASA said in a statement on Thursday.
This isn’t an announcement of proof of ancient microbial life on Mars, but it’s a call for deeper research to better understand what the rover found. “Other explanations for the observed features are being considered by the science team, and future research steps will be required to determine whether ancient life is a valid explanation,” NASA said.
The Perseverance team nicknamed the sedimentary rock “Cheyava Falls” in honor of the tallest waterfall in the Grand Canyon. “Cheyava Falls is the most puzzling, complex and potentially important rock yet investigated by Perseverance,” said project scientist Ken Farley. The rock measures just over 3 feet at its widest. The white veins running along the rock contain calcium sulfate.
Of particular interest are bands of reddish material between the sulfate veins. Within those bands are tiny white splotches ringed with black material. NASA likens them to leopard spots. Perseverance determined the black rings have iron and phosphate. Astrobiologist David Flannery called the spots “a big surprise” and said, “On Earth, these types of features in rocks are often associated with the fossilized record of microbes living in the subsurface.”
The rover’s Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals instrument, better known as SHERLOC, analyzed the rock and found organic compounds that are sometimes referred to as the building blocks of life. However, these compounds can have nonbiological origins, so their presence alone isn’t proof of past microscopic life.
The rover also spotted small crystals of the mineral olivine, which forms from magma. It’s a puzzling feature that has left scientists contemplating the possible ways the rock might have formed. NASA posed a question: “Could the olivine and sulfate have been introduced to the rock at uninhabitably high temperatures, creating an abiotic chemical reaction that resulted in the leopard spots?” There’s no answer yet.
The rover collected a sample from Cheyava Falls on July 21 by drilling out a pencil-thick piece and storing it in a tube. It’s the 22nd core sample collected by the rover. NASA has been hoping to send an ambitious follow-up mission to Mars to pick up and return some of the Perseverance samples to Earth, but the concept has run into serious budget woes. NASA has been rethinking the mission.
The rover found Cheyava Falls along an ancient river valley called Neretva Vallis. Jezero Crater is a dry and dusty place now, but NASA has uncovered a long-ago history of water in the area. That’s what made Jezero such a prime region for exploration as Perseverance looks for signs of microbial life from the red planet’s deep past. The intriguing rock shows evidence of water interaction, another key ingredient for life as we know it.
It would change our view of the universe if Cheyava Falls contains evidence of ancient life on Mars. It would mean Earth was not alone in harboring life in our solar system. The rover is a highly advanced rolling laboratory, but it has limitations. Cheyava Falls will hold onto its secrets unless NASA figures out a way to bring it to Earth. “We have zapped that rock with lasers and X-rays and imaged it literally day and night from just about every angle imaginable,” said Farley. “Scientifically, Perseverance has nothing more to give.” This may be NASA’s most potent argument yet for funding a sample return mission.
