(CNN) Finding potential evidence of life on Mars may be harder than expected, according to new research.
Perseverance and curiosity Each of the rovers is equipped with a suite of science instruments that can analyze rock and dust samples and gather data about the Red Planet. But instruments currently sitting on Mars, and those designed for future missions, may not be sensitive enough to detect biosignatures or signs of existing or ancient life.
To test the capabilities of these scientific instruments, researchers traveled to Chile’s Atacama Desert, the driest place on Earth and the oldest desert in the world. Arid deserts have been considered for a long time Mars analog for scientists – even more so when researchers found the desert’s Red Stone Jurassic fossil delta. The 100-million-year-old river basin resembles the Jezero Crater on Mars and its ancient river delta.
The Perseverance rover is currently exploring the crater and delta, a lake and river bed 3 billion years ago, looking for signs of ancient life and collecting samples. The Diligent collected mud and rocks It will be returned to Earth in the 2030s by NASA and the European Space Agency Mars sample return campaign.
A team of researchers examined the Red Stone site in northern Chile to see how it compares to Jezero Crater and found it to be geologically similar, with sandstone and clay and hematite – the same iron oxide that gives Mars its distinctive red color.
Mars-like conditions on Earth
The researchers collected samples from the river bank and tested them using sensitive laboratory equipment. When pushed to the edge of their detection limits, laboratory equipment analysis revealed a mix of biosignatures from extinct and living microbes. Although incredibly dry, Red Stone is close to the ocean, where mist rolls in to provide water for microbial life.
Many microbial DNA sequences come from unidentifiable “dark microbes”—the nickname given to the genetic material of previously unknown microbes. Researchers coined the term because it is synonymous dark matter – A hypothetical form of unidentified matter in the universe.
The researchers went a step further by testing four scientific instruments designed to explore the Red Planet on samples they collected from the ancient riverbed. Although highly sophisticated, the instruments were unable to detect any molecular signature—demonstrating that the instruments may not be sensitive enough to accurately detect biosignatures.
The paper was published in the journal Tuesday Natural communication.
Detecting life requires advanced instruments
Mars missions have been searching for signs of life on the Red Planet since the first Viking landers arrived on Mars in the 1970s. NASA’s subsequent rover missions were more advanced instruments They discovered simple organic moleculesBut may be made up of molecules Chemical reactions unrelated to life.
If life did exist on Mars billions of years ago, it is expected to contain only low levels of organic matter, meaning that identifying past signs of life on Mars would be incredibly difficult with current technology, the study said.
“The possibility of getting false negatives in the search for life on Mars highlights the need for more powerful instruments,” said Dr. Armando Azua-Bustos, a research scientist at the Astrobiology Center in Madrid.
The study’s findings support the goals of the Mars Sample Return Program, a multimission effort to return Martian rocks and soil to Earth, where scientists can use state-of-the-art laboratory equipment to detect clear signs of life.
“Our results emphasize the importance of returning samples to Earth to definitively determine whether life existed on Mars,” the researchers wrote in the study.
Care should be taken when evaluating the first Martian samples returned to Earth, wrote Carol Stoker, a staff planetary scientist at NASA Ames Research Center in Mountain View, California. Opinion essay with study. Stoker did not engage in research.
“Any biological activity in these samples may have occurred billions of years ago, and only a few small samples can be brought back to Earth for study,” Stoker wrote. “It remains to be seen whether unambiguous signatures of life can be found in those limited samples. We must be cautious about interpreting the absence of strong evidence of life as proof of its absence!”
One of the instruments tested will travel to Mars aboard the first European rover, Rosalind Franklin, which is expected to launch to the Red Planet by 2028.
“(It) will carry a probe with an unprecedented ability to reach depths of 2 meters (6.6 feet), analyzing sediments that are well-preserved against the harsh conditions on the Martian surface,” said study co-author Alberto G. Faren said. visiting scientist at the Center for Astrobiology in Madrid and the Department of Astronomy at Cornell University, in a statement.
“If the biosignatures we expect are better preserved at depth, those deeper samples will have greater abundance and diversity and better preservation of the biosignatures. So our instruments on the rover will have a better chance of detecting them.”
