NASA’s rovers on Mars may have been rolling over microscopic life forms without even knowing it, as current technology may not be able to spot the signatures of life on the red planet. This is according to a new study conducted in Earth’s oldest desert, the Atacama Desert in Chile. Researchers from the Autonomous University of Chile argue that without improving our ability to identify long-dead ‘microbial dark matter’, life on Mars will continue to elude us.
The team tested the Red Stone’s mineralogy with the best instruments available today, uncovering some mysterious signs. Nearly 9 percent of the genetic sequences obtained using Next Generation Sequencing fell into the ‘unclassified’ category, while 40 percent of the remaining sequences could not be assigned to anything more specific than the highest of taxa, such as orders or domains.
The researchers have proposed a new concept to represent that uncertainty, what they call a “dark microbiome”. This term essentially refers to microorganisms that scientists can detect via genetic sequencing without knowing exactly what they are.
The Red Stone samples were also analyzed by testbed instruments used on Mars or destined for Mars, showing detection of microorganisms to be far more challenging, with limited or non-detection in most cases. Last year, the Perseverance rover on Mars found ‘strong signs’ of organic matter when rolling through an ancient river delta, while the Curiosity rover picked up signs of organic molecules in both sand and dried-up mud.
The study concluded that although the mineralogy of Red Stone matches that detected by ground-based instruments on the red planet, similarly low levels of organics will be hard, if not impossible to detect in Martian rocks depending on the instrument and technique used.
NASA has been planning to retrieve samples from Mars to take a closer look, but that’s easier said than done. Going to Mars and back requires a space mission to go further than ever before, with the date for this historic moment currently set for some time in the 2030s or 2040s. Hopefully by then our technology will be better equipped to take a proper look at what we have found.
