Mars rovers tasked with searching for biological traces can roll over microscopic life forms without smelling anything, simply because their instruments aren’t up to the task.
A new study conducted in Earth’s oldest desert shows how current technology can’t always detect the signatures of life on our planet’s surface. Not to mention Mars.
The researchers behind the investigation argue without improving our ability to identify long-dead microbes dark matterLife on Mars will continue to elude us. Especially if the life we’re looking for existed billions of years ago when the planet was much warmer and wetter than it is today.
The Atacama Desert in Chile features an ancient delta called redstone, which contains sands and rocks rich in hematite and siltstone. Geologically, this region is very similar to parts of Mars, which is why astrobiologists often use it as a model for the Red Planet.
When researchers in Chile tested the redstone’s mineralogy using the best tools available today, they discovered some mysterious signs.
Approximately 9 percent of the genetic sequences were obtained using next generation sequencing They fall into the “unclassified” category, while the remaining 40 percent of sequences cannot be assigned to anything more specific than the highest rank, such as orders or domains.
Researchers from the Autonomous University of Chile (Universidad Autónoma de Chile) He says Their findings reveal an “unusually high degree of phylogenetic indeterminacy.”
The team has Proposal A new concept to represent this uncertainty, what they call the “dark microbiome”. This term mainly refers to microorganisms that scientists can detect through genetic sequencing without knowing exactly what are they.
“So” researchers He writesThe redstone dark microbiome may consist of new, already existing species not found anywhere else on Earth, but it may also be the case that such a dark redstone microbiome actually represents the backward community of microbial species that inhabited the redstone delta in the distant past. , for which no relatives could be found in the current sequence databases.”
Redstone samples have also been analyzed by test instruments used on or destined for Mars, showing that detecting microorganisms is much more challenging, with limited or no detection in most cases.
Last year, the Mars Perseverance rover found “strong signs” of organic matter when it passed through an ancient river delta.
In the years leading up to this, Curiosity had picked up signs of organic molecules in both sand and dry mud.
These are promising discoveries, but organic matter is not a sure sign of life. It remains unclear whether these molecules actually have biological origins.
“Our analyzes by testing instruments that are on or will be sent to Mars reveal that although minerals in redstone match those detected by ground-based instruments on the Red Planet, similarly low levels of organic matter would be difficult, if not It is impossible to detect them in Martian rocks depending on the instrument and technique used,” researchers in Chile we conclude.
“Our results underscore the importance of returning samples to Earth to definitively address whether life exists on Mars.”
For years now, NASA has been planning to retrieve its samples from Mars for a closer look. But this is easier said than done. Going to Mars and back requires a space mission to go further than ever before.
The date for this historical moment is currently set for Some time in the thirties or forties of the twentieth century. Hopefully by then our tech will be better equipped to take a proper look at what we found.
The study has been published in Nature Communications.
