There Could Be Life on Mars. Our Rovers Might Just Be Too Weak to Find It.
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Tech on the Mars rovers might be missing signs of life.
In samples from a Mars-like region of the Atacama Desert, researchers found evidence of a "dark microbiome" that the rovers likely wouldn't be able to detect.
This emphasizes the importance of bringing samples home from Mars so we can analyze them in the highest level of detail.
Researchers recently put our Mars rovers to the test by comparing their ability to detect signs of life to high-tech Earth-bound methods. Unfortunately, they fell short.
A team lead by scientists from the Spanish Astrobiology Center in Madrid took soil samples from the Red Stone region of the Atacama Desert—an area known for being about as close as you can get to the surface of Mars without leaving Earth.
The samples, when tested using the ultra-sensitive Earth-bound methods, were shown to contain about one microgram of DNA per gram of soil. As far as they can tell, that DNA came from two species of fungi, 19 species of bacteria, and what the researchers are calling the “dark microbiome.”
As dramatic as it may sound, the dark microbiome is just the name for microorganisms whose DNA we have collected, but can’t match to any known genetic code. That means it might come from completely unknown species, or from species that died out thousands of years ago.
Wherever that DNA comes from, we know it’s there, as researchers can detect it in the soil of Red Stone using high-tech equipment. But when the same soil samples were analyzed with instruments that are comparable to those on various Mars rovers, that dark microbiome appeared to either barely exists, or not exist at all. Even a life-detection instrument 10 times as sensitive as one used on Curiosity could barely spot anything in the sample.
So, even if some of our most advanced Martian sensors analyzed a soil sample to the best of their abilities, they might miss signs of life completely.
But while that’s certainly a bummer, it’s not the nail in the coffin in our search for life on Mars. Rather, the opposite—it shows us that it might be a good idea to double-check places we may have ruled out as homes for life on the red planet.
And on top of that, the results of this study further emphasize the importance of bringing samples back home to Earth to test. After all, even though the Mars rover analogues couldn’t detect signatures of life in the samples, the Earth-bound instruments could. If we can get pieces of Mars back to Earth, we have a much better chance at spotting anything that’s there to spot.
So, it’s an especially good thing that a sample return mission is already in progress. The Perseverance rover has collected 17 samples to eventually be sent back to Earth, and last month, it dropped the last of 10 tubes that make up the backup payload. These samples will eventually be scooped up as part of the Mars Sample Return campaign and brought back to Earth so we can analyze them as closely as possible.
We’ve got a while before we get those samples back—the timeline right now basically consists of “before 2030”— but when we do get them back, it seems like we’ll be able to draw a whole wealth of information from what we recover.
Maybe that will include signs of life we missed.
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