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As the Perseverance rover traversed an past stream vale successful Mars' Jezero Crater backmost successful July 2024, it drilled into the aboveground and extracted a illustration from a unique, striped stone called Chevaya Falls.
The rover's instruments past analyzed the sample, which is called Sapphire Canyon, and surveyed the surrounding rock.
When scientists started looking into the data, they recovered 2 types of iron-rich minerals arranged connected the stone successful a distinctive, spotted pattern. Both of these minerals are associated with beingness connected Earth. One is recovered astir decomposing integrated substance connected Earth, portion the different is produced by definite microbes.
Related: Life connected Mars? NASA's Stunning Discovery Is The Best Evidence Yet
A squad of researchers determined successful a study published Sept. 10, 2025, that the illustration contains a imaginable biosignature – which could suggest the reddish satellite erstwhile hosted microbial life.
These minerals whitethorn person formed connected the stone erstwhile past microbes utilized chemic reactions to nutrient energy. But chemic reactions not related to beingness tin besides nutrient these minerals nether definite conditions.
To larn more, The Conversation US asked Amy J. Williams, an astrobiologist astatine the University of Florida, astir biosignature hunting connected Mars and what's truthful peculiar astir this Sapphire Canyon sample.
What are biosignatures?
A biosignature is any characteristic, element, molecule, substance, oregon diagnostic that serves arsenic grounds for past oregon contiguous life. It indispensable beryllium thing that cannot beryllium produced without life. Some examples see fossils, organic molecules derived from a biologic process, oregon mineral patterns that signifier lone done microbial activity.
There are six types of biosignatures that scientists whitethorn find connected Mars. (The Planetary Society, CC BY)A imaginable biosignature, which is however the Sapphire Canyon uncovering is described, is simply a substance oregon operation that mightiness person a biologic root but requires much information oregon further survey earlier scientists tin marque a decision astir the lack oregon beingness of life.
How bash scientists find whether thing could beryllium a biosignature connected Mars?
Biosignatures travel successful galore antithetic flavors – chemical, physical, oregon structural. Some are alternatively obvious, similar a dinosaur fossil connected Earth, but astir are acold much nuanced.
The hunt for past beingness connected Earth partially informs the hunt for biosignatures connected Mars. Researchers trust connected subtle clues preserved successful the stone grounds to code questions specified arsenic however agelong agone microbial beingness arose connected Earth. We hunt for that grounds successful environments specified arsenic craters and water beds with precocious preservation potential, meaning those that are apt to sphere the biosignatures.
Scientists tin apply these techniques to the hunt for beingness connected Mars. That is wherefore Perseverance was sent to Jezero Crater. In the past past, the crater hosted a river-fed lake, which connected Earth would correspond a habitable environment: 1 wherever beingness would privation to unrecorded if it ever arose.
This crater was an perfect determination to hunt for past beingness preserved successful the stone grounds connected Mars. Astrobiologists past hunt for chemical, textural, and mineral patterns that lucifer processes influenced by beingness backmost connected Earth.
What makes this illustration unsocial and interesting?
The Sapphire Canyon illustration is unsocial due to the fact that Perseverance's PIXL and SHERLOC instruments revealed distinctive textures that were dubbed "leopard spots."
These spots are concentric absorption fronts – places wherever chemic and carnal reactions hap – enriched successful the minerals vivianite, which contains robust phosphate, and greigite, which is made of robust sulfide.
Chevaya Falls, a stone successful the Martian Jezero Crater, is speckled with 'leopard spots,' which could bespeak chemic reactions that whitethorn person erstwhile supported past life. (NASA/JPL-Caltech/MSSS)On Earth, vivianite often forms successful environments with tons of decaying integrated matter, portion definite microbes that usage sulfate for vigor tin nutrient greigite. Compounds successful some these minerals are portion of a chemic process called redox gradients, which refers to a bid of gradual changes implicit carnal abstraction wherever chemicals tin oxidize (lose electrons) oregon trim (gain electrons).
One illustration is leaving your metallic motorcycle retired successful the rain. Over time, the reduced robust (Fe2+) volition suffer an electron and oxidize to rust (Fe3+). This process tin hap nonbiologically, arsenic vulnerability to h2o and oxygen thrust the chemic changes that instrumentality your caller motorcycle to a rusty motorcycle – I suggest not leaving it successful the rain.
But immoderate oxidation and simplification processes are truthful dilatory connected their ain that the lone mode they tin hap is with surviving organisms that propulsion the reactions forward. This process is however galore microbes, specified arsenic bacteria, get the vigor to live.
Because these 2 minerals successful the Sapphire Canyon illustration some hap successful redox gradients, scientists foretell that microbial life, if it was ever present, could person played a relation successful the reactions that created these mineral signatures.
Now, scientists are looking into the explanations that wouldn't necessitate beingness to signifier these features connected the sample.
Did scientists expect to find a illustration similar this?
This was a uncovering that we had hoped for. However, it was somewhat unexpected successful this peculiar location. This illustration came from immoderate of the youngest sedimentary rocks the ngo has investigated to date. An earlier prediction had assumed signs of past beingness would travel from older Martian stone formations.
Finding these features successful younger rocks widens the model of clip that Mars was perchance habitable and suggests that Mars could person been habitable aboriginal successful the planet's past than scientists antecedently thought, and older rocks mightiness besides clasp signs of beingness that are simply harder to detect.
What are the adjacent steps to archer whether the illustration indicates signs of past life, oregon whether the signature is from a nonbiological process?
The mineral associations are a imaginable fingerprint for those redox reactions that tin hap erstwhile microbes thrust the absorption guardant – but abiotic processes, specified arsenic sustained precocious temperatures, acidic conditions and binding by organic compounds, could besides explicate them.
However, the Cheyava Falls stone shows nary signs that it's been exposed to the precocious vigor oregon acidity usually required for greigite and vivianite to signifier nonbiologically.
Still, the lone definitive mode to reply this question is to instrumentality the illustration to Earth, wherever scientists tin usage precocious laboratory techniques to separate biologic from nonbiological origins.
Amy J. Williams, Assistant Professor of Geology, University of Florida
This nonfiction is republished from The Conversation nether a Creative Commons license. Read the original article.
