NASA\u2019s Perseverance rover on Mars<\/p>\n
NASA\/JPL-Caltech<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
Has NASA found life on Mars?<\/h3>\n
In a word, no. But last year, NASA\u2019s Perseverance rover found signs in an ancient rock that could point to life having existed on the Red Planet billions of years ago. And now we have more evidence in the form of small nodules of unusual minerals in several clay-rich rocks that could have a biological origin.<\/p>\n
As exciting as the discoveries are, we need to proceed with caution: astrobiologists have a seven-step scale called the Confidence of Life Detection that puts a hard number on the quality of evidence. Even with the previous discovery and today\u2019s announcement combined, we remain on step one.<\/p>\n
What has NASA actually found?<\/h3>\n
Last year, Perseverance was exploring a lake bed called Bright Angel in Mars\u2019s Jezero crater when it came across a rock with unusual markings called \u201cleopard spots\u201d and \u201cpoppy seeds\u201d. On Earth, these markings are considered to be telltale signs of ancient microbial activity. Leopard spots are millimetre-sized dark blots with a circular rim, while poppy seeds are even smaller dark blotches.<\/p>\n
Both types of marking are found within the rock, which has been named Cheyava Falls after a waterfall in the Grand Canyon. And both types are sandwiched between white reams of calcium sulphate \u2013 a mineral that typically forms in the presence of water, which is another prerequisite for life.<\/p>\n
Today, NASA has announced we have further intriguing discoveries: clay-rich rock samples discovered at two sites \u2013 one called Sapphire Canyon, found in Bright Angel again, and another called Masonic Temple \u2013 that have tiny, green-toned specks of chemically-reduced iron phosphate and iron sulphide minerals.<\/p>\n
<\/p>\n A map showing Perseverance\u2019s path on Mars<\/p>\n NASA\/JPL-Caltech\/University of Arizona<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n On Earth, we know that both leopard spots and poppy seeds can be linked to microbial life: the reduction and oxidisation (redox) reactions that generate energy for such life forms leave coloured deposits of iron and sulphur in \u201creduced form\u201d, meaning they have gained electrons.<\/p>\n The marks in Cheyava Falls could have been caused by microbes or by another reaction that takes place only at high temperatures and isn\u2019t linked to the presence of life. But Perseverance\u2019s onboard instruments were used earlier this year to work out the chemical composition of the marks, showing that they do contain minerals in a reduced form. This suggests that the biological explanation is more likely.<\/p>\n Now, on top of that, we have these new rocks. The green flecks of chemically reduced material could, just like the previous sample, indicate the presence of life. And even more excitingly, their distribution is uneven and directly related to the concentration of organic compounds \u2013 something that certainly adds weight to the idea that they were created by living organisms.<\/p>\n Joel Hurowitz at Stony Brook University in New York and his colleagues write in a paper on the new analysis, published today in the journal Nature<\/em>, that \u201cthe Bright Angel formation contains textures, chemical and mineral characteristics, and organic signatures that warrant consideration as \u2018potential biosignatures\u2019.\u201d But, crucially, they haven\u2019t proved that living organisms were present on Mars.<\/p>\n We have all but exhausted our options for analysing Cheyava Falls and the new samples on the surface of Mars. What we really need to do is bring them back to Earth for a closer look.<\/p>\n Perseverance is designed to store interesting samples and hand them over to a future mission that will physically bring them back to Earth, but these plans have been hit by a series of setbacks in the past year or so. US President Donald Trump\u2019s proposal to slash NASA\u2019s budget is likely to mean that the Mars Sample Return mission is abandoned and any samples collected so far remain on the surface of the Red Planet, with no further analysis possible.<\/p>\n Team member Sanjeev Gupta at Imperial College London says the new discovery will add to the case for funding a sample-return mission, something NASA is very keen on. <\/span>\u201cThis is the first time [we\u2019ve seen] something that says, \u2018Oh, this could be formed due to biological processes\u2019 \u2013 and that\u2019s why the excitement is there. This is a sample we need to return,\u201d he says.<\/p>\n \n ![\"\"](\"https:\/\/images.newscientist.com\/wp-content\/uploads\/2025\/09\/10141904\/SEI_265483025.jpg\")
<\/div>What makes these related to life?<\/h3>\n
How could we confirm the results?<\/h3>\n