Context The argument was made in a preprint study that had not been peer-reviewed in the May 2021 issue of the journal Advances in Microbiology. In it, researchers claimed that NASA rovers and Mars orbiters collected visual evidence of fungi on Mars — a claim that has been widely contested by the broader scientific community. Origin In early May 2021, several authors of a preprint study published in the scientific journal Advances in Microbiology argued that photographs collected by NASA rovers and Mars orbiters showed evidence of what they believed could prove that fungi were found growing on the red planet. Soon after, headlines and social media chatter sprouted up, claiming that science had found mushrooms on Mars.