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In the search for extraterrestrial life, we Earthlings naturally look for signs of water or the green, lush lifeforms that cover our planet. But the Universe is not just our mirror, and our imaginations must stretch way beyond the familiar. Last summer, a student in the MBL Microbial Diversity course was inspired to take up this challenge, leading to her new publication, " in Monthly Notices of the Royal Astronomical Society: Letters.

“During the course, I encountered so much biodiversity that the astronomy community is still missing in their models to search for extraterrestrial life,” says lead author , a postdoctoral associate working with Lisa Kaltenegger at the at Cornell University. “Most models still ignore the concept of diverse microbial communities, focusing instead on single, green photosynthetic species. As soon as I got back to Cornell, I immediately started working on this paper, bridging the fields of microbial diversity and astronomy.”

The paper explores how “purple bacteria” – some of which she collected in Woods Hole -- may cover the surface of planets that orbit M stars, the cool, reddish-looking stars that are the most abundant in the Universe. Unlike green bacteria and plants that use the pigment chlorophyll to synthesize their food in the visible light range, purple bacteria contain purple pigments that photosynthesize in the invisible, infrared light range.