Purple as the New Green: Modeling Purple Microbes as Exoplanet Biosignatures

To the point

Led by Lígia Fonseca Coelho and Lisa Kaltenegger, this work argues purple microbes could signal life on exoplanets because purple bacteria harvest infrared light and often don’t need oxygen, and they built a biosignature database, modeled Earth-like worlds with varying clouds, and grew more than 20 purple bacteria from habitats including a campus pond and Cape Cod waters with help from William Philpot and Stephen Zinder, suggesting purple could be the “new green” and guiding future telescopes like the Extremely Large Telescope and Habitable Worlds Observatory to look for a pale purple dot and follow up to confirm life.