Stars’ weather could amplify signs of alien life

Abstract

If you’re someone hoping aliens exist, the discovery of rocky, potentially habitable planets circling distant stars counts among the most exciting developments of the last few decades. To better understand these worlds and look for signs of life, scientists largely rely on spectroscopy to determine the chemicals in the planets’ atmospheres. New research shows that flares and other stellar weather can have serious impacts on some exoplanets’ atmospheric chemistry—and in some cases that could make evidence of life easier to spot ( Nat. Astron. 2020, DOI: 10.1038/s41550-020-01264-1 ). Stellar flares, coronal mass ejections, and proton events—activities that blast out energy and particles from stars—bombard stars’ orbiting planets with radiation that can induce chemical reactions. Earth’s magnetic field and ozone layer largely protect our atmosphere from these events, but the events can have larger effects on planets without magnetic fields . Previous work has predicted the effects of such stellar weather