The search for extraterrestrial life has focused mostly on exoplanets like Kepler-186f, shown here, which circle M-class stars in a “habitable zone” where water may exist. | NASA Ames/SETI Institute/JPL-Caltech

Here’s Another Method for Identifying Life on Other Planets

Boston University astronomers suggest searching for charged oxygen in the ionospheres of exoplanets as an alternative method for finding extraterrestrial life.