In the search for life on other planets, the presence of oxygen in a planet's atmosphere is one potential sign of biological activity that might be detected by future telescopes. A new study, however, describes several scenarios in which a lifeless rocky planet around a sun-like star could evolve to have oxygen in its atmosphere. The new findings, published April 13 in AGU Advances, highlight the need for next-generation telescopes that are capable of characterizing planetary environments and searching for multiple lines of evidence for life in addition to detecting oxygen. ...