On Mars, a robotic rover called Perseverance is searching for life from the dawn of time. Scientists, though, are looking for life signs in even stranger places, from clouds on Venus and methane lakes on Titan, to the alien atmospheres of worlds circling distant stars. They are scanning for alien radio signals, seeking signs of industrial pollution on faraway exoplanets and scrutinizing puzzling interstellar objects that have intercepted our solar system.

The expanding quest for clues to life beyond Earth—and for signs of extraterrestrial intelligence—is edging into the mainstream of astronomy and planetary exploration. In addition to NASA’s Mars rover missions now under way, dozens of research teams are searching for biosignatures of early microbial life, while the search for plausible evidence of alien civilizations is gaining respectability.

Indeed, for the first time in a generation, the National Aeronautics and Space Administration is supporting efforts to seek signs of advanced civilizations elsewhere in the cosmos, researchers say. If life does exist beyond Earth—be it primitive or advanced—scientists may find a trace of it soon.