First contact

Our current technology limits us to studying the atmospheres of giant planets orbiting close to their parent stars. But NASA’s Transiting Exoplanet Survey Satellite is cataloguing a number of promising candidates for follow-up studies with the James Webb Space Telescope, which will have the capability to detect an overabundance of oxygen in the atmospheres of alien worlds. As first-contact scenarios go, it may not be that exciting. It’s likely our first evidence for life outside Earth will take the form of a wiggle in a line on a plot, telling us that living creatures have dramatically altered the equilibrium of their home planet.