Could We Find Aliens by Looking for Their Solar Panels?- Designed to reflect ultraviolet and infrared, the panels have a unique fingerprint

Researchers searching for life beyond Earth spend a lot of time thinking about what telltale signs might be detectable astronomically. Forms of unambiguous evidence for the presence of life on another world are known as biosignatures. By extension, techno signatures are indicators of activity by intelligent, civilisation-building life.

- By Lewis Dartnell

Researchers searching for life beyond Earth spend a lot of time thinking about what telltale signs might be detectable astronomically. Forms of unambiguous evidence for the presence of life on another world are known as biosignatures. By extension, techno signatures are indicators of activity by intelligent, civilisation-building life.

SETI, the Search for Extraterrestrial Intelligence, focuses on picking up signals that could be alien communication, but other approaches include observing traces of industrial air pollution on an exoplanet; observing the emission of artificial light from cities on the planet's night side; or even detecting evidence that a highly capable civilisation has constructed a shell around its star, known as a Dyson sphere, to capture its emitted energy.