Pollution could be used to detect life on exoplanets

"CFCs are a very interesting idea to look for advanced civilisations," agrees Lisa Kaltenegger of Harvard University. But an exceptionally sensitive telescope would be needed to pick them up - more sensitive even than NASA's Terrestrial Planet Finder and the European Space Agency's Darwin mission, the most ambitious space telescopes now being planned. Kaltenegger says it may be feasible "in the far future with a flotilla of infrared telescopes in space".