Exoplanets were first confirmed in 1992. Before that, it was easy to simply mock the search for the flying saucers and the little green men. After that, the obvious question became: If planets, why not habitable planets? If inhabited, why not by intelligent life forms? It was the naysayers who had more to prove.
More recently, astrobiologists looking for signals from intelligent extraterrestrials (technosignatures) have started to doubt that the old standby, radio, is the best choice, as science writer Corey S. Powell reports,
‘I was never a big fan of what might be called “beacon SETI”,’ the astrophysicist Adam Frank from the University of Rochester tells me. ‘The idea is that you’re waiting for somebody to send you a message with radio, but I thought, maybe nobody wants to do that.’ Frank is one of the leading researchers embracing a different approach, one that focuses on the hunt for ‘technosignatures’: evidence of any kind of alien technology that modifies its environment in detectable ways.
Corey S Powell, “The search for alien tech” at Aeon (October 25, 2021)
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