In 1950, during a lunchtime conversation with colleagues at the Los Alamos National Laboratory, famed physicist Enrico Fermi asked the question that launched a hundred (or more) proposed resolutions. “Where is Everybody?” In short, given the age of the Universe (13.8 billion years), the fact that the Solar System has only existed for the past 4.5 billion years, and the fact that the ingredients for life are everywhere in abundance, why haven’t we found evidence of extraterrestrial intelligence by now? This came to be the basis of Fermi’s Paradox, which remains unresolved to this day.
Interest in Fermi’s question has been piqued in recent years thanks to the sheer number of “potentially habitable” exoplanets discovered in distant star systems. Despite that, all attempts to find signs of technological activity (“technosignatures”) have come up empty. In a recent study, a team of astrobiologists considered the possible resolutions and concluded that only two possibilities exist. Either extraterrestrial civilizations (ETCs) are incredibly rare (or non-existent), or they are deliberately avoiding contact with us (aka. the “Zoo Hypothesis“).
E.T. managed to call home with a Speak and Spell, buzzsaw blade, and an umbrella. The reality of interstellar communication is a bit more complicated. Space is really, really big. The power needed to transmit a signal across the void is huge. However, rather than using super high power transmitters, recent research by Stephen Kerby and Jason T. Wright shows that we could make use of a natural signal gain boost built into solar systems – the gravitational lensing of a solar system’s star. Networking a series of stars as nodes could get signals across vast tracts of the Milky Way. And we may be able to detect if our Sun is already part of an alien galactic communication network.