EARTHSKY // BLOGS // SPACE EarthSky OCT 18, 2012

City lights could reveal E.T. civilization

Researchers suggest the bright lights of cities, which are clearly visible on a planet even from space, have the potential to reveal the existence of alien life on other planets.

In the search for extraterrestrial intelligence, astronomers have hunted for radio signals and ultra-short laser pulses. But someday – according to Avi Loeb of Harvard-Smithsonian Center for Astrophysics and Edwin Turner of Princeton University – we might want to look for city lights.

They point out that, as our technology has moved from radio and TV broadcasts to cable and fiber optics, we have become less detectable to aliens. If the same is true of extraterrestrial civilizations, then artificial lights might be the best way to spot them from afar.

Loeb and Turner calculate that today’s best telescopes ought to be able to see lights like those of Earth’s biggest city – Tokyo – at the distance of our solar system’s own Kuiper Belt – the region occupied by Pluto, Eris, and thousands of smaller icy bodies.

In other words, if there were any cities on the edge of our solar system, we ought to be able to see them now. It’s doubtful there are cities on, say, Pluto. And all the stars – even the nearest ones – are no closer than 10,000 times Pluto’s distance from our sun. So we don’t have telescopes that could see city lights on planets surrounding those distant stars.

Read more: City lights could reveal E.T. civilization | Space | EarthSky.

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