Magnified laser from Earth could attract alien attention, MIT researcher says

An MIT study proposes that laser technology on Earth could emit a beacon strong enough to attract attention from as far as 20,000 light-years away.MIT News

Just a few days after Harvard University researchers suggested that aliens may have sent a probe into our solar system, new research out of the Massachusetts Institute of Technology suggests that we may soon be able to signal our presence to extraterrestrials by using a high-powered laser beam.

No, this isn’t a pitch for a sci-fi movie. Rather, it was the basis of a “feasibility study” conducted by MIT graduate student James Clark, which found that by using existing and imminent technology, humans could, in principle, fashion a laser and a telescope into a beacon that would send out a powerful blast of radiation showing aliens that we are, in fact, here, Clark said.

The study, published Sunday in The Astrophysical Journal, claims that if humans were to shine a 1- to 2-megawatt laser through a 30- to 45-meter telescope and point it toward space, the infrared radiation beam produced would be strong enough for other intelligent life in the universe to recognize it as distinct from that of the sun, Clark said.

This hypothetical signal from Earth would be detected by extraterrestrial space observers — if they’re out there — as they scan our section of the Milky Way.

The most likely witnesses of the beacon would be “alien astronomers” from an exoplanet orbiting Proxima Centauri, the star closest to Earth (not including the sun) at a mere 4.25 light years away, Clark said.

Other viewers might be found in TRAPPIST-1, a planetary system 39 light-years away that includes three exoplanets that scientists think could be habitable, according to a statement from MIT about Clark’s study. The laser could be visible as far as 20,000 light-years away from earth, the study estimates.

“We can’t put as much power as the sun produces into a laser — that’s just not practical — but a laser produces all of its power in one wavelength, a very narrow part of the spectrum, so the way that it’s detectable is not that it’s more powerful than the sun, but that it’s very distinct from the sun,” Clark said. “If alien astronomers were looking at the sun, the spectrum of the sun would gain a little spike in it.”

Clark’s study shows that building this magnified laser is possible and that it could serve as a signal to alien life.

That doesn’t necessarily mean it should be done, he said.

“Should we be attracting extraterrestrial attention? I established that we can, but that doesn’t mean it’s a good idea,” Clark said. “Whether it’s a good idea or not is an exercise for future work.”