E.T. we’re home “porch light.”
Credit: MIT


There are those paranoid about letting any starfolk know we’re here, cringing on planet Earth.

But a new MIT study suggests that existing laser technology could be fashioned to attract alien astronomers – sort of an E.T. we’re home “porch light.”

The research stems from James Clark, a graduate student in MIT’s Department of Aeronautics and Astronautics and Clark’s advisor, Associate Professor Kerri Cahoy. The “feasibility study,” appears today in The Astrophysical Journal.

On the beam

The findings suggest that if a high-powered 1- to 2-megawatt laser were focused through a massive 30- to 45-meter telescope and aimed out into space, the combination would produce a beam of infrared radiation strong enough to stand out from the Sun’s energy.

The required laser power of 1 to 2 megawatts is equivalent to that of the U.S. Air Force’s Airborne Laser, a now-defunct megawatt laser that was meant to fly aboard a military jet for the purpose of shooting ballistic missiles out of the sky.
Credit: U.S. Air Force

Such a signal could be detectable by alien astronomers performing a cursory survey of our section of the Milky Way — especially if those astronomers live in nearby systems, such as around Proxima Centauri, the nearest star to Earth, or TRAPPIST-1, a star about 40 light-years away that hosts seven exoplanets, three of which are potentially habitable.

If the signal is spotted from either of these nearby systems, the study finds, the same megawatt laser could be used to send a brief message in the form of pulses similar to Morse code.

Detectable signal

“This would be a challenging project but not an impossible one,” Clark says in a MIT press statement.

“The kinds of lasers and telescopes that are being built today can produce a detectable signal, so that an astronomer could take one look at our star and immediately see something unusual about its spectrum,” Clark adds. “I don’t know if intelligent creatures around the Sun would be their first guess, but it would certainly attract further attention.”

Clarks says such a laser beacon could be installed on the far side of the Moon. “In general, this was a feasibility study. Whether or not this is a good idea, that’s a discussion for future work.”

Note: Story adapted from Jennifer Chu/MIT News Office release.

To access the paper — “Optical Detection of Lasers with Near-term Technology at Interstellar Distances” – by James R. Clark and Kerri Cahoy, go to:


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