Published: Fri, November 09, 2018
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A Powerful Laser Beam Might Help Us Communicate With Extraterrestrials

A Powerful Laser Beam Might Help Us Communicate With Extraterrestrials

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.

That may produce a light strong enough to stand out from energy produced by the sun.

According to the scientists, the laser beam would be observable from nearby systems, such as those in the vicinity of Proxima Centauri, the closest star to Earth, or TRAPPIST-1, a celestial body at about 40 light-years away that houses seven exoplanets with three of which could be habitable.

"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 said. The laser could be visible as far as 20,000 light-years away from earth, the study estimates.

The researchers hope that the study will pave the way to the creation of infrared imaging techniques that could spot laser beacons in space.

Of course several messages intended for potential aliens (and countless not intended for them) have been beamed into space since the advent of broadcasting technology, majority encoded in radio waves, but none have been sent using super high-powered lasers.

The research suggests that a laser, 1 to 2 megawatts in strength and coming from a telescope at least 100 feet in length, aimed into space, could get the attention of civilizations as far as 20,000 light years from Earth. For instance, Clark calculated that 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 goal of shooting ballistic missiles out of the sky.

Because much of the resistance from the scientific community about ideas like these involve skepticism regarding feasibility, Clark and his team set out the explore ways in which current technology can be combined to facilitate communication.

He started with a simple conceptual design involving a large infrared laser and a telescope through which to further focus the laser's intensity. The 30-meter telescope would be much larger than any we now have as the trend is toward building multiple smaller observatories.

Potential issues with this plan include that despite that the IR beam is invisible, it would damage people's vision if they looked directly at the beam.

It should be possible to build one, though. There is legitimate concern that Earth's resources could be too tempting to resist, and that we might invite our own extinction by luring extraterrestrials to our neck of the woods. "However", he added, "as the infrared spectra of exoplanets are studied for traces of gases that indicate the viability of life, and as full-sky surveys attain greater coverage and become more rapid, we can be more certain that, if phoning, we will detect it".

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