Pew! Pew! Pew! Powerful Laser Beacon Could Show Aliens Earth Is Inhabited

If any intelligent aliens share our cosmic neighborhood, we may be able to get their attention using a powerful laser beacon.

A 1- or 2-megawatt laser beamed through a 100- to 150-foot-wide (30 to 45 meters) telescope here on Earth could create a signal detectable by alien astronomers up to 20,000 light-years away, a new study suggests.

“This would be a challenging project but not an impossible one,” lead author James Clark, a graduate student in the Massachusetts Institute of Technology’s (MIT) Department of Aeronautics and Astronautics, said in a statement. [13 Ways to Hunt Intelligent Aliens]

“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 added.

For example, three different telescopes in the roughly required size range are scheduled to come online in the early to mid-2020s — the Giant Magellan Telescope, the European Extremely Large Telescope and the Thirty Meter Telescope (TMT). The first two scopes are being built in the Chilean Andes, whereas TMT will observe the heavens from the Hawaiian peak Mauna Kea.

And the U.S. Air Force worked to develop a megawatt-class laser for the now-defunct Airborne Laser project, which was designed to knock out missiles midflight.