A Giant Space Laser on Earth Could Blast Messages at Alien Planets

And hey, it might work within “decades to centuries!”

Phone Home

Scientists have a new idea to contact alien civilizations: build a huge laser and start blasting exoplanets with messages.

We could build such a laser, according to research by MIT scientists published Monday in The Astrophysical Journal, with technology that either exists today or requires just minor developments.

Death Star

The laser is more of a homing beacon than a death ray. A one or two-megawatt laser, beamed out through a 30 to 45-meter telescope, would be powerful enough to reach planets as far as 20,000 light years away. For reference, the star nearest our sun is Proxima Centauri, which is just over four light years from us.

If any planet hit with our laser that happens, by some infinitesimally small chance, to host extraterrestrial life that had developed advanced technology, its occupants would be able to look back at Earth and see signs of life.

Waiting Game

The scientists behind this research are counting on SETI, the government agency responsible for scanning the night sky for alien life, to complete more full-sky scans and invest in the infrared technology that could help identify which distant planets likely have habitable atmospheres.

With those advances and if there are aliens out where with a laser of their own — that’s a big "if" — the researchers argue that we could have a back-and-forth conversation over decades or centuries, with each message taking many years to reach its target.

READ MORE: E.T., we’re home [MIT News]

More on the search for alien life: Scientists want Your Help Crafting a Message to Aliens