Blasting Messages To Exoplanets

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The two questions that persist in science and science fiction communities are:

1. How do we find out if there is life out there?

2. After we find out, how do we talk to them? 

Exoplanets might contain liquid water—the key ingredient for life as we know it. So, there may be alien life on some of these planets. But how can we discover that?  

Some Scientists think we should create a humongous laser and blast exoplanets as far as 20,000 light years away, so the aliens will notice us. Then we can use that same laser to talk to them. 

An MIT study was initiated with a strategy involving an enormous infrared laser and a telescope to enhance the force of the laser. A high-powered 1- to 2-megawatt laser focused through a massive 30 to 45-meter telescope aimed into space could blast a beam of infrared radiation strong enough to stand out from the sun’s energy. If Alien stargazers were looking at our section of the Milky Way when such a signal was sent, they’d see it, especially if they lived in nearby systems, like the area of 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 seen in any of those nearby systems then we can use the same giant laser to send a brief message created with pulses, just like Morse Code.

SETI, the government agency that scans the night sky to search for alien life, would need to run more full-sky scans and invest in infrared technology that would help identify which planets have habitable atmospheres. Then, we could use a giant telescope to amplify an infrared laser signal, so it would outshine the sun’s infrared emissions. That way smart aliens on a distant planet would see it. Then, if those aliens have their own laser we can have a back-and-forth conversation, though it would take decades or maybe centuries for each message to reach its target.

James Clark, who headed the study, analyzed lasers and telescope combinations with different wattages and sizes. He discovered that a 2-megawatt laser pointed through a 30-meter telescope, might emit a signal powerful enough to be visible to stargazers in Proxima Centauri b, 4 light-years away. Clark also found that a 1-megawatt laser, directed through a 45-meter telescope, would produce a clear signal to stargazers within the TRAPPIST-1 planetary system, a distance of 40 light-years away. It’s estimated that either example could create a signal seen from up to 20,000 light-years away.

Lasers with a power of 1 to 2 and megawatts as well as colossal telescopes are emerging technologies.  The U.S. Air Force’s Airborne laser, a defunct megawatt laser originally meant to shoot ballistic missiles out of the sky, has the required laser power. And though no observatory on earth has a 30-meter telescope right now, the 24-meter Giant Magellan Telescope and the 39-meter European Extremely Large Telescope are currently being built in Chile and are on track for completion by 2024. 

Clark also examined modern imaging techniques and discovered that while a telescope 1 meter or larger could spot such a laser, it would have to be pointed in the signal’s direction to see it. 

We need to develop infrared imaging techniques, not only so we can spot any alien laser beacons, but also to identify gases in a distant planet’s atmosphere, so we’ll know which planets potentially have alien life. 

What do you think? Do you believe? Not believe? Not sure?

Perilously yours,

Pauline