Scientists want to build a laser that could guide an extraterrestrial civilization and bring them to Earth.
A new research paper from an MIT graduate student suggests that humanity could theoretically build an infrared laser that could be both hot and bright enough to attract the attention of intelligent civilizations, if it was aimed at nearby exoplanets. James Clark, the study’s lead author, believes it would “certainly attract attention.”
“This would be a challenging project but not an impossible one,” Clark said in a 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. I don’t know if intelligent creatures around the sun would be their first guess, but it would certainly attract further attention.”
The study, which has been published in The Astrophysical Journal, cautions that the probability of contact is low with current methods and technology, but advances in the coming years could make it possible.
“While the probability of closing a handshake with even a nearby extraterrestrial intelligence is low with current survey methodologies, advances in full-sky surveys for SETI and other purposes may reduce the mean-time-to-handshake to decades or centuries, after which these laser systems may close links at data rates of kbps–Mpbs,” the study’s abstract reads. “The next major gap to address for searching for extraterrestrial lasers is in expanding spectral searches into the infrared, where most terrestrial communication and high-power lasers are manufactured.”
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.
“If we were to successfully close a handshake and start to communicate, we could flash a message, at a data rate of about a few hundred bits per second, which would get there in just a few years,” Clark added in the statement.
Despite the excitement of building a laser shooting 20,000 light-years away, there are inherent safety issues, Clark said, including the inherent power created by the laser
(a flux density of about 800 watts of power per square meter, which is near that of the Sun) and the prospect of the beam damaging people’s vision if they look directly at the beam, even if it isn’t visible.
“If you wanted to build this thing on the far side of the moon where no one’s living or orbiting much, then that could be a safer place for it,” Clark added. “In general, this was a feasibility study. Whether or not this is a good idea, that’s a discussion for future work.”
Ultimately, Clark and the study’s co-author, Kerri Cahoy, believe that a telescopic beacon could help contact aliens if it were to help make the Sun look odd, effectively emitting a flash, causing any intelligent civilization to sit up and take notice.
“With current survey methods and instruments, it is unlikely that we would actually be lucky enough to image a beacon flash, assuming that extraterrestrials exist and are making them,” Clark noted. “However, 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 E.T. is phoning, we will detect it.”
What could go wrong?