Welcome to a special A to Z Challenge edition of Sciency Words! Sciency Words is an ongoing series here on Planet Pailly about the definitions and etymologies of science or science-related terms. In today’s post, M is for:
In a sense, SETI researchers are just sitting by the phone waiting for somebody to call. Maybe that’s the wrong way to go about it. Maybe it’s time to pick up the phone, start dialing numbers, and see who picks up.
This idea is sometimes called active SETI, but it’s more common (and according to this paper, more appropriate) to use the term METI: the messaging of extraterrestrial intelligence.
Earth has been broadcasting TV and radio signals for over a century. This has led to a common misconception that even now, aliens on some far off planet might be gathering around their equivalent of a television set, watching old episodes of Howdy Doody or The Honeymooners. Or perhaps, if the aliens live nearby, they’re currently listening to our more recent music.
But Humanity is only a Type 0 or Type I civilization, depending on which version of the Kardashev scale you’re using. Either way, our broadcasts are not actually that strong. As David Grinspoon explains in his book Earth in Human Hands:
Our television signals are diffuse and not targeted at any star system. It would take a huge antenna, much larger than anything we’ve built or planned, to pick up on them. From a radio point of view our planet is not completely hidden, but it is hardly conspicuous. This could easily change. Targeted messages sent directly toward nearby stars would cause Earth suddenly to turn on like a spotlight, becoming an obvious beacon announcing, for better or worse, “We are here!”
Of course we’ve already done this. Several times, in fact. But not with enough consistency to truly make our presence known.
The first attempt was in 1974, when Frank Drake and Carl Sagan transmitted a message from the Arecibo radio telescope in Puerto Rico, aimed at the M13 globular cluster. But according to Grinspoon, if aliens ever do pick up that signal, “[…] they might dismiss it as a momentary fluke. We would.” That’s because the Arecibo message was a quick, one-time thing. By itself, it’s hardly proof beyond a reasonable doubt that life exists on Earth.
If we really want to get somebody’s attention, we have to send a sustained, repetitive signal, kind of like those repetitive radio pulses Jocelyn Bell detected in the 60’s. We have the technology. We can make METI a reality. But should we? Some say yes, others no. After all, we have no idea who might hear our signal, or what form their response might take, and there is no guarantee that the aliens will be friendly.
METI is a discussion and a debate that maybe we all, as a species, should be part of. Perhaps we should take a vote, because in the end, we all have a stake in what might happen. And while we’re at it, there are some other issues we all, as a species, should vote on. Or at least that’s what Grinspoon says we should do in his book.
Next time on Sciency Words A to Z, we’ll go back in time and check out the oceans of Mars.