Imagine surfing to your favorite science news website tomorrow to see headlines announcing the detection of a radio signal coming at us from an extraterrestrial civilization.
Impossible? Not really.
Yes, it’s true that over the past 50 years approximately 100 SETI (Search for Extraterrestrial Intelligence) programs have come up empty handed. But veteran SETI scientist Jill Tarter has pointed out that in terms of the volume of the Milky Way, we have only surveyed the equivalent volume of a Starbucks cup of coffee as compared to the volume of Earth’s oceans. The galaxy in a big place. Or, as 19th century Scottish essayist Thomas Carlyle put it, potentially a “sad spectacle, . . . for misery and folly.”
Assuming there are other technological civilizations in our galaxy, and that some subset of them attempt interstellar communication via radio beacons, then detecting a signal is only a matter of when, not if.
For example, the planned Square Kilometer Array radio telescope being built by an international consortium could detect a powerful pulsed beacon anywhere in the galaxy. But such beacons might simply be overlooked as anomalous pulsating neutron stars.
But an unequivocally artificial transmission should eventually pop up. Once the shock and awe of at last realizing we’re not alone in the universe has settled in, there will be a spirited debate over whether we should send a response to the aliens.
But who speaks for Earth?
John Billingham of the SETI Institute, and James Benford of Microwave Sciences in Lafayette, Calif., say that in anticipation of such a “Day the Earth Stood Still” moment, we need to establish an international symposium now to reach a consensus on how and if we should respond to E.T.
They would like to see a moratorium on any METI (Message to Extraterrestrial Intelligence) broadcasts until such discussions take place.
What’s been transmitted to the stars so far is pretty innocuous: musical melodies performed on the Theremin, binary bilingual Russian and English greetings, Facebook message style text files, and modern day hieroglyphics.
At first glance I think the worry about talking to aliens is melodramatic considering that their signal would probably come from hundreds or even thousands of light-years away. Like it or not, the sheer size of the galaxy imposes heavy duty roaming charges that make it implausible that extraterrestrials will ever engage in a two-way conversation with us. That is, unless the science fiction dream of faster-than-light “subspace” chatter is realized. The paradox is that you would receive an answer from E.T. before you transmitted a question.
Equally melodramatic is the authors’ concern that a broadcast from Earth might endanger our species. Astrophysicist Stephen Hawking made world headlines last year when he warned that contact with extraterrestrials would be dangerous.
Hawking cited anthropological examples where an advanced culture crushes an inferior culture. But this is horribly simplistic when applied to alien minds evolved under alien suns.
Hawking doesn’t know any more about the mindset and mores of extraterrestrial civilizations that anyone else on Earth does. It’s naïve to think that they would be bellicose or altruistic.
My best guess is that they are at least curious — or else they wouldn’t blow their science budget on building a transmitter. But curious in an aloof sort of way. This is as H.G. Wells described the Martians in his 1898 classic “The War of the Worlds,” as possessing minds that are “vast, cool, and unsympathetic.”
Finally, I would argue that any number of curious civilization already know we are here by observing Earth passing in front of the sun, just as NASA’s Kepler space observatory is now doing in search of Earth clones across the galaxy.
Alien astronomers who are not much more technologically advanced than us may have already spectroscopically sniffed Earth’s atmosphere and found that it screams of a planet covered with life — especially methane polluting cows.
More advanced alien observations might measure the glow of our city lights on the nighttime side of our planet. And, monstrous radio antenna arrays the size of the city of Chicago might have already picked up the faint whisper of TV, radio and radar signals leaking off of our planet.
Bear in mind that this latter experiment can only work to a range of several dozen light years — the length of time our civilization has had telecommunications. And, the leak off signals get so weak and jumbled they are quickly lost in galactic radio noise. It would be like trying to hear the sound of a penny dropped inside a bustling airport terminal.
Finally, if E.T. has the same worries that Billingham, Benford, and Hawking have, then maybe nobody’s transmitting and everyone’s only listening.
That said, one text message now headed for the stars reads:
“You are cordially invited to an interplanetary barbeque 6:00 p.m. 4, October 2452 at my place. BYO beer and meat. RSVP.”
Image credits: SPDO/TDP/DRAO/Swinburne Astronomy, SETI Institute