by Shane L. Larson
We live in an age of global communication, where the world is tied together electronically in ways that could not have been imagined twenty years ago. Today, you are linked to the world through your smartphone and laptop. The global village is hung on an intricate web of cellular networks and wi-fi hotspots, allowing you to be in constant communication with millions of strangers. In a world where tweeting your every move and Facebooking random snapshots of your life are often decried as technological monsters that supplant deep, meaningful relations, it is easy to forget that the growth of wireless connectivity empowers you to find and be exposed to diverse new ideas, awesome spectacles of nature and civilization, and amazing works of art.
The other day I stumbled on one such awesome spectacle: a fantastic YouTube video of Eric Clapton and Chuck Berry singing “Wee Wee Hours” (http://www.youtube.com/watch?v=mhNjQBsBPLY). As a general rule, I avoid reading comments online for anything. The signal to noise ratio on the web is very low. But I happened to notice that an astute commenter had asked, “Why isn’t this video on the space shuttle telling aliens how awesome we are?”
I understand the sentiment; this is awesome stuff. But as it turns out, we are beaming this spectacle into deep space for any unsuspecting extraterrestrial intelligence to stumble upon and realize how awesome we are. Since the invention of radio, the growth in broadband electromagnetic communication on Earth has progressed as fast as we could build transmitter towers and sell radio and television receivers to a world population enamoured with gadgets. Radio and television broadcasts are omnidirectional — the signals flood out on the airwaves in all directions so everyone in all directions can catch the broadcast. This means that UP is just as probable as sideways, and our television and radio signals are streaming into outer space, a bright electromagnetic cacophony of modern entertainment that screams to the Cosmos “Hey! We’re down here! There’s (intelligent?) life down here!” So Chuck and Eric are currently blasting their way out into the Cosmos; that performance was recorded in 1987, so the most distant point in the Cosmos that could be aware of this awesomeness is some 25 lightyears away.
As it turns out, Chuck is also rocketing out into space in other ways. Voyager 1 and 2 both carried with them a Golden Record (http://voyager.jpl.nasa.gov/spacecraft/goldenrec.html) containing instructions on how to play the record, a map to find Earth, 116 images of life on Earth, audio greetings in 55 languages, and 90 minutes of music from the planet Earth, including “Johnny B. Goode” by Chuck Berry. A single handwritten sentence is etched on each record, reading “To the makers of music — all worlds, all times.”
So in some sense, Chuck Berry is plausibly our emissary to the first extraterrestrial intelligence we will encounter. In the case of our expanding sphere of radio noise, he might be an unintentional emissary. By contrast, the Voyager record is a highly intentional attempt to communicate with life beyond the Earth. In many ways, the Voyager record embodies an almost unfathomable optimism about the chances of the record ever being found by anyone. Ignoring the sheer vastness of the empty dark between the stars that Voyager 1 and 2 are plummeting into, what are the chances of there being someone out there to find them?
There is a very famous problem about extraterrestrials in the scientific community called the Fermi Paradox. The way the Paradox was first described to me was poetic and majestic. Enrico Fermi was strolling with friends through a starlit meadow one evening, hands plunged deep in his pockets and his feet shuffling through the burgeoning spring grass as he gazed skyward at the arch of stars. He stopped, and with the casual aplomb that scientists are masters of says, “Why aren’t they here?”
Fermi’s point was that the galaxy is vast. If life is common and plentiful, humans almost certainly are not the first lifeforms to arrive on the scene. That means we should have been visited by extraterrestrial beings already, or perhaps more to the point, we should have received their radio broadcasts and their blues records! Because we have not had such encounters, and because we have not received such signals, Fermi concluded that life is not plentiful in the galaxy, and in all likelihood, we are alone.
There have since been many arguments for and against Fermi’s conclusion, which brings me back to where we started. I watched this Chuck Berry and Eric Clapton video on my smartphone, connected to a low-power cellular network. In today’s world, it is extremely common to carry in my pocket entertainment that was traditionally broadcast via television and radio. We stream music and news over the network through CNN and services like iTunes and Pandora. The age of massive radio signals that can reach the far sides of the Earth while simultaneously flooding out into space is being supplanted by the wireless grid. The sphere of loud radio noise expanding away from Earth is beginning to taper off, and it is not beyond the boundary of possibilities that it may fade all together. It is not unreasonable to imagine that in my and your lifetimes, Earth will become radio quiet, undetectable by intelligences other than our own. By a similar token, maybe the aliens are out there, but they’ve gone radio quiet and beings from a distant blue world will never hear them either.
It is plausible that civilizations are only radio-bright for short periods of time until technology improves to the point that personal communication becomes portable and distributed in a planet-girdling web of fibers and low-power radio links. If so, then we may not be alone in the Cosmos. It may be that there are other civilizations, but they too are absorbed by wi-fi hotspots and alien cyber-cafes, looking forever inward and connected only to their own world through small screens and technology.
Just like us.
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NOTE: This piece arose because one of my friends pointed me at the Clapton/Berry video; I’m sorry, but I don’t remember who that was! It was spurred onward by another friend when we floated the idea of a civilization going radio quiet with the growth of wi-fi (a known, suggested resolution of the Fermi Paradox that often goes by the moniker “the fiber optic objection”); I can’t remember who that was either! I must be losing it…
I’m pretty intrigued by the suite of solutions to the Fermi Paradox that involve the potentially stochastic nature of ETI…either because of what you discuss here, or just really short timescales for such civilizations. I imagine that if you could put a filter on your telescope that could magically “see” ETI civilizations, the sky would look like a winking christmas tree…with some lights burning bright and short and others flickering, some barely shining at all. This type of signal would be **very** difficult to detect, especially since we are swimming in our own miasma of radio leakage.
Let’s say we stop producing detectable radio leakage tomorrow…that would give our omni-directional broadcasts a temporal width of only 80 years (1930 – 2010)…but that is pretty good, if you think about it. Give SETI 80 years, and they should catch at least one of these “light bubbles” from another civilization. In fact, if you could filter stellar sources by age you might be able to use this to refine a target list for SETI…hmmm.
On another note, my colleague Ravi Kopparapu published an interesting article on finding alien artifacts:
http://www.sciencedirect.com/science/article/pii/S0094576511003122
His point: no matter what happens, at least one ETI has launched several artificial craft into the cosmos, and left a litter of debris on several planetary bodies. In fact, if we were going to send an interstellar robotic probe, chances are it would fetch up in the debris field of the system we send it to eventually. Maybe our asteroid belt is littered with robot explorers from another world!
Another related thought. If my friend Tom Murphy at Do the Math (http://physics.ucsd.edu/do-the-math/) is right about energy usage, no self respecting Type II or III civilization would allow itself to be bound to a planetary surface. What if all the long-lived ETI’s are flitting about in hollowed-out asteroids at near the speed of light sending narrow-beam laser pulses to each other? What the heck would that look like? Probably not repeatable enough to log as solid detection. Maybe that was the WOW signal 🙂
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