Posted: 03 Apr 2013 09:05 PM PDT
|Where is everyone?|
There’s no shortage of solutions to the Fermi Paradox. The standard ones are fairly well known, and we’re not going to examine them here, but they include the Rare Earth Hypothesis (the suggestion that life is exceptionally rare), the notion that space travel is too difficult, or the distances too vast, the Great Filter Hypothesis (the idea that all sufficiently advanced civilizations destroy themselves before going intergalactic), or that we’re simply not interesting enough.
But for the purposes of this discussion, we’re going to look at some of the more bizarre and arcane solutions to the Fermi Paradox. Because sometimes it takes a weird explanation to answer a weird question. So, as Enrico Fermi famously asked, “Where is everybody?”
The Zoo Hypothesis
Though it sounds like something from a Twilight Zone episode, it’s quite possible that we’re stuck inside some kind of celestial cage. ETI’s may have stumbled upon our tiny blue marble a long time ago, but, for whatever reason, they’re observing us from afar. It might be that we’re entertainment for them (like watching monkeys in the zoo), or that they’re studying us for scientific purposes. Regardless, they’ve invoked a hand’s off policy and they’re leaving us alone.
This idea was first proposed by John Ball in 1973, who argued that extraterrestrial intelligent life may be almost ubiquitous, but that the “apparent failure of such life to interact with us may be understood in terms of the hypothesis that they have set us aside as part of a wilderness area or zoo.” We could be part of a vast nature preserve that has been set off limits, free to grow unperturbed by intelligent life. It’s an idea that somewhat related to Star Trek’s Prime Directive in which civilizations are left alone until they attain a certain technology capacity. It’s also an idea that UFOlogists are partial to — the suggestion that aliens are essentially here, but observing us from a distance. Image: ssi.org.
And why not? It would be perfectly reasonable to conclude, especially in light of the Fermi Paradox, that the cosmos is filled with perils — whether it be an imperialistic civilization on the march, or a wave of berserker probes set to sterilize everything in its wake. And to ensure that nobody bothers them, advanced ETIs could set up a perimeter of Sandberg probes (self-replicating policing probes) to make sure that nobody gets in. Image: Cardens Design/Shutterstock.
The Whack-a-Mole Hypothesis
Imagine if there’s a kind of Prime Directive in effect, but that ETIs are hovering over us with a giant hammer ready to smack it down should it suddenly not like what it sees. These ETI’s would be like Gort from The Day the Earth Stood Still, intent on preserving the galactic peace. “There’s no limit to what Gort could do,” said Klaatu, “He could destroy the Earth.” So what is Gort or other advanced ETIs waiting for, exactly? One possibility is the technological Singularity. In the space of possible survivable Singularities, a sizeable portion of them might result in an extremely dangerous artificial superintelligence (SAI). The kind of SAI that could set about the destruction of the entire Galaxy. So, in order to prevent the bad ones from emerging — while giving the good ones a fair chance to get started — the Galactic Club keeps watch.
We’re Made Out of Meat
“Meat?”“There’s no doubt about it. We picked up several from different parts of the planet, took them aboard our recon vessels, and probed them all the way through. They’re completely meat.”“That’s impossible. What about the radio signals? The messages to the stars?”“They use the radio waves to talk, but the signals don’t come from them. The signals come from machines.”“So who made the machines? That’s who we want to contact.”“They made the machines. That’s what I’m trying to tell you. Meat made the machines.”“That’s ridiculous. How can meat make a machine? You’re asking me to believe in sentient meat.”“I’m not asking you, I’m telling you. These creatures are the only sentient race in that sector and they’re made out of meat.”
“They actually do talk, then. They use words, ideas, concepts?”“Oh, yes. Except they do it with meat.”“I thought you just told me they used radio.”“They do, but what do you think is on the radio? Meat sounds. You know how when you slap or flap meat, it makes a noise? They talk by flapping their meat at each other. They can even sing by squirting air through their meat.”“Omigod. Singing meat. This is altogether too much. So what do you advise?”“Officially or unofficially?”“Both.”“Officially, we are required to contact, welcome and log in any and all sentient races or multibeings in this quadrant of the Universe, without prejudice, fear or favor. Unofficially, I advise that we erase the records and forget the whole thing.”“I was hoping you would say that.”“It seems harsh, but there is a limit. Do we really want to make contact with meat?”“I agree one hundred percent. What’s there to say? ‘Hello, meat. How’s it going?’
The Simulation Hypothesis
If true, this could imply one of three things. First, the bastards — I mean Gods — running the simulation have rigged it such that we’re the only civilization in the entire Galaxy (or even the Universe). Or, there really isn’t a true universe out there, it just appearsthat way to us within our simulated bubble (It’s a ‘If a tree falls in a forest and no one is around to hear it, does it make a sound?’ type thing).
Another more bizarre possibility is that the simulation is being run by a posthuman civilization in search of an answer to the Fermi Paradox, or some other scientific question. Maybe, in an attempt to entertain various hypotheses (perhaps even preemptively in consideration of some proposed action), they’re running a billion different ancestor simulations to determine how many of them produce spacefaring civilizations, or even post-Singularity stage civilizations like themselves.
And for very good reason. David Brin has argued that the practice of Active SETI would be like shouting out into the jungle(Active SETI is the deliberate transmission of high-powered radio signals to candidate star systems). Michael Michaud has made a similar case: “Let’s be clear about this,” he has written, “Active SETI is not scientific research. It is a deliberate attempt to provoke a response by an alien civilization whose capabilities, intentions, and distance are not known to us. That makes it a policy issue.” The concern, of course, is that we may draw undue attention to ourselves prematurely. It’s conceivable, therefore, that our collective governments may some day decide to shut down all Active SETI efforts. We should just be content to listen. But what if everycivilization in the cosmos were to adopt the same policy? That would imply that everyone has gone radio silent.
As an aside, it could also be dangerous to listen: SETI may be at risk of downloading a malicious virus from outer space.
All Aliens Are Homebodies
We Can’t Read the Signs
Or, ETIs could use “calling cards” by exploiting the transmit method of detection(e.g. by constructing a massive perfectly geometrical structure, like a triangle or a square, and put in orbit around their host star).
And and as Stephen Webb has pointed out, there’s also the potential for electromagnetic signals, gravitational signals, particle signals, tachyon signals, or something completely beyond our understanding of physics. It’s also quite possible that they are in fact using radio signals, but we don’t know which frequency to tune into (the EM spectrum is extremely broad). More conceptually, we may eventually find a message buried in a place where we least expect it — like within the code of our DNA. Image: Arnold/Observatoire de Haute-Province in Paris.
They’re All Hanging Out At the Edge of the Galaxy
This interesting solution to the Fermi Paradox was posited by Milan M. Ćirković and Robert Bradbury.
“We suggest that the outer regions of the Galactic disk are the most likely locations for advanced SETI targets,” they wrote. The reason for this is that sophisticated intelligent communities will tend to migrate outward through the Galaxy as their capacities of information-processing increase. Why? Because machine-based civilizations, with their massive supercomputers, will have huge problems managing their heat waste. They’ll have to set up camp where it’s super cool. And the outer rim of the Galaxy is exactly that.
Subsequently, there may be a different galactic habitable zone for post-Singularity ETIs than for meat-based life. By consequence, advanced ETIs have no interest in exploring the bio-friendly habitable zone. Which means we’re looking for ET in the wrong place. Interestingly, Stephen Wolfram once told me that heat-free computing will someday be possible, so he doesn’t think this is a plausible solution to the Fermi Paradox. Photo credit diversepixel.com
The Phase Transition Hypothesis
This one is similar to the Rare Earth hypothesis, but it suggests that the universe is still evolving and changing. Subsequently, the conditions to support advanced intelligence have only recently fallen into place. This is what cosmologist James Annis refers to as the phase transition model of the universe — what he feels is an astrophysical explanation for the Great Silence.
According to Annis, a possible regulatory mechanism that can account for this is the frequency of gamma-ray bursts — super-cataclysmic events that can literally sterilize large swaths of the galaxy.
“If one assumes that they are in fact lethal to land based life throughout the galaxy,” he wrote, “one has a mechanism that prevents the rise of intelligence until the mean time between bursts is comparable to the timescale for the evolution of intelligence.” In other words, gamma-ray bursts are too frequent, and intelligent life is constantly getting wiped out before it develops the capacity to go interstellar. Looking to the future, however, given that gamma-ray bursts are decreasing in frequency, things are set to change. “The Galaxy is currently undergoing a phase transition between an equilibrium state devoid of intelligent life to a different equilibrium state where it is full of intelligent life,” says Annis.
Which would actually be good news.