The famous Drake Equation suggests that our galaxy, and by extension most other galaxies in the observable universe, should be teeming with alien civilizations all eager to cross vast distances to probe our fundaments. But the fact is, despite decades of looking and despite all the conspiracy theory nonsense, we’ve zero real-world proof that anything is out there at all.
Hence the now-famous question: “where is everybody?”
What if the Drake Equation was as realistic as any solution to the question of how many angels can dance on the head of a pin? Let’s take a look to see why this may well be so.
First of all the Drake Equation (which we’ll call DE henceforth) makes some astonishing assumptions. Given that we know absolutely nothing whatsoever about the probability of eukaryotic (multi-cellular) life emerging even on our own planet, it’s a bit of a stretch to make the blithe assumption (as the DE does) that eukaryotic life is more or less inevitable on any planet that can theoretically have liquid water sloshing around on it.
Secondly we know nothing about the emergence of technology-creating life. Our own species has arisen because of a huge number of largely stochastic events, a small change in any one of which would have precluded our emergence. For example, if grass hadn’t evolved there would have been no savannah encroaching on the jungles in which our primate ancestors lived. Without encroachment, our ancestors would have remained in the trees and it is impossible to see how we’ve have been significantly different from chimps, orangutans, gorillas, and apes. Even after our ancestors descended from the trees and began to walk upright there was nothing whatsoever inevitable about our emergence, and had not some genetic alterations occurred in grains after the last ice-age (alterations that made the germ seed drop from the stem more easily and thus enabled the development of agriculture) we would never have started to group into villages, towns, and cities. And without that grouping, craft specialization would not have proceeded very far. If craft specialization hadn’t proceeded we’d never have developed any significant tools and we certainly would never have developed our modern technological civilization. So the blithe DE assumption that eukaryotic life inevitably leads to a technological civilization is, to put it mildly, quite a stretch.
The other thing the DE skips over is the problem of timing. Space is very, very, very big. There’s also this annoying limitation called the speed of light, which is approximately 300,000 kilometers per second. That’s it — nothing can go faster than the speed of light. So for all practical purposes any technological civilization would need to exist fairly close to us, perhaps no more than a few hundred light-years away. Further away than that, not only does physical travel across the distance become utterly infeasible but information transfer is likewise rendered improbable because of the energy required to beam signals across such a vast span of space.
Worse still, if a technological civilization were to emerge elsewhere close by it would have to exist at precisely the same moment in time that we ourselves do. In other words, not only would lots of other very problematic things have to happen on another world in order to give rise to a technological civilization we could interact with in some way, these things would have to occur at precisely the same time these things happened for us too. This is because the overwhelming probability (for a variety of sound evolutionary reasons) is that any technological civilization will self-destruct once it reaches a certain point of development. Just look at our own species for confirmation of this hypothesis. It’s unlikely we’ll be around in a thousand years, never mind ten thousand or more.
Once you factor these considerations into the DE you end up with a very small chance of anything being “out there” at the same point in time as ourselves. And it only gets worse from here. What, for example, would induce another technological civilization to expend huge resources in order to beam signals out into surrounding space? For all that a few people are terrified of the idea our TV and radio signals are going off to alert some advanced species that will come and enslave us (after the requisite anal probing, of course) the fact is those signals start off very weak and attenuate by the square of the distance traveled. Which means by the time they’ve reached the Oort Belt they’re essentially non-detectable. And that’s still well within the heliotrope. Forget about old episodes of Star Trek being intercepted by some distant world decades from now — it is a physical impossibility. So any species that wanted to send a message of sufficient strength that it could be detected from far off would need to invest enormous resources. Why would they do that when there would be plenty of competing projects of a far more urgent nature?
The final reason we don’t need to invest in rectal protectors is also to do with distance. Even with near-magical technologies at their disposal, an alien civilization would be constrained by that 300,000 kps limit. If we had neighbors orbiting the nearest sun to our own that’s a separation of:
And that’s technically known as “a f*cking long way away.”
Let’s say our alien friends have developed whizzy tech that enables them to travel at 33% of the speed of light, which is around one million kilometers per second. At that speed we could travel from the Earth to the Moon in less than half a second. That’s fast. But it still means our interstellar probe-merchants would need twelve years to reach us and twelve to go home again, assuming near-instantaneous acceleration and deceleration, which of course is impossible because of (a) energy requirements, and (b) the concomitant forces would turn any alien into pulp. So we’d get mechanical probes, perhaps, but almost certainly not anything containing a life form. But we haven’t seen any mechanical probes and that’s because of the other problems with the DE assumptions.
Some people imagine that black holes could solve the problem of distance because of what’s popularly known as “the wormhole effect.” But that’s only because these folk haven’t looked at the math. It’s true that a pair of black holes can be entangled and thereby connected by what’s known as an Einstein-Rosen bridge. The problem is (a) anyone falling into a black hole would be torn apart by tidal forces, and (b) the ER bridge gets longer at a rate of expansion greater than any possible traverse. So even if you could somehow get into a black hole without being torn apart, you’d be like someone trying to walk along a path between your front door and your neighbor’s front door where the path extends faster than you can run along it and thus the neighbor’s door gets further and further away no matter how quickly you move. So that’s the end of sci-fi wormhole magic.
Chances are, at this moment in time, we’re totally alone for all practical purposes.
The main good news is that the more impressionable among us can relax their sphincters. The other good news is that we’re highly unlikely to fall prey to a marauding advanced civilization so there’s no need to learn Klingon. The sad news is that as far as intelligent life is concerned, we’re it. We’re not very intelligent and we’re destroying the fragile world upon which we depend. So instead of hoping or fearing that there’s “someone out there” who will either save us or conquer us we should focus a bit more on trying to be a bit less unintelligent ourselves before it’s all too late. Technological civilization has arisen precisely once in four billion years on Earth. After we’ve messed it all up and exterminated ourselves, it is highly unlikely to arise again. We’ve got one shot. We need to make it count.