Filed under: science fiction, Speculation | Tags: Fermi Paradox, Interstellar Travel, science fiction
Wow, didn’t realize I hadn’t posted in so long. I got busy with life and writing. Here’s something that I was originally going to put in the book, but it doesn’t really fit there. It’s thoughts about how human experience might explain the Fermi Paradox.
Now, for one thing, I don’t think it’s much of a paradox. After all, as XKCD explained in “Alien Astronomers”, it would be almost impossible for a radio telescope on Alpha Centauri to pick up our radio broadcasts. Military and research radar beams, yes, but not our ordinary chatter. One critical point is that broadcasting powerful radio signals takes a lot of energy, and that’s expensive. If it’s more cost effective to be efficient, then we’ll do it (as we have with broadcasting and intercontinental cable) and that makes us more radio-invisible. At our current level of technology, the galaxy could be brimming with civilizations, and we couldn’t see them, nor could they see us. Being blind isn’t much of a paradox.
Of course, the question is, why aren’t the aliens here already? If they’ve had even a million years’ more civilization, shouldn’t they have starships? Well, here’s another answer: starships are expensive, because at high speeds, they’re a drag. This came out of an arXiv paper (link), and the pop-sci version on Io9. The basic point is that for a starship traveling at high speeds runs into photons from the Cosmic Microwave background, and if it’s traveling fast enough, those collisions generate about 2 million joules/second in energy, which seems to act like frictional energy slowing the ship down. So not only does a starship have to hit those high speeds, it has to continuously generate more thrust as particle collisions slow it down. You can’t just accelerate a starship and coast to another star, except at really low speeds which would take thousands of years to get between stars. Do you know how to make a machine that continuously functions for thousands of years? That’s a non-trivial challenge. So there’s answer #2 for the Fermi Paradox: space isn’t slick enough to coast. At high speeds, the CMB acts like an aether and causes friction, requiring continuous acceleration.
Answer #3 for the Fermi paradox is the one I was going to stick in my book, which is about what the Earth will look like if the worst predictions of climate change come to pass, and humans don’t go extinct. This scenario could also explain the Fermi Paradox. Basically, in the roughly 500 years of the Industrial Revolution (and yes, I know that it was much longer in the run-up), we’ll have burned through all our fossil fuels, our available radioactive elements, minable elements from aluminum to phosphorus, groundwater, and so forth. After we use up all the cheap energy and readily available raw materials, we’ll be stuck recycling everything using solar and gravitational energy (or biofuels, PV, wind turbines, and hydropower, if you want mechanisms) for hundreds of thousands to millions of years, until the Earth can generate more fossil fuels. Perhaps we had a brief window in the 1970s when, if we’d gone for it and known what we were doing, we *might* have put a colony on the moon. Highly unlikely, but possible, and the chances of that colony surviving would be fairly low. We can’t get to Mars now (due to little problems like radiation in interplanetary space), and if we don’t get nuclear fusion to work real soon now (the 1970s would have been a good time for that breakthrough, too), we’re going to be downsizing civilization pretty radically in the coming century, rather than going to Mars or beyond.
Let’s assume that humans are relatively normal for sapient species, in the sense that we got our rapid spurt of technological advance by using up all the surplus energy that their planetary biosphere had squirreled away for the last 300 million years. By the time we understood the true state of our world and the galaxy, we also realized we were in trouble, because we were already going into a time of overconsumption and too-rapid population growth. By the time we become technologically sophisticated enough to possibly colonize another planet, we won’t have the resources to do so. Indeed, we’ll be forced to use any terraforming techniques we work out on the Earth just to keep it habitable. Once we’ve survived this peak experience, we’ll be a mature civilization (or more likely civilizations), but we’ll also be radio-quiet, highly resource efficient, and totally incapable of interplanetary travel, let alone interstellar voyaging.
That’s the #3 answer to the Fermi Paradox: scientific development marches in tandem with resource extraction, and it’s impossible to become sophisticated enough to colonize another planet without exhausting the resources of the planet you’re on. It’s possible that the universe is littered with ancient sophisticated civilizations that have already gone through their peak resource crisis and are quietly going on with their lives, stuck on their planets, kind of like kids who went to college to change the world and got stuck with crushing college debts and jobs that weren’t their dreams. In our case, we’ve still got a billion years or so left before Earth becomes totally uninhabitable, so it’s not horrible to be “stuck” here, on the one planet we’re evolved to live on. It’s just sad for those of us who thought that Star Trek looked like a really cool way to live.