So, I’ve been thinking about the Fermi Paradox. For those of you unfamiliar with it, the paradox was suggested in 1950 by physicist Enrico Fermi, when he asked, “Where is everybody?”
His argument was that it tool 4 million years for potentially space-travelling life to evolve on Earth, but the universe is a thousand times older, so there should have been plenty of time for other star-faring races to evolve and overrun the galaxy–and yet, we don’t see them.
Many (mostly depressing) solutions have been put forward, postulating some kind of Great Filter that prevents civilisations reaching the level of technology necessary for us to detect them. Candidates for the Great Filter include nuclear war, pollution, the impossiblity of interstellar travel, and killer robots that destroy life wherever they detect it.
On Earth, life evolved in response to a series of great extinctions and a variable climate. When the dinosaurs died out, mammals just happened to be in the right place at the right time. And when climate change started to make life on the savannah difficult for our ape ancestors, they had to get smart or die. They had to diversify their diet, learn to hunt, and ultimately harness fire and travel north, into Europe and beyond. We wouldn’t have survived without our intelligence and desire to explore. But an alien species in a more stable environment (a sub-surface ocean beneath the ice of a frozen moon, for example) might never have the need to develop those characteristics. They may have curiosity, but their options for exploration or technology would be limited by their environment. Their world would be covered by kilometres of ice, beyond which only vacuum lies; and they probably wouldn’t discover fire and smelting on a seabed. The desire to look outwards and seek new frontiers may be an extremely rare trait.
My own personal thoughts on the matter are that given the size and age of the universe, intelligent alien life almost certainly exists, but given those vast gulfs of time and space, we are extremely unlikely to ever meet them.
Look at the picture of the Andromeda galaxy accompanying this post. Look how many stars there are there. Roughly a trillion. If one of those stars housed an alien race at the same technological level as us, how would we ever detect it? You could drop a fair-sized galactic empire in there and unless they were using spectacularly noisy star drives to power their ships, we’d still never know they were there.
But it isn’t just the distance. Every light year we peer into the cosmos is a year back in time. Andromeda is 2.537 million light years away, so we’re seeing it as it was when the first Homo habilis on Earth were just beginning to experiment with stone tools. Given that some estimate it would take humanity only 100,000 years to colonise our galaxy using self-replicating, slower-than-light craft, that’s plenty of time for a species to have done the same to Andromeda. There might be whole reefs of Dyson spheres, and a galaxy-wide civilisation existing there right now, but we won’t know anything about it for another 2.5 million years.
Or perhaps we simply missed them. Perhaps that vast empire collapsed a billion years ago, and we simply can’t see their ruins.
Perhaps vast waves of colonisation have already swept through our own galaxy and we simply don’t recognise their traces.
In our own solar system, there are anomalies. Mercury appears to be the solid iron core of a larger planet, stripped of most of its crust. Venus spins in the opposite direction to the rest of the planets, and has the slowest rotation of any of the planets. Did something smack into it, or could its rotational energy have been tapped by a supercivilisation in order to power an interstellar wormhole, slowing (and reversing) its rotation? Or perhaps, given that it was once apparently habitable, could it and Earth have been targetted by planet-killing robots that wrecked Venus’s climate and dealt us the blow that birthed our moon?
We exist in deep time and deep space. I live in hope that one day, we’ll find evidence that we’re not alone, but realise that given the distances involved, any species we detect will most likely have gone extinct by the time we detect them. And alas, the same holds true in reverse. By the time we’re spotted, we may be long gone.
“Look on my works, ye mighty and despair.”