Our universe is big. Like, really big. Like so big that it is impossible for the human mind to comprehend how big it us. If you were to travel from Earth to Pluto, and let’s say you were in a massive spaceship that could travel 40,000 miles per hour, it would take you over 20 years to get there. Pluto isn’t even at the end of the solar system – it goes on quite a ways beyond the former planet. And, our solar system contains just one star. There are over 200 billion stars in the Milky Way Galaxy. That’s just OUR GALAXY. And the Hubble Space Telescope site estimates there are hundreds of billions of galaxies in the universe. Some scientists estimate that there are over 10,000 galaxies for every grain of sand on Earth. So, yeah, pretty big.
Well, that’s a lot of data points to work with. Why we haven’t found life yet? Surely based on the laws of probability and chance, ONE of those galaxies has to contain life.
This is what puzzled Enrico Fermi. Fermi, you might know, was a 20th century scientist who popularized the apparent contradiction between:
high estimates of the probability of the existence of extraterrestrial civilization
humanity’s lack of contact with, or evidence for, such civilizations.
Somewhere out there, there should have been a civilization as intelligent as Earth that was able to colonize the galaxy, or at least have the capability to visit Earth or send satellite signals. And yet, here we are, still alone.
A few weeks ago I read a blog post on Wait But Why that explains the Fermi Paradox and the way scientists grapple with it.
One possibility is that there is no other intelligent life in the universe. This is a comforting thought – hey, we’re special! – but it also suggests that there is something that prevents truly intelligent life, something called The Great Filter. There is a wall that all life hits.
This means one of three things:
1) We made it! We are the only civilization that survived The Great Filter.
2) We made it! But we aren’t the only civilization that survived The Great Filter. Perhaps we’re just the first.
3) We’re doomed. The Great Filter is ahead of us.
Another possibility is that there is other intelligent life out there, but we haven’t heard from them for any number of reasons:
– Super-intelligent life could very well have already visited Earth, but before we were here.
– The galaxy has been colonized, but we just live in some desolate rural area of the galaxy.
– The entire concept of physical colonization is a hilariously backward concept to a more advanced species.
– There are scary predator civilizations out there, and most intelligent life knows better than to broadcast any outgoing signals and advertise their location.
– There’s plenty of activity and noise out there, but our technology is too primitive and we’re listening for the wrong things.
– We are receiving contact from other intelligent life, but the government is hiding it.
– Higher civilizations are aware of us and observing us (AKA the “Zoo Hypothesis”).
– Higher civilizations are here, all around us. But we’re too primitive to perceive them.
– We’re completely wrong about our reality.
But the scariest possibility is this one: There is only one instance of higher-intelligent life, a “superpredator” civilization. They are far more advanced than everyone else. They keep it that way by exterminating any intelligent civilization once they get past a certain level.
Wait But Why explains:
This would suck. The way it might work is that it’s an inefficient use of resources to exterminate all emerging intelligences, maybe because most die out on their own. But past a certain point, the super beings make their move – because to them, an emerging intelligent species becomes like a virus as it starts to grow and spread. This theory suggests that whoever was the first in the galaxy to reach intelligence won, and now no one else has a chance. This would explain the lack of activity out there because it would keep the number of super-intelligent civilizations to just one.
OK, I have to say, I love this stuff. No, I don’t love the possibility of being wiped out by a superpredator civilization once we invent hoverboards, but I love thinking about any of the above possibilities. It makes for a great conversation.
Any evidence of intelligent life would be the single most important discovery of mankind. And any type of communication with intelligent life would be the single most important moment in our history. And once we make that step, there is no coming back.