So you know the Great Filter, right?
It’s what happens when you look up at the stars and ask “Where the fuck is everyone”.
There are so many planets out there, yet it’s radio silent. The intelligent life to planet ratio is really, bad. So far we’re the only ones.
You gotta ask, why?
Enter, the Great Filter. Something, at some point in the pipeline, prevents planets from developing and maintaining intelligent life capable of electromagnetic communication.
We don’t know what it is. Maybe it’s a quirk of chemistry that makes the chance of multicellular life forming ridiculously low. Maybe it’s a quirk of biology that makes sapience incredibly rare. Maybe it’s a hyper intelligent space worm that eats any civilisation that makes too much noise. Maybe it’s runaway climate change.
The thing is, we really don’t want to be on the wrong side of that filter, because that suggests that an imminent demise is in our civilisation’s future. And with every discovery of non-intelligent life on other planets, it becomes increasingly likely that we’re on the wrong side of that filter.
Enter, the recent discovery of life on Venus. It means that we’re much more likely to be on the wrong side.
But, watching that debate tonight, I began to feel a sense of relief. At least if we’re on the wrong side of the filter, it’s not as though we’re wasting a once-in-a-galaxy chance. We’re just yet another civilisation that failed to get past that filter. I can live with being unexceptionally mediocre.
When accelerating an asteroid to near C with some slow-burn engines could make an essentially undetectable, doomsday, kinetic kill vehicle, it’s hard to imagine a universe where the best option isn’t to immediately kill any nascent civilization that pings its location.
Hard unpopular opinion: The great filter is that any sufficiently advanced civilisation will recognize new life being brought into the the world as inherently negative and dies out naturally
I think it might be that intelligence is rare. We have a lot of very clever animals on Earth so it seems like we can’t be special - if it wasn’t us it’d be the crows or the dolphins or the octopodes, right? But those aren’t actually independent samples, we all came from the same planet.
The asteroid that killed the dinosaurs wiped out 75% of species on Earth. There’s a distribution of different asteroid sizes that’d cause bigger or lesser extinction events. But that distribution has a giant spike at 100%, because an asteroid big enough to kill everything on the planet twice over is still just a 100%er. Our planet’s history is full of mass extinctions, but doesn’t have any extinctions that actually wiped out all life on the planet. If any of those hit 100%, there’d be no intelligent life.
On the other hand, most of the really interesting evolution happens right after a mass extinction. That’s where we get birds and mammals replacing the dinosaurs. Intelligence is a general-purpose adaptation that helps in a lot of niches, but smart animals aren’t going to suddenly take over niches that are already full of well-adapted animals. The evolution of intelligence might require a lot of mass extinctions. Which would mean planets that aren’t constantly rolling the dice on a total extinction are still stuck with dopey alien trilobites.
Anyway we’re not going to get to test Great Filter hypotheses without a whole lot of interstellar travel, so don’t worry about it unless you need a good science fiction premise.
if it wasn’t us it’d be the crows or the dolphins or the octopodes, right?
2.5B years of life on Earth, and we’re the first civilization (we are aware of anyway) that figured out how to do more than basic tool use. We’re the first animal that made industrial use of fire. We’re the first animal to invent concrete. We’re the first animal that developed amphibious transportation. We’re the first animal to split the atom. We’re the first animal to reach the moon.
I don’t think it’s a given that any of those others would have filled our roll. We have a lot going for us that is distinct to our species. We also killed off our six nearest ancestral cousins nearly 2M years ago. We may have eliminated any other inside-the-next-50M-years applicants in our climb to the top.
Anyway we’re not going to get to test Great Filter hypotheses without a whole lot of interstellar travel, so don’t worry about it unless you need a good science fiction premise.
I don’t think it will necessarily require our ability to move, physically, to other corners of the cosmos.
But it might require some hereto unknown level of scientific development to recognize an active extra-terrestrial civilization. There could be a lively extraterrestrial community living under the clouds of Jupiter or deep in the oceans of Europa. There could be extra-terrestrials happily doing their thing around Wolf 359 on a pair of planets we only just discovered in June of 2019. There could be an abundance of life in the center of the Galaxy where energy is far more abundant and resources are significantly richer.
And it could be that absolutely none of it is carbon based. It could be that all their technology is, subsequently, operating on wavelengths and via mechanisms that we don’t have the capacity to efficiently use or are yet to understand. We started using radio waves barely a century ago, ourselves. It could very well be that civilizations only use radio broadcasts for a century or two before switching to something more efficient. And if we’re not listening in the window during which that transmission is rolling through our skies, we’re just going to miss it.
We’re out here looking for another group of human-lives. And that might be extraordinarily rare relative to some organism that gestates naturally in the higher pressure systems of gas giants or through the accumulation of large amounts of radioactive material only found near dying stars. How much Ammonia-based life is there in the universe? How much Arsenic based life?
None, as far as we know today. But it’s theoretically possible, particularly under a different set of fundamental forces in which carbon life couldn’t exist.
Life was NOT discovered on Venus, phosphene (which should break down in venus’s atmosphere) is present in amounts that are not possible unless it’s being continually produced by some process, and one of those is potentially life
but they didn’t prove it’s that, could also just be geochemistry
