What do you think the Great Filter is?

The Great Filter is the idea that, in the development of life from the earliest stages of abiogenesis to reaching the highest levels of development on the Kardashev scale, there is a barrier to development that makes detectable extraterrestrial life exceedingly rare. The Great Filter is one possible resolution of the Fermi paradox.

https://en.wikipedia.org/wiki/Great_Filter

The Fermi paradox is the discrepancy between the lack of conclusive evidence of advanced extraterrestrial life and the apparently high likelihood of its existence. As a 2015 article put it, "If life is so easy, someone from somewhere must have come calling by now."

https://en.wikipedia.org/wiki/Fermi_paradox

Personally I think it's photosynthesis. Life itself developed and spread but photosynthesis started an inevitable chain of ever-greater and more-efficient life. I think a random chain of mutations that turns carbon-based proto-life into something that can harvest light energy is wildly unlikely, even after the wildly unlikely event of life beginning in the first place.

I have no data to back that up, just a guess.

littlecolt ,
@littlecolt@lemm.ee avatar

I would say it's the size of the universe and the fact that it is still expanding at an accelerated rate.

If the speed of light is really the "top speed" of the universe, it is inadequate for interstellar travel. It is barely good enough for timely communication, and not really even that.

Life can be as likely as it wants to be, but it seems to me that we're all quite divided, to the point of not being able to communicate at all with other potential intelligent species.

androogee ,

Isn't the fermi paradox specifically dealing with detection tho? Not just travel or communication.

littlecolt ,
@littlecolt@lemm.ee avatar

I suppose I was focusing on detecting some sort of communications. It still matters that when we see objects at great distance in space, it's the objects in the distant past

Tlaloc_Temporal ,

This universe being unfriendly to interstellar and especially intergalactic travel would seriously hamper a galactic civilization, and thus be less likely for us to notice them.

There might be hundreds of civilizations out there, each having only expanded to a few dozen stars, not caring to go further. Even the makeup of the interstellar medium might be incredibly dangerous, basically necessitating generation ships to cross. Large scale expansion might simply be too hard.

SLVRDRGN ,

That expansion at an accelerated rate - that's just so eerie when you think about it. The furthest objects we can see right now will slip away out of reach forever for the next generation, and so on. It's crazy to think that as time goes on, there will be less and less universe to observe.

littlecolt ,
@littlecolt@lemm.ee avatar

One of the weirdest facts. One that really makes you feel so small.

androogee ,

That's something really interesting, though. When we look at distant objects, we aren't limited by the distance they're at right now. We're limited by the distance they were at when they emitted the light.

So the observable universe is still growing because the edge of that bubble is such a long time ago that everything was still much closer together.

SLVRDRGN ,

But the light that reaches us is constantly getting stretched (red-shifted), so I'm not sure that our bubble is growing. Instead when they're stretched too thin, we won't be able to see it. I'm not 100% sure on the expansion rate of the universe and the pace of red shifting.
Also, eventually all the galaxies are expected to be pushed so far away from each other due to the pressures exerted by Dark Energy, that soon we'll only be able to see just the stars of our Milky Way.

Martineski ,

Time.

Cryophilia OP ,

Is on my side

bamfic ,

Yes it is

ShittyBeatlesFCPres ,

For a technological civilization like ours, I think it’s just that Earth/humans are weird and we’re past the main ones (like going from single-cell to multi-cellular organisms).

Having to overcome the physical obstacles on other planets rules out the type of spacefaring technological civilizations like ours. No matter how intelligent a civilization on a water world is, it’s not starting fires, much less building rockets. Just getting out of the water would be their space program. Even a totally Earth-like planet that’s a bit bigger and has an intelligent species wouldn’t be able to get to space with chemical rockets.

And also, humans are weird. It could be as basic as “we have hands for building complex tools.” We have a seemingly insatiable need to compete and explore, even beyond all logic—maybe no other intelligent species wants to strap someone to a rocket and send them to space because it sucks up there. We’re violent: without WWII and the Cold War, do we even have a space program?

So many things had to come together to create an intelligent, tool-building species with hands that lives on a planet with the right balance of land and water. As far as we know, it never even happened on Earth before and even then, we had thousands of years of civilizations before anyone was dumb enough to strap themselves to a rocket just to see what would happen.

Cryophilia OP ,

I definitely subscribe to the "humans are insane" theory of galactic lifeforms

MrMobius ,
@MrMobius@sh.itjust.works avatar

There is a great video about the Great Filter by Kurzgesagt/In a Nut Shell. If I remember correctly, in it they say we can guess at which stage the filter is by how evolved extraterrestrial life forms are.
So it's actually great if we find a lot of bacteria or other primitive life forms, that would mean we probably already have overcome the Geat Filter on Earth.
On the other hand, if we find many alien ruins of several civilizations at or above our technological level... Well, our greatest challenge might be coming.

Cryophilia OP ,

Honorable mention: we haven't detected alien probes, because intelligent alien societies haven't begun consuming the galaxy with exponential numbers of self-replicating robotic probes, because that's just a really bad idea:

Simple workarounds exist to avoid the over-replication scenario. Radio transmitters, or other means of wireless communication, could be used by probes programmed not to replicate beyond a certain density (such as five probes per cubic parsec) or arbitrary limit (such as ten million within one century), analogous to the Hayflick limit in cell reproduction. One problem with this defence against uncontrolled replication is that it would only require a single probe to malfunction and begin unrestricted reproduction for the entire approach to fail – essentially a technological cancer – unless each probe also has the ability to detect such malfunction in its neighbours and implements a seek and destroy protocol (which in turn could lead to probe-on-probe space wars if faulty probes first managed to multiply to high numbers before they were found by sound ones, which could then well have programming to replicate to matching numbers so as to manage the infestation).

grrgyle ,
@grrgyle@slrpnk.net avatar

Oh my god, that's such a stupid and simple way to kill a galaxy, but also what a great plot twist that would make in a story. Like the big reveal over why the galaxy has always been at war with itself. Exactly the kind of nihilism I'd expect from an Altered Carbon or its ilk.

Thanks for sharing!

Cryophilia OP ,

You might like the paperclip maximizer thought experiment

Also an excellent clicker style game called Universal Paperclips

grrgyle ,
@grrgyle@slrpnk.net avatar

Thanks I have heard of this kind of problem before, just not in an adversarial space war context, with like opposing forces

notabot ,

There's an easier and more reliable way to limit replication; don't hive them the means to create a small but essential part, and instead load the first probe woth many copies of it and have each replica take a set percentage.

For instance, have the probe able to replicate everything but its CPU, and just load up a rack of them on probe 0. Every time it replicates itself it passes half of its remaining stock to the replica and they both carry on from there.

retrieval4558 ,

It's gotta be the development of what we recognize as "intelligent". Our brains are not the goal of evolution, just a weird thing that happened.

CarbonIceDragon ,
@CarbonIceDragon@pawb.social avatar

My suspicion is that it's abiogenesis, but it's only a suspicion that I can't have any certainty of

NeptuneOrbit ,

Definitely the simplest answer and aligns so far with out observations.

Kyrgizion ,

Nah, I'm willing to bet there is actual physical life in our very own solar system (apart from all life on Earth, of course).
Europa's oceans for example have a decently high probability of hosting microbial life.

Of course, discovering primitive life all around us would be a bad sign the great filter is still ahead of us instead of behind us...

Kyrgizion ,

The most boring one: most species off themselves before they fully get off their starting planet. We will go the same way. Take your pick from climate change, war, pandemic, ... or even a combination of several!

nova ,

I agree. The threshold for becoming the "dominant species" of a planet is so low that the species still has its primal wiring for tribalism, competitiveness, etc. by the time it can build rockets. We humans should've had more time in the evolutionary oven to become more empathetic and cooperative for longer-term survival. Instead we have people willing (and able) to literally burn the world down to become richer or more powerful. And we have most of society cheering them on.

We've been on the verge of destroying ourselves for decades now, and humans have just barely started doing space stuff (a blink compared to the life of the universe). How in the world can anyone expect us to get to Dyson sphere levels of progress with how fragile our existence is?

jballs ,
@jballs@sh.itjust.works avatar

Unfortunately, I think this is the most likely scenario. Going from our modern technology levels, which are more than capable of destroying the world, to Dyson spheres is a huge leap that will take who knows how long (decades? centuries? millennia?).

Before that happens, we have to live together on a planet without blowing ourselves up or making the planet uninhabitable. As technology continues to advance, walking that knife edge of survival seems more and more difficult. The pessimist inside of me says that no civilization has been able to accomplish it.

Cryophilia OP ,

I disagree with your last point. I think we'll be at Dyson sphere levels in a thousand years, easily. Maybe two thousand if we an hero ourselves.

HANN ,

Even if you had a super intelligent species that can make Dyson spheres and travel at the speed of light the observable universe is beyond vast. I don't know much about cosmology or our ability to detect light but given humans have only been looking into the sky for a couple centuries, not being able to see a thimble in the ocean seems like a non issue. I think if you scale the observable universe down to the size of earth the speed of light becomes 0.05 mph.

fart_pickle ,

I read an article about Fermi paradox (I cannot find the link) that stated the humans are one of the first intelligent beings in the universe. That's why we haven't encountered any green men so far. We just might came too soon to the party.

Cryophilia OP ,

Definitely possible. I've read that the projected end of our sun is a "black dwarf", and that our sun's generation of stars is so young that there currently aren't any known black dwarf stars anywhere in the universe.

pelletbucket ,
@pelletbucket@lemm.ee avatar

seriously though, I think life on other planets probably just usually evolves underground, so even if they develop some sort of intelligence they're not looking up at the sky so they have no motivation to explore beyond their atmosphere no matter how advanced they get.

there was a planet in The hitchhiker's Guide to the Galaxy universe that had thick cloud cover so that people never even conceived of an existence beyond their planet. when a spaceship crashed there, it never even occurred to them that it might have come from the sky

Foni ,
@Foni@lemm.ee avatar

Energy needed to leave your planetary system vs energy available on your planet of origin.

We have not yet overcome it and I am not sure that we will achieve it.

Cryophilia OP ,

Well, we've already sent a couple of probes out of the solar system, but they're not really going fast enough to have any meaningful interstellar impact.

Foni ,
@Foni@lemm.ee avatar

Yes, but I mean leaving the planetary system not only with isolated elements, but with parts of our civilization.

magikmw ,

I think it's incompetence.

Cryophilia OP ,

Fermi, to aliens: "git gud"

HubertManne ,

I always thought of it as a series of tests or filters. Like a multistage filter. So like nukes is one, responsible environment management is another. Something like photosynthesis is more of a conditions for life to emerge thing to me really. If like can flourish to begin with then mutations are common enough that things like photosynthesis are inevitable.

SeikoAlpinist ,
@SeikoAlpinist@slrpnk.net avatar

We're still new to the game, and we have no idea what we're looking for.

Cryophilia OP ,

Same thing everyone is looking for.

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