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.

send_me_your_mommy_milkers ,
@send_me_your_mommy_milkers@lemmy.world avatar

One dope-ass 2 pole analogue ladder filter

yyyesss ,

the internet. or some other mass communication methodology. we have developed it before we're responsible enough to have it. there are too many bad actors ready to take advantage of our innate biological tribalism. we'll kill ourselves before we reach very far into space.

Lupus ,

Erasmus of Rotterdam (1466-1536), Dutch Renaissance humanist:"To what corner of the world do they not fly, these swarms of new books?"

I think people were concerned about that kind of scenario since the invention of the printing press, if not the written word itself.
Not trying to dismiss the destructive potential the Internet can and will have in the future, just pointing out, that this kind of fear is not new.

yyyesss ,

thanks, this actually makes me feel better.

also like an old man yelling at clouds. but better, nonetheless.

Martineski ,

Time.

Cryophilia OP ,

Is on my side

bamfic ,

Yes it is

rottingleaf ,

It's a society (or the whole humanity) becoming big enough to survive even when ignorant murderers are the elite and the majority of it, and civilized people - a smaller part and almost a property, similar to animals in a zoo.

When such a point is reached, the former will make the transition, and the latter will diminish over time. Then it just has no future.

A bit like with Ottoman empire and Qajar Iran, only on the scale of the whole humanity there won't be someone else to buy weapons and technologies from to keep going. Then some of the previously passable filters will kick in. Like hunger or resource scarcity.

bradorsomething ,

The Dark Forest theory is a great answer to this paradox. Anyone more advanced has a rational choice to exterminate all competition. We haven’t found any other advanced life because it hasn’t shown up and killed us yet.

KevonLooney ,

Why would they eliminate the competition if it was way behind in technology? Do we eliminate uncontacted tribes because they might be "competition"?

If aliens exist they probably have rules against interfering with primitive species. We are more like a band of chimps than an uncontacted tribe.

bradorsomething ,

We don’t eliminate uncontacted groups any more because we’ve contacted everyone we want stuff from, and it didn’t work out well for them. Lower technology groups in the 1800’s submitted or were killed off. In a finite universe, any competition could one day try to take you out, so you take them out.

I don’t believe anyone can fathom another alien race, much less assign them ethical rules about interfering with other species. And apes are slowly being driven out of their habitat as we continue to expand.

weststadtgesicht ,

Who said that they eliminate competition that's way behind technologically? They haven't eliminated us, so apparently they don't.
But it seems plausible that they eliminate civilizations that are on the verge of becoming dangerous - still a great filter, but probably a bit further in the future.

RealFknNito ,
@RealFknNito@lemmy.world avatar

Hard to determine with what we know. We haven't met any other intelligent species which suggests we've passed the filter. Yet, making that conclusion before knowing there are no others to meet is too presumptuous. But, if I were to guess, I'd think the filter is adaptability.

We're superior to animals for being able to use tools, live in radically different climates, and shape every spot on earth into a livable climate. Even on Mars, the moon, and space. How else would a species venture through space if they can't adapt?

That might be too general a concept for the question though.

doctordevice ,

We haven't progressed far enough to be detectable by intelligent life in other star systems, even the closest ones. The filter can easily be in front of us. It could just simply be that interstellar space travel is too infeasible, so intelligent species never reach beyond their home system.

RealFknNito ,
@RealFknNito@lemmy.world avatar

Yet we haven't even found other planets with complex dumb life, much less ones with intelligence, communicative life. Nothing like what we have on Earth, not even close. Either space is too big or we're past the filter.

doctordevice ,

We are nowhere near advanced enough to say that life, complex or intelligent, doesn't exist anywhere near us. There is no reason to believe an intelligent spacefaring race would make themselves so obviously detectable that us stupid primates could see them. And for non-intelligent life, we've been able to confirm mere thousands of planets. We have a very long way to go before we can start talking about the meaningfulness of a lack of life signatures in the atmosphere.

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.

DeanFogg ,

Fear. Right now we're on the edge of facing fear or succumbing to it

Tudsamfa ,

We have had Millions of years of (presumably) intelligent Dinosaurs on this planet, but only 200.000 years of mankind were enough to create Civilization IV, the best Strategy game and peak of life as we know it.

So clearly, Civilization™ is what sets us apart.

Jokes aside, the thing evolution on earth spend the most time on is getting from single celled life-forms to multicellular life (~2 billion years). If what earth life found difficult is difficult for all, multicellular collaboration is way harder than photosynthesis, which evolved roughly half a billion years after life formed.

naevaTheRat ,
@naevaTheRat@lemmy.dbzer0.com avatar

Sort of fallacious to go from one case of time to happen and derive probability from it.

I'm no biologist but I don't think any of our models of super early stuff are sophisticated enough to speculate on what stages are the most or least likely.

Tudsamfa ,

You are correct, but that doesn't mean I can't speculate about it.

The ability to do photosynthesis is widely distributed throughout the bacterial domain in six different phyla, with no apparent pattern of evolution., according to this random paper I found on the internet (I'm not a biologist either).

What I can glance is that photosynthesis has (probably) evolved independently 6 time in Bacteria and 3 times in Eukaryotes.

Plants evolved to photosynthesise after photosynthesising bacteria already existed for billions of years.

(But then we have to also acknowledge that multicellular life evolved like 25 times in Eukaryotes, and the Eukaryote - aka Mitochondria-"Powerhouse of the cell"-haver- is the real big step as it only happened once to our knowledge).

CaptainBlagbird ,
@CaptainBlagbird@lemmy.world avatar

Maybe it's wisdom.

Every species that might have grown advanced enough, would have gotten over the point of fighting themselves. So they would be wise enough to have something like the Prime Directive in Star Trek (not interfering with less advanced species' until they reach a certain milestone).

janNatan ,

My favorite filter is the amount of phosphorous in the universe. Earth has an unusually high amount, and it's vital for life. I like this one, because as more stars die, the amount of phosphorous goes up, implying we won't be alone forever.

Anyway, look up "Issac Arthur" on YouTube for HOURS of content about the Fermi paradox and potential great filters.

Cryophilia OP ,

Thanks, I'll check it out!

janNatan , (edited )

I'm gonna add to this by saying phosphorus may be my favorite, but I think the most likely filter is just time, twice.

Do you know how unlikely it is that earth has been habitable for so long? Do you know how long life was single-celled? One of the theories for how advanced (eukaryotic) cells formed was the combination of at least three different branches of life into the same cell! Archaea (cell wall), bacteria (mitochondria/chloroplasts), and viruses (nucleus). Do you know how unlikely that sounds? Do you know how long it would take for that to happen randomly? Most planets probably aren't even habitable for that long. Once we became eukaryotic, we started progressing much faster.

Then, keep in mind, the life has to continue to exist for billions of more years while it waits for the advanced life to happen again within the same section of the galaxy. So, time is two filters - both behind us and in front of us.

PrettyLights ,

Throwing in another similar YouTube suggestion of John Michael Godier

https://www.youtube.com/channel/UCEszlI8-W79IsU8LSAiRbDg

Hugin ,

An alternative is we are among the first. Third generation stars are the ones that have planets with enough heavy elements to allow for complex chemistry. Sol (our star) is thought to be among the first batch of third generation stars in our gallexy.

Light speed does seem to be the upper speed limit for the universe. Talking that into account we probably haven't had a chance to see other early life as it would likely be spread pretty thin right now.

Cryophilia OP ,

Yeah, I have a gut feeling that a lot of the variables in the Fermi equation are a little too generous.

Kyrgizion ,

I do agree that in the grand scale of things we're actually very early. That alone would explain a lot.

sxan ,
@sxan@midwest.social avatar

This is my favorite, mainly because it's been well argued by some respectable scientists.

Another is that we're in a simulation, and aliens aren't part of it. There are also some very good statistics pointing to the simulation theory, from just sheer scale.

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.

cynar ,

I don't think there is a single filter. My personal gut feeling however is that the jump to "specialised generalists" would be a major hurdle.

Early human civilizations are very prone to collapsing. A few bad years of rain, or an unexpected change of temperature would effectively destroy them. Making the jump from nomadic tribal to a civilisation capable of supporting the specialists needed for technology is apparently extremely fragile.

Earth also has an interesting curiosity. Our moon is extremely large, compared to earth. It also acts as a gyroscopic stabiliser. This keeps the earth from wobbling on its axis. Such a wobble would be devastating for a civilisation making the jump to technological. Even on earth, we are in a period of abnormal stability.

I suspect a good number of civilizations bottleneck at this jump. They might be capable of making the shift, but get knocked back down each time it starts to happen.

Cryophilia OP ,

Speaking of our moon, the fact that it's roughly the same size as the sun as seen from earth and the fact that this is a complete coincidence blows my mind. Like there's no reason for that to be the case. Total eclipses like ours (where you can see the corona) are very rare.

cynar ,

Even more so, the moon is slowly moving away from the earth. A couple of million years ago, it would have completely covered the sun. In a couple of million years, it will not fully cover the disc.

A million years is a long time for humanity, but a blink on the timescale of moons and stars. We didn't just luck out with the moon's large size, but also with the timing of our evolution.

Cryophilia OP ,

That's nuts. In two million years, humans will be sighing and saying wistfully "if I had a time machine, I'd want to go back to the time of the full eclipses, like 2024"

Asafum ,

Earth also has an interesting curiosity. Our moon is extremely large, compared to earth. It also acts as a gyroscopic stabiliser. This keeps the earth from wobbling on its axis. Such a wobble would be devastating for a civilisation making the jump to technological. Even on earth, we are in a period of abnormal stability.

There seem to be so many coincidences that make our solar system unique that it's really upsetting lol It's like we are so perfect for stability because of things like Jupiter keeping the inner system "clean" of large impactors, our part of the galaxy being more "quiet" than typical as far as supernovae, stuff like that which makes it seem even less likely for life to exist anywhere else. :(

cynar ,

Life will almost certainly be fairly common, given the right conditions. On earth, it seems to have appeared not long after conditions made it possible. We either won the lottery on the first week, or the odds aren't actually that bad.

The problem is, we can't detect life right now. We can only see potential communicating civilisations. These are a lot rarer. We currently know of 1, humanity. That will change in the next few years. We have telescopes being designed/built capable of detecting the gasses in the atmosphere of an earth sized planet. While we won't recognise all life types this way, a lot will show up in abnormal gasses, e.g. free oxygen. This should help bound the possibilities a lot.

magikmw ,

I think it's incompetence.

Cryophilia OP ,

Fermi, to aliens: "git gud"

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