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What If We Haven’t Met Aliens yet Because They’ve Messed Up Their Planets Too? (lithub.com)
47 points by tejohnso 80 days ago | hide | past | web | favorite | 71 comments

> Think about it: Human beings are on a collision course with our own industrialization...


> We are consuming nonrenewable (or very slowly renewable) resources at an unsustainable pace. Coal, oil, and gas are finite resources...

It's hard to overstate just how much fossil fuel there is out there compared to demand. Beyond that, we're becoming more efficient at an even faster pace than we are using it.

> Even if there is a lot left, there is not an infinite amount left.

Plenty of nuclear, solar, wind, hydroelectric, etc.

> We are converting rainforests, which produce the majority of our breathable oxygen and consume the majority of the carbon dioxide, into land for farming or housing.

This is happening in the 3rd world, and will be arrested by minor effort on the part of the 1st world if it is ever made to care enough. The idea that we are going to run out of breathable oxygen is something that only a journalist could believe.

> Our population is growing so fast that our ability to provide food for each person will be in serious doubt within a generation, despite all of our scorched-earth efforts to extract more and more sustenance from the planet.

Whoa, has somebody been reading population projections from the 1970s?

> Meanwhile, climate change is threatening major coastline developments, some ocean ecosystems are in all-out collapse, and biodiversity throughout the globe is plummeting.

3 separate, though major issues, but none of which threaten civilization.

> We are in the midst of a mass extinction caused almost exclusively by our own actions. Who knows how bad things will get before we bottom out?

In my youth these sorts of people just joined doomsday cults. (The Jehovah's Witnesses are still in operation if anyone is looking. I'm sure that there are others.)

Real threats to civilization exist. The Earth's biosphere has been wiped out several times by large rocks from outer space. It seems likely enough however, that if we can survive the next 1000 years (order of magnitude), we'll have enough technology to create cross-planet ecosystems that are not so threatened from a large rock wiping out any single planet.

The issue with fossil fuels isn't how much there is left, it is how much more CO2 we can release into the atmosphere while keeping the place livable. More generally, the larger the economy the more energy we degrade, and the more entropy we generate (in the form of pollution and environment destruction).

Our economy today is possibly already too large for our long term survival, and event if it isn't I'd rather we avoid crossing the threshold unknowingly.

But off course no one ever died in a fire they themselves had started. Let's keep on fanning the flames.

isn't most of the breathable oxygen produced by phytoplankton in the oceans?

and the taiga/boreal forest of the far north.

We’ve probably got another 100 years of fossil fuels left at best. We’re still _increasing_ how much we’re burning every year.

That's why we need to shift to hydro and nuclear

Actually, most planets don't have plate tectonics, (and what is the probability of a dinosaur extinction event?) So their population is "first generation", and they basically don't have fossil fuels. So no industrial age, and no powerful ergols for rockets. When we'll get there, we'll find mostly Star Gate-like civilizations: non-technological civilisations with lots of slaves and manual work.

No fossil fuels doesn't nessesarily mean no industrial age. Many of factories and saw mills used to be located at rapids or waterfalls for the power and water access.

I suspect lacking a good surface fuel source might be more limiting. Imagine the difficulties making metal tools with no wood to burn.

Fossil fuels are even more accidental than that. Most of them come from the fact that woody materials evolved long before anything evolved that could break them down. Wood was the original plastic.

It's quite possible that we stand where we are as a result of a very long series of very unlikely events and conditions.

But we really just don't know.

Hope we find out someday. The laws of physics are cruel-- maybe someday we can see everything in a 100M light year radius to us is devoid of life, but theres still the other billions of light years where trillions of dice rolls are happening for a chance at civilization.

I am reminded of those few galaxies in Bootes Void who legitimately wouldn't be too wrong in thinking their galaxy was the observable universe until they could see beyond the dark.

Why would Boote Void residents not see all other galaxies? It’s just a relatively low density space nothing special about it. You’re probably thinking of Barnard 68 - dark nebula, and it’s too small to host a galaxy.

Sans fossil fuels, wouldn't we just have figured out how to scale something else? Ethanol maybe?

I think maybe we would have had slow industrialization until we figured out fission, solar PV, and good batteries.

Even if you have a planet that does not have large deposits of oil and natural gas you will have steam based Industrial Age once you get to that point you can use gasification to create what is essentially fossil fuel.


Gasification can be used with any organic mater, wood and hay are pretty common materials.

It might be slower but it would still get you there.

It would seem we are both ridiculously lucky and also quite unfortunate to have fossil fuels.

I am almost certain that we don't know enough to say that most planets don't have plate tectonics; even if one assumes that gas giants do not, they are certainly disproportionally represented in the sample of planets we know of, on account of being easier to detect, due to their size.

I believe that there is some speculation that plate tectonics is necessary to sustain the sort of environmental stability, over long periods, believed necessary for complex life to evolve.

> Actually, most planets don't have plate tectonics

I think that is speculation at best. Looking just at our local system, Mercury appears to have active tectonics, Venus is now believed to have active tectonics, Earth obviously does, and Mars is believed to have had them at one point if not currently. And there seems to be evidence of both tectonics and liquid water on Titan.

My favorite Fermi paradox solution:

The galaxy is populated, much like Earth. The power controlling our region has a policy of leaving us alone. End of story.

This requires no great filters or fantastic coincidences, and assumes galactic society is organized much like Earth.

Any kind of organisation at semi-galactic scale implies FTL communication at the very least, which violates everything we know about physics.

Another theory that doesn't require a great filter: The distribution of life may not be equal across the galaxy if it's truly random, we could be in a local minima and never meet another civilisation by the bad luck of where we are.

> Any kind of organisation at semi-galactic scale implies FTL communication at the very least, which violates everything we know about physics.

Never thought of the practicalities of that, so thanks for bringing it up.

I think you're overstating things. Sure, they wouldn't be able to watch the Superbowl at the same time or hold elections in the same decade. It would be a very different and slow moving kind of civilization than what we know.

But I don't see how that means it can't exist, in some form.

"by the bad luck of where we are"

Or perhaps the good luck of where we are

Or, the galaxy is populated, and every entity has developed a policy of leaving everyone alone, so as to avoid detection and subsequent annihilation by other entities. Because as soon as an entity speaks up, everyone else seeks to eliminate it in the fear that it might experience a technology explosion, growing quickly enough to meaningfully compete for resources...


Policy of leaving us alone is likely. The reasons are also likely to be mundane. Too far away. We are possibly too far behind or we are so sufficiently behind that bringing us up to speed won't help them or us. Besides, in our primitive ways maybe we have something they lack. Some aspect of diversity.

A more interesting answer is they are simply horrified or disgusted: look up "They're made out of meat!"

Not that hard to believe either. There is a civilization on Earth that the rest of us have agreed not to contact. [0] Occasionally they see our aircraft and we can only assume treat them as mythical beasts. Once someone tried to contact them and was killed.

Is it that hard to believe that our local aliens ignore us for the most part, that sometimes we see their spacecraft and mistake them for natural phenomena, and when one of them approaches illegally if they land in the wrong place they just get killed?

[0] https://en.wikipedia.org/wiki/North_Sentinel_Island

I wonder what they think about all the random garbage the floats onto the shore of their island

Except we're aware of them and they're aware of us.

What would be the "ne plus ultra" of irony is that a hyper-advanced civilization had a policy of leaving us alone because they greatly feared us due to the fact we were thousands of times taller than they are.

Or, its too much work for them to fund SETI research on their planet... and they find that they can spread through the galaxy faster, if they just wait for a civilization to a) announce their presence; b) nuke themselves to the stone ages; c) and leave lots of space for the aliens' 100-year starships to drop off a few million colonist to the 'intelligent' species that just nuked themselves. Slow and steady wins the race.

>The galaxy is populated, much like Earth. The power controlling our region has a policy of leaving us alone. End of story.

Or they just don't care to visit our solar system because there's nothing of interest here. I'm sure you can imagine a 18th century European surveyor sailing past a bunch of new islands, noting them on charts and tossing in the description "contains no resources" and then moving on.

Travel might be terribly expensive and slow even for advanced species, so the concept of "resources" would be meaningless.

Or maybe they've come, but only in very small numbers. They radio home and leave for the next system to explore.

Such as when Abel Tasman explored Australia and New Zealand in 1642, but didn't find anything of interest (trade opportunities) to the rulers in Europe of the time.

If we assume that an advanced civilization will develop machine intelligence on a large scale with efficient processors and vast energy resources, it's possible that they've already fully explored the nature of worlds such as ours, and they don't have any reason to monitor them further.

What if they have visited, a long long time ago. The lead explorer’s name happened to be “God”.

Fermi's counter argument is that there's been billions of years.

Even a slow moving star hopping civilization should have spread across the whole galaxy many times over by now.

The 18th century surveyor skipped some islands, sure. But by now they're all accounted for.

What would be the alien/human equivalent of an airplane that natives in uncontacted areas shot arrows at? I can't come up with a believable example for the aliens to be discussing back at home base.

Mistaking them for natural phenomena. Like asteroids.

> and assumes galactic society is organized much like Earth.

When has earth society ever successfully left something new and foreign alone?

If there is a 'galactic directive' to leave us alone, it's because we were seeded here. I.e. we are the aliens, and being observed as some sort of experiment

We have managed to at least ballpark numbers for many of the terms in the Drake equation.

Planets are common.

Given the speed with which life evolved on Earth it's also probably common.

That leaves four barriers:

1) Multi-cellular life. Looking at Earth that took billions of years--it's likely a hard barrier to cross.

2) Intelligence. It took hundreds of millions of years but there were a lot of steps, this doesn't seem like evidence that it's all that hard.

3) A term not in the Drake equation--effective lifespan of the biosphere. This is the main argument of the Rare Earths hypothesis. Most planets do not remain stable enough for intelligence for long enough for it to arise. Looking at our own world we can see that we have already used up 99% of that time, we barely eeked under the line. (We have only about 50 million years before solar warming can be countered by lowered CO2, after that we have several hundred million more habitable years but they won't be friendly to big, slow-evolving animals of the sort needed for intelligence.) This very well might be a substantial barrier.

4) Intelligence is destructive, species that can communicate do not remain in that state for long. Note, also, that a species that can communicate probably can in an eyeblink of galactic time do interstellar colonization. Even by slowboat they should spread across the galaxy in at most a few tens of millions of years. Also, once a species has reached this point it would be almost impossible to destroy--thus we can conclude no species in the history of the galaxy reached this point.

The product of these terms must be infinitesimal. Either we have been extremely lucky so far, or we are facing an almost insurmountable barrier to survival in the near future.

What if we can't detect them because we don't know what an intelligent advanced species looks like because we aren't one?

I suspect the Fermi Paradox has something to do with important things that our brains can't know, or even suspect, save for meta-speculation like this.

Carl Sagan rationalized the Fermi paradox in terms of nuclear annihilation in one of his Cosmos episodes, which was created during endgame of the cold war. The same episode introduced the Drake equation too.

This article framing the paradox in context of climate change is simply doing the same thing, framing it in context of our most pressing existential threats of the day. Also, like Sagan, implicitly overstating the impacts of those threats to us as a species.

Its a useless exercise and brings no new information to understanding the Fermi paradox and doesn't bring us anywhere closer to resolving it.

Edit and clarification, since I think some people take issue with what I wrote above:


Existential threats I mentioned, nuclear and climate change, are in their worst possible realizations will be planetary wide catastrophes which have the power to cause us, as a species, enormous harm.

But they do not measure up as the existential threats implied by Sagan or author of this article : so they are not answers to the Fermi paradox.

I am looking at these two things strictly from POV of the paradox, not as pressing policy issues.

That passage is something of an afterthought, from the epilogue of his book, but it's still disappointing he doesn't credit Robin Hanson for coming up with the Great Filter concept[1], or mention the x-risk[2] community which contemplates this stuff.

[1] http://mason.gmu.edu/~rhanson/greatfilter.html

[2] https://nickbostrom.com/existential/risks.html / https://wiki.lesswrong.com/wiki/Existential_risk

I was going to say the same thing. This post just reads like a knock off Great Filter concept with less analysis put into it. For example, environmental devastation is only one of many possible causes of Great Filter-like phenomena.

It is entirely possible that there are tons of intelligent alien planets for whom the predominant way of life is the way of the Amish. They simply choose not to use radio-telescopes just like the Amish choose not to use mechanical milking machines. The link has an interesting list of barred technologies. Do the meek inherit Vulcan? https://en.wikipedia.org/wiki/Subgroups_of_Amish

Still not a good answer for the fermi paradox, it only takes one to light up a galaxy.

Yes, but imagine you are a civilization, that is smart enough to develop the idea of a Fermi paradox. If you are the first such civilization, you believe yourself to be one among thousands in your galaxy -- but yet, you get no radio signatures (or other signatures) of intelligent life. You might conclude, that the very act of obtaining technology predisposes your civilization (and the others who disappeared before you) to a shortened lifespan. Accordingly, you assume (wrongly) that to transmit or seek out radio signals, is going to 'f' you up down the road. You, and the 2d civilization after you, and the third, etc., internally agree to go the Amish way... and you have an infinite loop that repeats.

Think what you are suggesting. In all the possibilities where life grows it evolves exactly in one sociological way as you suggested.

Yet the one sample we have, us, doesn't fit the pattern

We don't have a pattern, until we drive our population down to 1 million, or we find evidence of an existing or extinguished alien civilization. At the rate we are going, none of these three are going to happen in our lifetime. If only the Vulcan Amish could turn on a radio station... just once every 100 years, in celebration of their Vulcan Amishness... Maybe a pirate Vulcan Amish radio station. You can only hope.

This seems like the Occam’s razor solution to Fermi’s paradox:

1. Civilizations have a short “technological” shelf life eg when they can send and receive signals, say 200y

2. They are spread apart by space and time by natural distribution

3. The chances of two of them overlapping (eg civ a is transmitting during a time civ b will hear it) is very small

So nobody ever hears each other. Maybe If we were around for 5000 years we’d catch one.

But we won’t be.

In one of the many debates on this topic I've participated in, one of my favorite (because it is optimistic) scenario is that we are not alone and the other civilizations are waiting to see if we kill ourselves or not before they stop by to chat.

That line of reasoning started with, "If we knew then, what we know now, would we have claimed the new world for conquest?" There are examples that we would not, for example protecting Brazilian indigenous peoples who have not contacted the outside world from being visited by people. Would "modern" western Europeans wait for the native Americans to sail east and meet them? One could hope they would. With a careful understanding of infectious diseases and respecting their traditions and culture.

It is arguably the case that we have lost much in terms of culture, ideas, and diversity through genocidal colonialism. Would a more enlightened civilization decide not to go there? I would like to think so.

> are waiting to see if we kill ourselves or not before they stop by to chat

Waiting? For how long? How can they tell that we've passed the threshold of being in the group of species that won't off ourselves?

I'm more inclined to think that we may not be all that interesting to more advanced species or as the author writes that our time-span simply does not overlap with the time-span of any intelligent life close enough to signal us.

I'd wait for a self-sustained off-homeworld base.

i don't think our civilisations are enlightened enough yet, but I appreciate your optimism, and share your wishes. Once we solve the Psychopath-CEO-President-Capital problems, perhaps...

I still believe that the sheer scale of space time is the reason we’ll never run into intelligent life outside of our planet. People seem to assume there is no technological barrier to super fast travel, but perhaps there is a limit? This limit could be far from the type of speed and time required to visit worlds that may harbor intelligent life.

There is a universal limit in the speed of light. It could be considered a technological limit as well, in that no technology can likely actually be built to overcome it.

Even though there are plenty of vague handwavy theories about warp drives with exotic requirements like negative mass, the Fermi Paradox seems to suggest that no solution for FTL is practically feasible.

I’m talking about a realistic limit much closer that the speed of light. My point being, that perhaps there is an even closer limit that it hard if not impossible to overcome for an intelligent life that’s contained in a biological vessel. Given how things in space are measured in light years, perhaps the time it takes to traverse these spaces far exceeds any biological lifespan. Put it bluntly - everyone could be moving at each other, but given the distance apart they would still die off before meeting one another, because of the time differences involved.

Plot twist: we're the aliens.

Plot twist: aliens have already come to visit us on earth, but sadly humanity seems to forget, or struggles to distinguish between evidence and hoax.

How is that a plot twist? The situation is symmetrical.

I really enjoyed The Light of the Stars by Adam Frank, a professor in the University of Rochester’s Physics and Astronomy department.

Most of the book is a summary of life beginning on Earth, followed by a re-thinking of the Fermi Paradox taking into account our own anthropocene, and finishing with some numerical experimentation.


What if we haven't met aliens yet because no matter how you slice it, interstellar travel and communication just isn't worth it.

What if we have met them, but anyone who admits to it is dismissed as crazy?

What if we have met them, but they routinely sedate their subjects and administer a memory block?

What if we have met them, but only as random test subjects because they have no respect for us whatsoever, so they see no point in trying to establish diplomatic contact?

Besides, it's not like we have a world government yet. "Stupid primitives."

Light takes 4 years to reach the next closest star.

And yes, someone in a vessel traveling near-light speeds won't age all 4 of those years. But we do. It will be, for us, 8 years before someone hops to the next closest star and back.

Same with information from an unmanned probe. Even if we can beam it back at light speed, it will take years to get back here. And we're talking about going somewhere we know about.

In terms of exploration, forget it. Space is kind of infinite. Not knowing if there would be something when you get there is going to be a waste of years back here on Earth.

The times involved are too great for biological beings like us. But for our AI successors, who's personality can be uploaded anew to new versions of IT substrates, a million years would be nothing.

Interstellar travel, if it is happening, is being done by robots.

That follows another presumption I'm not comfortable granting.

That AI is possible. We don't understand intelligence. We don't. To presume we could recreate it is, at this point, wishful thinking.

And even giving you AI, they would have to decide that it's worth it.

Let me just straight up ask, what's the practical use? We're interested in interstellar travel because it's a way for us to expand our species. A completely artificial life form with an effectively eternal lifespan has no such concern.

Cutting edge theories concerning the space-time continuum and practical approaches to interstellar travel aren't really my bag, but Einstein said "Time is an illusion" and Stephen Hawking apparently did a lecture on the common fictional idea of a "warp" drive and that it's not necessarily a nutso concept.

I haven't bothered to read it, but it is available online:


I'm content to mostly limit my exposure to such topics to having my mind periodically blown by my adult sons, then fairly promptly forgetting most of what they said. Physics just isn't really my thing.

My hope is that someone discovers an exception to the theorem/theory that says nothing can move faster than light. Without FTL communication, and FTL travel, space exploration is simply too depressingly slow.

When an E.T race becomes capable of utilizing the amount of energy it would take to do interstellar travel in a reasonable amount of time, they can probably, accidently, or on purpose, use that energy to cause a lot of damage to a planet.

For example, an interstellar traffic accident at near light speed of a sufficiently massive object would cause a lot of damage to a planet.

Destroying a planet doesn’t seem like a big deal for space fairing civilization. Honestly there’s much more room and resources outside surfaces of planets

reminds me of the "Kurzgesagt – In a Nutshell" youtube video "Why Alien Life Would be our Doom - The Great Filter"[0] that discusses many of the same ideas!


The solution to the Fermi paradox can't be be something that most civilizations fail, it has to be a challenge that's impossible to pass.

The Fermi paradox posits that there should have been huge numbers of spacefaring civilizations for millions of years before mankind evolved. If you postulate a candidate great filter that lies ahead of humanity then it must have filtered out every single expansionist civilization in our galaxy up till now.

The solution that makes most sense to me is simply that we did the stats wrong when combining estimates of the factors of the equation, and our best guesses predict very few other civilizations: https://slatestarcodex.com/2018/07/03/ssc-journal-club-disso...

What if aliens do not use radio waves to communicate but something else like dark energy or something in the quantum realm?

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