What do we do if SETI is successful?
132 comments
·October 20, 2025ricksunny
The new proposed protocol from IAA that the article references but does not link to: https://arxiv.org/abs/2510.14506
IMO a protocol that doesn't involve automated instantaneous backing up of data on a publicly-referenceable blockchain is worthless due to the apparently legitimate (in the eyes SETI researchers that a former SETI institute chairman references) concern about security services quietly stepping in the way.
(see my other comment for reference)
bluGill
The decision to not respond should not be considered an option for the UN. They can get a week max to decide what to respond, but a response needs to be sent quick. Otherwise you can assume someone will take the choice away and respond anyway. That someone could be a nation not liking the UN discussions, or it could be a rogue scientists with access to the powerful radios. (I doubt most of us could respond if we wanted to - even if someone is willing to break all laws they are either protected by too much security or they are too expensive to afford - but I guarantee someone who works at such a facility is willing to risk responding if governments delay too long)
Even if the UN makes a respond expect someone else to send a different one at some point.
joe_the_user
No individual is going to have the resources to respond to an alien signal unless it comes from Proxima Centari (very maybe) or not much further. No current earth broad would be easily recognizable from Proxima Centari with earth technology - a factor to consider when thinking about why entities aren't being easily detected. A powerful and very carefully aimed laser might work for greater distances but that wouldn't be something that can assembled in someone's garage.
But oppositely, if naturally defusing radio waves could be somehow detected from some further away location, the aliens would know already we're here and indeed lots about us so hand wringing about responding seems dumb there too.
wernerb
This is referenced in a sci fi book "The dark forest" of the series "The 3 body problem". It sets a convincing narrative that because of time taken for observation and response and development speed of society it is most likely that all civilizations that announce themselves would likely be a threat in terms of technological supremacy eventually to observing civilizations. In other words, we don't hear anything because any sufficiently advanced civilization would not want to risk being discovered. I.e., the "dark silent forest".
ricksunny
former chairman of the board of the SETI Institute John Gertz:
'In fact, the author has heard from serious U.S. SETI researchers that they are convinced that “men in black suits” will appear at their laboratory door the moment a detection is confirmed.'
Source: https://arxiv.org/pdf/1701.08422
gxd
My upcoming story game, a love letter to SETI and the Hacker News crowd, offers some perspectives on the question: https://store.steampowered.com/app/3040110/Outsider/
It will be out in 2 weeks!
em-bee
this is a question i have explored as part of my own scifi world building:
what is a realistic timeline for first contact, and how will it actually happen?
so we decode a message that we are pretty sure is of alien origin.
we send a message back and then wait a few decades or centuries.
we don't know how far away the origin of the message is. let's assume that it is less than 50 light years. that's still a round trip of 100 years. in other words it's a generational project, and we don't know if our first response is understood. we'll have to keep iterating until we can confirm that we are actually communicating. and then, the next step will be to try to understand each other.
with a round trip that long, even under the most optimal conditions just establishing a dialog based on say math is going to take a few centuries.
of course once we have a dialog, communication is going to speed up because then we can send longer messages.
but then it could still take anywhere from 500 to 1000 years before a common language is developed and we are able to share actual scientific and engineering knowledge.
once we reached that level of communication however, we can collaborate on developing FTL.
contrary to star trek, it was always my idea that FTL travel is not developed by the inhabitants of each planet/star system on their own, but only in collaboration across multiple such systems. maybe even more than two. driven by the desire to meet each other.
so from the point of the first received message it will be one millennium before we get to learn anything about and from these aliens, and another millennium before we can meet them in person.
and that's the optimistic projection. it could just as well take 10 times as long.
analog31
I predict that if FTL travel is possible, it will happen in our lifetimes, perhaps even as soon as 20 years ago.
null
anon291
Consider that, if the time separation is long enough via light then physical limits make it such that we do not ever have a chance of contact in which case this exchange is essentially indistinguishable from communication with supernatural beings.
Not that I believe they are the same, but many people will come to this conclusion and they would not be probably wrong. Causality is strange.
jay_kyburz
We fleshy humans will never visit other stars, but our AI children will be able to explore the galaxy with all the time in the world.
datavirtue
I'm in an AI cult. Send help. No don't.
gtech1
uhm, develop FTL ? Break causality and the universe ?
jay_kyburz
I don't know about faster than light, but as soon as we have real AI, it will simply be information and should be able to travel at about speed of light.
gmuslera
Time is a factor here. How close in time and space would be them?
If we get something coming from more than 100 light years away we might not have the technology to respond, and if we do it may not matter anyway if we are at risk of not having a technological civilization anymore 100-200 years forward. So the meaningful actions on those cases may not include answering back.
Then it will be the actual use of that message. Lets assume that we will decide that is a signal from a civilization that is out there. It will be a signal meant for us and for any other civilization that doesn't have the knowledge/culture level as them, meant for giving us a common ground for communicating back, or it will be something that just will tell us that someone intelligent is out there, but no mean to understand it?
So the options are that we find apparently benevolent aliens willing to contact us, or that we find out that someone is out there but no way to communicate/reach them. I think the second scenario is the most probable one, and how our civilization will react if widely enough will change with time, novelty at first and indifference a few years later.
kulahan
I cannot imagine any scenario where we're just 100-200 years away from "no more tech" that isn't purely total nuclear destruction. Even then, we'd probably be so close to getting back to a technological civilization that it'd be a blip in the radar at best if we're talking about a society that far away.
We lost 150 years of progress? That's okay, we had 800 more years to advance before the aliens showed up or whatever.
It's such a weird thing I see so many people assuming. We were down to like 16,000 humans on Earth at one point, and that was before we'd developed things that you could theoretically scavenge and jumpstart your tech.
People need to stop doomscrolling; I'm certain this is depression projected.
ruszki
When we have a nuclear destruction, and some of us survive, then we will have a problem which we cannot solve easily even today: absolute annihilation of the ozone layer. It won’t be a soft reset at all. If the ozone layer disappeared right now, its consequences would be absolutely catastrophic even with the current civilization completely intact.
leptons
In Carl Sagan's Cosmos, he talks about how many advanced civilizations could be out there capable of radio astronomy, and how as in our own experience, we have the capability to wipe out own civilization, so that would also be a factor in other advanced civilizations and could act as a limiting factor. There are many such factors other than nuclear destruction that could impact all functioning of an advanced society, rendering it nonviable.
The idea has nothing to do with "doom scrolling". Go watch some Cosmos...
wat10000
It was also before we'd burned all the easily accessible fossil fuels.
jandrese
Electrification of transportation is already well underway. Obviously ships and planes will lag behind, and may even be forced to use biofuels if we run out of fossil fuels, but the idea that the world will stop when we run out is outdated.
Green power generation is also making huge strides forward, and battery technology is improving enough to make fully green grids a reality. We already see articles about how some countries are managing to go entire days without burning any fossil fuels for power generation. This will increase over time despite what the doomsayers predict. We aren't there yet, but the progress is almost inevitable.
The bigger problem is that we've already burned so much fossil fuel that we are noticeably altering the climate. This is going to cause a lot of stresses in the future, especially in a post-collapse scenario.
smallmancontrov
We mined all of the easily accessible drywall gypsum too, I guess we wouldn't be able to have houses either and would have to live outside in the cold and rain!
kulahan
Thankfully, unless somehow everything manmade disappears, we'll have scraps of windmills, solar panels, and hydro electric generators - with that laying around, it's easy to eventually figure out the underlying concepts and rebuild them.
elbasti
With all due respect, I don't think you understand what the "worst case" scenario looks like for global warming, and how close we are to that scenario. For reference, check out figure 1 in this nature article [1].
That has warming by 2300 as 8C in an "emissions continue current trends" path.
Here's chatgpt giving a picture of what 8C warming looks like. Speculative, hallucinations, caveat emptor, etc...but to give a sense of proportion this, last time the earth was 8C *cooler* than now, ice covered 25% of the planet:
> At +8°C, Earth is fundamentally transformed. Large parts of today’s populated zones—South Asia, the Middle East, Africa, southern Europe, the southern U.S.—are functionally uninhabitable for humans outdoors. Wet-bulb temperatures regularly exceed survivable limits. Agriculture collapses across the subtropics; even mechanized, climate-controlled farming is marginal. Most of the world’s food comes from high-latitude regions: a narrow band across northern Canada, Scandinavia, and Siberia. Sea levels are dozens of meters higher, drowning coastal megacities; Miami, New York, Shanghai, and London are gone. Phoenix is lifeless desert. Seattle is coastal tundra, wetter but still survivable.
> Civilization persists only in fragments. Mass migration and resource wars have rewritten borders. Population is a fraction of 21st-century levels. Global trade, universities, and modern governance are mostly memories. Local, self-sufficient polities dominate. The United States as an institution likely dissolves or transforms beyond recognition—2 out of 10 chance of recognizable survival. Harvard or MIT survive, if at all, as digital archives or autonomous AI-driven knowledge systems—3 out of 10. The world would still have people and culture, but not civilization as we know it.
Edit: I would appreciate knowing why I'm getting downvoted when I added citations for *possible* warming paths (from nature!). Yes, the chatgpt explanation is speculative but I mean, look at the thread we're discussing.
stronglikedan
> So the options are that we find apparently benevolent aliens willing to contact us, or that we find out that someone is out there but no way to communicate/reach them. I think the second scenario is the most probable one
I hope the second scenario is the most probable. Any aliens that could contact us would already know we can't even get along with each other, much less them. Even the most benevolent of aliens should see us as a "problem". (I was going to say "threat" but who am I kidding.)
leeroyjenkins11
Get better camouflage so we don't get get found in the Dark Forrest. https://en.wikipedia.org/wiki/Dark_forest_hypothesis
>The name of the hypothesis derives from Liu Cixin's 2008 novel The Dark Forest, as in a "dark forest" filled with "armed hunter(s) stalking through the trees like ghosts". According to the dark forest hypothesis, since the intentions of any newly contacted civilization can never be known with certainty, then if one is encountered, it is best to make a preemptive strike, in order to avoid the potential extinction of one's own species. The novel provides a detailed investigation of Liu's concerns about alien contact.
smallmancontrov
Liu Cixin had to break the laws of physics -- badly, multiple times -- in order to make the Dark Forest game theory work. That's not a problem, fictional rules are good fun, but generalizing his conclusions back to the real world without sending them through a customs inspection first is a problem. See also: do the dinosaurs escape because the laws of chaos theory dictate that dinosaur zoos are mathematically impossible? Or do they escape because otherwise I wouldn't pay to see the movie and neither would you?
If we ground ourselves back in reality where the speed of light is probably law and the spooky aliens probably don't get to tamper the laws of physics, the actual game-theoretic winning move is always to grow voraciously, threat or no.
bluGill
Where the speed of light is probably law (our universe) there is no way aliens could reach earth. The only possibly scenario where earth is in danger is if we terraform and colonize mars (Venus would also do, or a few other large rocks), then we have a falling out and start a major war. The few survivors would not know if anyone is on Mars, but if so they might still be out to get earth so better be quiet. If you are not already in this solar system you can't get here in a useful timeframe no matter how long lived you are.
jay_kyburz
We should expand our definition of Aliens visiting earth.
If we received a signal (at light speed) that described how to build a physical alien computer, and then ran a program on that computer, which happened to be AI, we would have alien visitors.
lordnacho
But why do we think the aliens as a polity will behave in a way that fits into our own concept of competition between groups?
Couldn't they have some other way of seeing things?
bluGill
They could. However their different way might be worse than our concept.
Though survival of the fittest is likely a law and so they will have a concept of competition between groups of some form (though their definition of groups will be different) simply because those without will be destroyed by the first group that does have that concept.
ge96
Following that:
> The Berserker hypothesis, also known as the deadly probes scenario, is the idea that humans have not yet detected intelligent alien life in the universe because it has been systematically destroyed by a series of lethal Von Neumann probes.
smallmancontrov
Yeah but they clearly didn't do a very good job on Earth so how systematic could they be?
Don't get me wrong, it's a wonderful premise for a book which can simply mobilize a plot device to brush this problem aside. However, if we want to bring the conclusions back to reality they have to undergo a customs inspection which flags said plot device.
teekert
What would we become in such a universe? We would take a step back, it will become about survival again (I know it's like that on earth here and there), not about growing together, exploring. It's like Star Trek's mirror universe.
Sure I'd fight for humanity, but I'd be so disappointed. Maybe even enough to just give up.
(I have to admit I just could not make it through part 2 of the Three Body problem, it went to slow for me.)
sdwr
That's an allegory for life under authoritarian rule, not a literal alien contact plan
9dev
IIRC the author said there are no meta layers of meaning, it’s just honest to god fiction written to be entertaining. I’m struggling a little myself to accept that for the entire trilogy, but that’s that.
IAmBroom
Or, both.
cousinbryce
Bold to assume aliens will ascribe to something besides despotism
kulahan
You can't imagine that one single alien race anywhere will deviate from this?
Wouldn't that kinda imply that your vision on the topic is almost certainly wrong anyways?
general1465
As a pragmatic opportunist
- Setup a massive array of antennas in space for reception only
- Try to decode their radio traffic and understand how they are exchanging information
- Steal their their knowledge and use it to advance human race forward.
- Reduce all our electromagnetic emissions to minimum to deny them the same advantage. Forbid anyone from sending signal towards them so we have time to technologically catch up to them without them noticing.
Any kind of contact will ends up in abysmal disaster as we have seen in the past, when advanced civilization shown up on shores of less advanced one.
marcosdumay
If some species out there is trying to detect life by the organisms electromagnetic emissions... that's a dumb species.
no_wizard
Hopefully we never have the pleasure of discovering Prothean style ruins on a nearby planet and Pluto isn't actually a frozen mass relay. That one never ends well.
Though I personally love the idea of advanced, civilized extraterrestrial life. I hope it exists (statistically feels likely but yet to be confirmed). Even if it turns out we humans are at a near lockstep with another civilization it'd be game changing if we could communicate especially.
All that said, maybe there's a "galactic civilization onboarding" program once a species meets a sufficiently advanced criteria independently, with no outside intervention. Perhaps the universe will turn our ideas on their head, and assumptions may not apply.
Our understanding of the world, for however great it is, is still likely full of things we can't fathom and unknowns we don't know. Its fun to speculate but the reality is we are only basing most of our knowledge on how things might be in the universe based on our singular planet's path of evolution.
It makes it truly hard to think of what alternative life forms may exist.
BrandoElFollito
When I see what kind of information we sent out, I would not koof my breath.
We would learn that they are gelatinous beings who coi5nt in base 17 and show an antenna to say hello.
edflsafoiewq
You're unlikely to get any radio signal that isn't specifically meant for you.
general1465
If SETI would be able to catch their signal on Earth, then antenna array in the space aimed at them, far from Earth to prevent our noise could work.
IAmBroom
That's not how electromagnetic radiation works.
jerf
It kind of is. You're thinking directionality, but there's also the fact that optimal transmission will involve using compression and possibly encryption, which by its nature turns the signal into noise if you don't already know it's a signal. An optimal signal, which it seems reasonable to assume would be what aliens would be using by the time they're communicating across star systems, would be much more difficult to detect as a signal than something like an FM radio station, which puts a lot of energy into broadcasting a carrier that is there even if the station is transmitting total silence.
nh23423fefe
Efficient communication looks like noise.
wkat4242
This presumes they have the same nasty survival-of-the-fittest kill-or-be-killed attitude as humanity. Our evolution kinda created that but it doesn't have to apply everywhere. I think it's entirely possible that alien civilisations could exist that are a lot more symbiotic.
We have a saying in Holland "the innkeeper trusts his guests like himself" which seems to apply here.
hermitcrab
>Our evolution kinda created that but it doesn't have to apply everywhere.
Presumably any alien species was also shaped by evolution, so is also likely to be similarly competitive. Maybe you can escape your evolutionary past. But maybe not.
wijwp
They'd have to get through The Great Filter, so maybe they'd have avoided or have moved beyond some of our evolutionary downfalls.
layman51
I would hope so, but this whole situation reminds me of a quote from the writer William S. Burroughs: "This is a war universe. War all the time. That is its nature. There may be other universes based on all sorts of other principles, but ours seems to be based on war and games."
It is a bleak view. When I even think about the behaviors of some of the animals (e.g. seals, praying mantises) we share existence with, it seems like it could be accurate. On the positive side, the concept of the infinite game (e.g. culture) is what should give us hope.
anigbrowl
It doesn't even apply in this world. There are many examples of a more advanced civilization steamrolling a simpler one, but there are also examples of that not happening. It's by no means an inevitability.
Koshkin
Right; or, since they are not competing with us for resources, they could kill us just for sport.
wkat4242
Again the concept of sport imposes human concepts on a hypothetical alien culture.
There's no reason to assume their society would have developed along similar lines. I'm sure there's alien civilisations that are more aggressive than us, but also ones that are less so.
I don't think we'll ever meet any though as our lifespan is just so short on a universal scale. And FTL travel seems to be impossible otherwise we'd have seen signs of it.
Of course according to our current physics understanding it is also impossible but I don't think humanity is very smart yet. But this thing might be right.
thrance
Your are reasoning like a 15th century conquistador with spaceships.
> Any kind of contact will ends up in abysmal disaster as we have seen in the past, when advanced civilization shown up on shores of less advanced one.
Interstellar travel is mind-boggingly difficult and expensive. Even assuming 100% fuel-efficiency, it is basically impossible to conquer other worlds, and doing so would come at zero benefits for the homeworld, as anything that could be brought back from conquered exoplanets could be made for far cheaper and faster at home. Atoms are the same everywhere in the galaxy, no planet has any unique stuff that is valuable enough that is makes sense to haul it across the galaxy.
The one thing that is cheap to trade is information, so why not cooperate with everyone? Competition is useless as we've seen, so why not give away everything we know in exchange for everything they know?
general1465
We could give them everything what we know and they could give us back a relativistic kill missile. No reason to try to conquer a planet if you can just extinguish a protentional threat, which luckily was naive to be useful before extinguishing.
jay_kyburz
I'd be more concerned about some alien force moving through our part of the galaxy and we get stepped on and squashed like an ant on the pavement.
ivell
> Forbid anyone from sending signal towards them so we have time to technologically catch up to them without them noticing.
This is going to be difficult. Immediately there would be cults that would be inviting them to earth to salvage us.
hermitcrab
Shades of "Three body problem".
general1465
Yeah but they would need to transfer for a long enough time to be noticed and decoded by the other side, so it would easy to spot and eliminate them quickly. Unless they are a smart cult and managed to make some self unpacking and executing coding which they could send over radio.
bossyTeacher
Sounds like you read Remembrance of the Earth's Past
general1465
I did not, but it looks interesting, thanks for the tip.
HeyLaughingBoy
I didn't know Proust wrote sf.
leephillips
He did, but he called his SF novel In Search of Lost Earth.
allenrb
> What do we do if SETI is successful?
Beg to be saved from ourselves? Fire up the old electronic thumb? Open a theme restaurant?
kulahan
In the end, I kinda... don't care. Look up - there's nothing. There should be at least some alien civilizations trying to make their presence known. There should be some signs somewhere that could be recognized universally as either "stay away" or "come here". It really should be trivial to locate technological civilizations unless you've got some incredibly solid reason as to why EVERY SINGLE ALIEN CIVILIZATION IN THE UNIVERSE acts a certain way. Color me doubtful.
We have billions and billions of data points showing the Universe is empty. We have exactly one (1) data point showing it isn't. And that's us.
Besides, just look at the timeline. The universe has only been cool enough, with enough stable stars, with enough formed planets for potential life to form for a few billion years. Between that and the Drake equation, life alone is likely to be unreasonably uncommon. Life that forms after a planet becomes stable, doesn't have any planet-altering disasters, evolves to complex multicellular forms, evolves some kind of intelligence, becomes social, forms a society, advances technology, and starts exploring the universe...? Why bother? The math doesn't work.
Note: I'm not speaking about any KIND of life existing, I'm speaking about technological civilizations. My belief is that we are essentially the forerunners.
bluGill
When you look up remember that the majority of what you see is in the same sub-arm of the spiral arm of the milky way that we are in. Of those we can see a large number or binary systems - two stars orbiting each other. We fancy telescopes we can see a lot more of course.
All the power of stars, and most of them still are not powerful enough that we can see them even on a dark night! What chance does any alien have of sending a message that reaches us if the light from their star isn't even powerful enough to be easy to detect? It was suggested elsewhere that even if we find an alien, we probably cannot respond if they are more than 100 light years away just because we can't get a message out powerful enough that they can detect (I can't verify this claim but it is reasonable)
wafflebot
I have no doubt that civilizations are out there. Maybe a handful, maybe nearing infinity. But out there.
The problem is "out there" is so far away, we are all isolated on our own island worlds. An ocean of space so vast we cannot meaningfully traverse it with probes or radio, to say nothing of manned interstellar flight.
But it never gets boring for me to imagine what other civilizations there might be, and how they might be different from us and from each other.
pfdietz
Yes. The Fermi Argument strongly implies this sort of question is pointless, an exercise in wishful speculation.
squigz
The idea that humanity is the only civilization in the entire universe strikes me as the absolute height of human arrogance.
kulahan
Lots of things seem arrogant to lots of people, but without some logical basis, it's worth ignoring.
pfdietz
This is an ad hominem argument. It attacks a position not because it's wrong, but because if you advance it you're a bad person.
For a somber, deeply intellectual view of what could happen, I can't recommend enough Stanislaw Lem's His Master's Voice: https://en.wikipedia.org/wiki/His_Master%27s_Voice_%28novel%...
"Given that our civilization is unable to assimilate well even those concepts that originate in human heads when they appear outside its main current, although the creators of those concepts are, after all, children of the same age—how could we have assumed that we would be capable of understanding a civilization totally unlike ours, if it addressed us across the cosmic gulf?"