Fermi Paradox
Posted by simonebrunozzi 1 day ago
Comments
Comment by DamnInteresting 1 day ago
In short, the universe could be teeming with intelligent, radio-communicating species, but we will never know it unless we a) build an enormous radio telescope larger than the Earth; b) get lucky enough to pass through a direct hit from a narrow radio signal such as radar; or c) a civilization detects us and points a tight message in our direction.
[1] https://www.damninteresting.com/space-radio-more-static-less...
Comment by pavel_lishin 1 day ago
(I mention that last bit not to be thanked, but to give others an opportunity to do the same without it looking like you're soliciting: https://www.damninteresting.com/a-possible-future/)
Comment by DamnInteresting 1 day ago
So far, the GoFundMe has raised almost 50% of the $40k goal, so I'm cautiously optimistic. $40k doesn't seem like such a large amount of money until you need it.
Comment by jadbox 1 day ago
Comment by root-parent 1 day ago
They were going to upgrade us to a class B-1 civilization, but that was stopped after a second audit looked at the Politicians we have been electing....
Comment by jiggawatts 1 day ago
“After they killed their first hundred thousand other people, why weren’t they arrested and jailed?”
“Err…”
“And why not arrest them after they stole billions from the public they were supposed to serve?”
“Umm…”
“I can understand voters making a mistake once… but repeatedly voting in the same autocrat?”
“Well…”
Comment by pavel_lishin 1 day ago
Comment by M95D 35 minutes ago
Comment by tcp_handshaker 1 day ago
Comment by jiggawatts 1 day ago
Show them this video and they’ll immediately commence a mass sterilisation program, like we do with invasive mosquitoes.
Comment by goatlover 1 day ago
One problem with the idea is that not all aliens will be that advanced, and some of them should be detectable if they're that common, unless the super advanced aliens precluded their existence by being first.
Comment by tcp_handshaker 20 hours ago
Comment by pseudobry 10 hours ago
Comment by GlibMonkeyDeath 1 day ago
This is what I always thought was one of the major problems - unless an alien civilization is directly targeting Earth, we would never detect them. And our EM emissions are too weak to be detected by other aliens unless they stumble near us for some reason.
Comment by WithinReason 1 day ago
They found that airport radar systems, which sweep the skies for airplanes, send out a combined radio signal of 2×1015 watts. That’s enough for telescopes comparable to the Green Bank Telescope in West Virginia to pick up as far as 200 light-years away. [0]
200 ly is about 100k stars
[0]: https://earthsky.org/space/airport-radar-could-signal-earth-...
Comment by GlibMonkeyDeath 1 day ago
Seems that (r_d/(theta_e z))^2Pt_p ~ 100 hv (~100 photons at 3 GHz; a single 3GHz photon is about 2e-24 J) I'll drop this to 1 photon below.
Where
r_d = detector radius,
theta_e = diffraction angle of source,
z is detection distance,
P = 2e15 W (peak power of source, according to article) and t_p is pulse duration (say, ~5e-9 s).
Now theta_e ~ wavelength/(emitter radius), let's say the detector radius r_d ~ emitter radius = r ~ 3 meters for simplicity. Lambda = l = 3e8/3e9 m ~ 0.1 m) E_p = Pt_p ~ 2e155e-9 ~ 1e7 J (!)
(r^2/l)^2(1e7 J)/(1002e-24 J) = z^2, so z ~ \sqrt(100 m*(1e29)) ~ 3e15 m
But one light year is ~1e15 m. If I assume they have single-photon sensitivity in the microwave regime, then I can boost this result to ~30 ly. So about 1 order of magnitude less than their paper, but that is for a single photon of a single radar pulse. If you sum over many pulses from all the different radars that could be emitting over the integration time then, yeah, I guess 200 ly isn't ridiculous.
Curious what the cosmic microwave background is compared to this though...
Comment by GlibMonkeyDeath 20 hours ago
1) the receiver arrays are about 50x 6m diameter (3m radius) antennas (https://www.seti.org/projects/ata/) So that helps about 7x.
2) The 2e15 W/10 MJ/pulse has to be all the radars summed together already, so that is all the power available.
Take these two points together, the single photon detection limit is indeed about 200 ly.
Third: if we assume a 1 Hz detection bandwidth, I get ~200 photons/s for the CMB @ 3 GHz. I can't find the original paper (just the abstract) so they must assume 100-200 s integration time or so to get to an SNR of 1. So 200 ly is on the very edge of possibility - the example curves were calculated for 10x closer (~30 ly), as I would expect. Still, a lot further than a fractional light year!
Comment by M95D 28 minutes ago
Comment by venusenvy47 1 day ago
Comment by hackeraccount 23 hours ago
Comment by teravor 1 day ago
interstellar expansion is going to be a huge hassle, at a minimum you are going to be mass constrained and require a long period of investment in fuel (such as antimatter production) during which your competitors that chose to stay in the solar system will gain an edge and may strike before you leave. there isn't going to be MAD in space once you no longer rely on your planet of origin for anything truly important.
we should actually be deeply worried about the space race, because the early adopters will be making nukes out there and may come back to yank up the ladders.
Comment by gxd 1 day ago
https://store.steampowered.com/app/3040110/Outsider/
Made for the HN crowd :)
Comment by 22122 1 day ago
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Comment by goatlover 1 day ago
Comment by bediger4000 12 hours ago
Comment by chistev 1 day ago
Getting from the Sun to Pluto takes a very long time you might give up and close your browser tab.
Many theories attempt to explain why we haven’t yet encountered extraterrestrial civilizations. One possibility is that, given the immense scale of the cosmos, intelligent life may exist but is simply too far away for contact. Another idea is that while life may arise on other planets, it rarely, if ever, evolves beyond primitive intelligence. Intelligence here defined as ability to understand the cosmos and even leave their own world.
But there is another, more sobering theory. It suggests that when life does evolve to the point of intelligence, it eventually develops technology so powerful that it inadvertently brings about its own destruction. Whether through war, environmental collapse, or uncontrollable advancements, these civilizations may end themselves before they have a chance to explore the universe, or be found by others. This concept just described is called The Great Filter. The Great Filter proposes that there is some critical barrier or stage in the evolution of intelligent life that is extremely hard to surpass. [a]
There's a Wikipedia page dedicated to nuclear close calls between the United States and the former Soviet Union, and also present Russia. [2]
Perhaps the most famous close call is the one involving Vasily Arkhipov during the Cuban Missile Crisis [3] [2]
“Man has dominated man to his injury.” — Ecclesiastes 8:9
The Great Filter need not be caused by the intelligent beings themselves and can be natural like the asteroid impact that wiped out the dinosaurs. It's said that asteroids of varying sizes crash into Earth every X million years.
There's a counter argument to the Fermi paradox that perhaps we are too primitive for advanced alien beings to bother with us. One of my internet friends put it like this -
"there are counter arguments to the fermi paradox; one of which hires the analogy of, iirc, a guy looking over at a group of insects/anthill/ worms. he doesn't go wondering whether those worms are sentient enough to meditate on his thoughts. he doesn't think to sit back to converse with them. hell, they wouldn't understand him even if he tried. the paradox only holds water on the assumption that such civilisation is within the scope of our comprehension. " [4]
But there's a counter to that counter argument.
Yes it's possible that we're too primitive for advanced civilizations to bother about. But even in the case of ants and humans, isn't it true that we sometimes try to interfere with their lives just to see how they'd react either for fun or just sheer curiousity?
Yes, it's true that we might not be able to comprehend alien species. After all, they evolved in worlds different from ours. But, any sufficiently advanced civilization would understand Mathematics. Mathematics is a universal language and for them to be scientifically advanced means they understand science. They could, if they desired, find a way to communicate with earthlings using the universal language - Science. Carl Sagan made this point in one of his books and I think it was Pale Blue Dot (highly recommended).
I've shared some of my thoughts about aliens on my blog posts which my comment here were from. [4] [5]
[1] https://www.joshworth.com/dev/pixelspace/pixelspace_solarsys...
[2] https://en.wikipedia.org/wiki/Nuclear_close_calls
[3] https://en.wikipedia.org/wiki/Vasily_Arkhipov
[4] https://www.rxjourney.net/extraterrestrial-intelligence-and-...
Comment by huseyinkeles 1 day ago
“What if we finally got visited by aliens but the most important event in or history was simply an intergalactic roadside picnic for the aliens?
They don’t even bother with us ants. They just pull over have some fun for a couple of hours and leave a mess behind…”
Comment by chistev 1 day ago
Thanks. Haha.
Comment by smitty1e 1 day ago
Given the complexity of the Periodic Table, molecules, DNA, &c can we agree that life is a low-probability event?
Previous paragraph omits the contextual perfection of our planet/solar system.
Seems fair to assert that we are a one-shot deal, until proven otherwise, here on Terra Fermi.
Comment by chistev 1 day ago
Given how quickly life started on Earth after Earth's formation, it seems like it isn't a low-probability event, but it still might be considering it's the only place we've found life (not that we've made a dent in our search of the cosmos for life).
"Wind back the tape of life to the early days of the Burgess Shale; let it play again from an identical starting point, and the chance becomes vanishingly small that anything like human intelligence would grace the replay." - Stephen Jay Gould.
> Previous paragraph omits the contextual perfection of our planet/solar system.
It's perfect because it's the world we grew up in.
Comment by smitty1e 1 day ago
The repeatable experiment would be another universe itself.
Cutting to the chase and declaring you the winner of the discussion.
Comment by api 1 day ago
Let say our civilization lasts for a million years. That's a blip.
We are searching across tens to hundreds of light-years for just our galactic neighborhood as well as cross time spans in the billions of years.
Comment by krapp 1 day ago
Life is rare, intelligent life is more rare, intelligent technological life is even more rare and inherently unstable, intelligent technological life maintaining political and cultural stability long enough to discover space travel is harder, the actual space travel is harder still, interstellar travel is harder still, the universe is vast, electromagnetic signals diminish into the CMB over time and distance, we may simply not see them, they may simply not see us, they may see us and simply not care. Everything, everywhere, all at once and sometimes you just get sucker-punched by an asteroid or a gamma ray burst or your sun just explodes.
The universe is the most complex and complicated thing there is, and there are more unknown unknowns than stars in the sky.
Comment by goatlover 1 day ago
Comment by soupspaces 1 day ago
Comment by jiggawatts 1 day ago
As species become more intelligent, develop digital technologies, and their equivalent of the Internet, they become interconnected.
Interconnectivity is limited by the speed of light. Even here in Australia, the "lag" is very palpable. Conversely, whenever I visit the US, suddenly every web site provide instant satisfaction instead of frustrating delays.
As the speed of artificial intelligence increases, these delays become exponentially limiting. There's a point where you want to be in the same city, or even the same data centre as everything and everybody else. (US-East-1 comes to mind.)
Why would anyone voluntarily isolate themselves from the interconnected web, separated by positively glacial light-minutes, hours, or... gasp... centuries!
If the speed of light is an insurmountable barrier, then nobody in their right mind[1] would cut themselves off like this, from everything and everyone else.
Even huge "generational ships" would be like... a small rural country town compared to a glittering, vibrant city. No matter how much static information you crammed into its computers, no matter how much entertainment you brought with you, it would be less than that available on the home planet.
It's simple incentives: Why would anyone choose solipsism and isolation, at huge cost and risk, for effectively zero upside!?
Space is not the wild west. There are no prairies, no fertile lands, no rivers to fish. Certainly not in the relative sense compared to the towering cultural edifice that a multi-million-year-old civilisation could build up on their home planet.
Imagine being an artist, or a performer working at some cultural centre of the world like Broadway moving into the middle of totally empty desert.
"Woo! Isolation! No crowds! No fellow performers! No money! Yay! Finally!" -- said nobody ever.
[1] The corollary is that any members of a species willing to head out into the vast cold uncaring abyss of deep space are insane to a significant degree. Space is filled by crazy, dangerous aliens. The sane ones stayed at home!