Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The Fermi paradox revisited: Technosignatures and the contact era

arxiv.org

Post reply on HN
Print view View original

71–80 of 353 posts

Re: The Fermi paradox revisited: Technosignatures and the contact era

#71

Post by PaulHoule »

maerF0x0 wrote: post #52
PaulHoule wrote: post #29

Earlier quoted context omitted.

An old NTSC video signal has a clear periodic structure. Simply counting lines is going to reveal a lot about the structure and if anyone gets the idea of plotting lines they will figure out how to decode it. An efficient digital signal is going to maximize the use of bandwidth if it looks like white noise. That said, a signal like that needs a carefully calibrated receiver, so part of the signal in time-frequency sp…

Makes me wonder if alien life will actually not find our messages simply because we're using such "ancient" techniques. Perhaps they invented a TV like object and used a NTSC like signal, but like 100k years ago and no one in their race knows to look for our old signals. Maybe our comms look like hieroglyphics to them ?

Periodicity is a clear signal that is useful for natural objects like pulsars. I think it would be very clear that analog videos are periodic at the line level and periodic at the frame level. If somebody gets the idea of plotting signals on a grid they will get a sequence of frames. Even creature that don’t see the way we do might develop some kind of raster basted signal processing.

On top of that TV signals would have additional periodicity because the transmitters will be hidden behind the Earth once every 24 hours.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#72

Post by molticrystal »

If you like thinking about the Fermi Paradox, a series that might be enjoyable is the Universe Today's Beyond Fermi's Paradox [0] , it is about 17 articles on different aspects of the problem along with links to papers and essays to make it easy to go deep into a topic.

[0] https://www.universetoday.com/?s=%22Beyond+%22Fermi%27s+Para...

Re: The Fermi paradox revisited: Technosignatures and the contact era

#73

Post by Hizonner »

YurgenJurgensen wrote: post #70
Hizonner wrote: post #65

Earlier quoted context omitted.

> if you don't build a self-replicating hegemonic swarm object, someone else will Why do I care?

If you've achieved enlightenment and freedom from all desire, then it's a bit weird that you're posting on Internet forums. If not, presumably you'd quite like to not be turned into a paperclip.

Hey, if they can't build a swarm that does something more fun than that, why would I think I could? I mean, my own swarm is subject to value drift and may also clip me.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#74

Post by yourapostasy »

spuz wrote: post #44

This paper seems to explore a question I've had for a while which is: What is the maximum distance an Alien civilisation could eventually detect life signatures from Earth assuming their detection technology matches ours? I know that our current radio signals extend 100 light years or so but at which distance could these eventually be detected? I ask because I've read that in order for the SETI program to make a dete…

Our electromagnetic shell drops below the noise floor around 15 light years out for say 5 MW military radars. For coherent signal decoding into carrier wave and payload waveforms as opposed to being able to point to a signal and say, yep that's not natural, probably around 5 light years out. Some discussion here [1] to get you started.

Even assuming super duper alien technology that violates what we know of the physics of signals transmission that can pick up the faintest earliest human radio signals, our 200 light year shell is insignificantly sized against the backdrop of the galaxy at large [2].

Yes, if someone out there is broadcasting on radio frequencies, it would be the galactic equivalent of The Russian Woodpecker [3]. That's possibly a Kardashev Type II or at least a very high like 0.90 Type I level technological civilization accomplishment to put out artificial radio frequencies on the scale of naturally-produced ones.

There is lots of discussion on ideal frequencies to broadcast upon and look for [4]. There is even a discussion familiar to IT data protection folks that is the interstellar equivalent of a station wagon filled to the brim with tape hurtling down the freeway [5].

But the gist is we'd do better to reconfigure our economic north star upon moving the metric ass-tons of humans off Earth into habitats and working out how to move us around space faster and faster, than waiting for ET to visit us.

[1] https://www.quora.com/Radio-and-other-signals-have-been-leak...

[2] https://www.popularmechanics.com/space/news/a27934/galaxy-ma...

[3] https://en.wikipedia.org/wiki/Duga_radar

[4] https://www.cambridge.org/core/journals/international-journa...

[5] https://en.wikipedia.org/wiki/Interstellar_communication

Re: The Fermi paradox revisited: Technosignatures and the contact era

#75

Post by phreeza »

spuz wrote: post #44

This paper seems to explore a question I've had for a while which is: What is the maximum distance an Alien civilisation could eventually detect life signatures from Earth assuming their detection technology matches ours? I know that our current radio signals extend 100 light years or so but at which distance could these eventually be detected? I ask because I've read that in order for the SETI program to make a dete…

May be true for radio signals, with the possible exception of OTH radar? But there are other technosignatures such as atmospheric composition that they may also be able to detect at substantial distances I think.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#76

Post by YurgenJurgensen »

bnralt wrote: post #63
tsimionescu wrote: post #55

Earlier quoted context omitted.

I am quite certain that using all of the iron in a single planet's core is well beyond the difficulty of building a self-replicating probe (which itself is well beyond our technical capabilities). Not to mention, such probes are unlikely to be build able from a single metal, and some metals used for advanced electronics are significantly rarer than iron.

If you want to restrict yourself to the earth's crust, that'd still be ~5,000,000,000,000 kilos of iron you could use per star, or 1,500,000 Saturn V's. And that's just using one planet. Sure, there are rarer metals. But I'm not seeing evidence that the solar system wouldn't have enough of them, and mass mining and manufacturing seems like an far easier way to handle them than individual probes (the probe would have…

The fact that you're talking about Saturn Vs and landing on planets and taking off again shows that you're considering the wrong paradigm entirely. If you're landing on planets you're already doing it wrong. Atmosphere and gravity wells are the enemy. Remember, even the non-self-replicating probe still needs to be self-repairing, since in your scenario it has to last for probably a million years' worth of radiation and micrometeorite damage. A million years' worth of spare parts is probably a much bigger investment than some automated manufacturing.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#77

Post by YurgenJurgensen »

Hizonner wrote: post #73
YurgenJurgensen wrote: post #70

Earlier quoted context omitted.

If you've achieved enlightenment and freedom from all desire, then it's a bit weird that you're posting on Internet forums. If not, presumably you'd quite like to not be turned into a paperclip.

Hey, if they can't build a swarm that does something more fun than that, why would I think I could? I mean, my own swarm is subject to value drift and may also clip me.

It doesn't matter that you're unimaginative, only that not everyone is as unimaginative as you.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#78

Post by izzydata »

Hizonner wrote: post #61
izzydata wrote: post #54

Earlier quoted context omitted.

If you are talking about a dark forest then it is more opf the idea that any other sufficiently advanced civilization would simply destroy you as soon as you are known to them rather than attempting to consume any potential resources you have as that isn't economical. The most economical thing could be as simple as sending a small object at light speed through your sun to cause a supernova. This eliminates you as a p…

While your main point stands, I doubt that crashing even a moderately sized planetoid into a star at any achievable speed would do much to that star. It definitely wouldn't cause a normal supernova. You might be able to produce some nasty radiation/ionized crap/relativistic debris that would be unpleasant for that greenish scum clinging to some of the planets, but it'd be a really expensive way to do even that. Sure,…

At least as far as our current understanding of physics it is probably not possible to accelerate an object to the actual speed of light, but who knows if there is some kind of universe hack that we don't know of.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#79

Post by bnralt »

YurgenJurgensen wrote: post #76
bnralt wrote: post #63

Earlier quoted context omitted.

If you want to restrict yourself to the earth's crust, that'd still be ~5,000,000,000,000 kilos of iron you could use per star, or 1,500,000 Saturn V's. And that's just using one planet. Sure, there are rarer metals. But I'm not seeing evidence that the solar system wouldn't have enough of them, and mass mining and manufacturing seems like an far easier way to handle them than individual probes (the probe would have…

The fact that you're talking about Saturn Vs and landing on planets and taking off again shows that you're considering the wrong paradigm entirely. If you're landing on planets you're already doing it wrong. Atmosphere and gravity wells are the enemy. Remember, even the non-self-replicating probe still needs to be self-repairing, since in your scenario it has to last for probably a million years' worth of radiation a…

I brought up Saturn V's to give people a sense of the mass we're talking about, not because I thought the probes would be actual Saturn V's (and I don't think we'll be sending 1.5 million of them to a single star).

As I said, the reason I talked about landing on planets is because you mentioned rare metals, and I don't know how _reliably_ they could be found if you're only looking at asteroids. But maybe that's not an issue.

Re: The Fermi paradox revisited: Technosignatures and the contact era

#80

Post by _tom_ »

The Fermi paradox assumes that "intelligent" is one threshold, and we are beyond it.

We couldn't communicate with the most advanced primates from a million years ago. A civilization a million years past ours would be unlikely to want to talk to us. The average star in our galaxy is a billion years older than our sun.

You can only communicate with civilizations near your level, which are inherently much rarer.

We aren't old/developed enough to be interesting to talk to.

Post reply on HN