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The Fermi paradox revisited: Technosignatures and the contact era

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

#101

Post by denton-scratch »

actionfromafar wrote: post #66
1970-01-01 wrote: post #25

Until SETI locates something like a pulsar braking and accelerating to signal prime numbers we're really really really unlikely to stumble onto more life. Space is just too big.

I think it can be done cheaper than that, and with technology we have access to. Detonate a handful of large hydrogen bombs in deep space, set apart by minutes. Say hello to our fellow Aliens.

Luckily, the aliens are wearing Swiss wristwatches, they know how long a minute is, and so are able to notice that the intervals are a prime number of minutes :-)

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

#102

Post by superposeur »

In my opinion, the excitement occasioned by the discovery of so many exoplanets has clouded our collective judgement on the Fermi Paradox, leading the overwhelmingly most probable resolution to be underemphasized.

Namely: there is no life out there. Not due to baroque mechanisms such as techno-self-destruction but just due to its sheer unlikeliness. As large as the number of stars in the observable universe is (let’s say 10^24?), the space of combinatoric possibilities that must be threaded for the sustained chain reaction of life to occur is probably that much vaster. The so-called Drake equation is not useful since multiple terms have error bars that are not even estimable.

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

#104

Post by joshuahedlund »

steveBK123 wrote: post #94
cartercwchen wrote: post #24

I prefer the Dark Forest interpretation of the Fermi Paradox: https://en.wikipedia.org/wiki/Dark_forest_hypothesis

The author raises an interesting question in his notes - human nations & races have for much of human history distrusted each other & gone to war. And yet we broadcast our location and welcome out into the cosmos assuming that alien species will be benign and friendly!

IMO that fact is actually a pretty strong reason to doubt the dark forest hypothesis as a serious explanation for the lack of observable aliens. If we've broadcast ourselves to each other for thousands of years and now even to the universe, why should we expect that every single other civilization out there is consistently doing the exact opposite?

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

#105

Post by rvnx »

russdill wrote: post #90
eloff wrote: post #37

Earlier quoted context omitted.

But is it? We can detect things about the chemical makeup of the atmospheres of extra solar planets. Our own atmosphere is broadcasting the likely presence of life, plus near certainty of industrial civilization. We could detect that up to some distance with our technology. What could advanced aliens detect? What if they used gravitational lensing to magnify the signal? We can’t rule it out. Let’s hope the dark fores…

Our signal for oxygen and other bio-signatures is so much stronger than the signals we have been sending recently and it's been going out for...quite some time.

Maybe they found Earth already and they just find it boring: "yet another planet likely filled with idiots"

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

#106

Post by Izkata »

marcosdumay wrote: post #43
causality0 wrote: post #36

The universe we find ourselves in isn't very compatible with a species like our surviving for an extended period. If humans exist for millions of years we're going to either spread out to fill the galaxy or our machines will. The fact earth was free to develop us means that no other species like us existed long enough to beat us to it. We ought to hope that's because species find some other priority besides expansion…

> because otherwise the reason we're free to exist is because species like us always wipe themselves out before they spread That's a complete non-sequitur. There can be plenty of reasons for a species like us never appearing on the first place, and they are way more reasonable than postulating that life like us always destroy itself.

> There can be plenty of reasons for a species like us never appearing on the first place

We already have an example of it, too: Look how long the dinosaurs were around compared to humans.

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

#107

Post by denton-scratch »

fawadasaurus wrote: post #67
1970-01-01 wrote: post #25

Until SETI locates something like a pulsar braking and accelerating to signal prime numbers we're really really really unlikely to stumble onto more life. Space is just too big.

Agreed. I read somewhere that if you pick a random direction and fly through space, you have a 0% chance to ever hit anything. That is how big and empty the universe is.

Well, you're almost certain to hit a hydrogen atom within a meter of travel in deep space. Larger objects will be less common, no doubt.

> That is how big and empty the universe is.

Indeed. The corrollary is that there's an awful lot of space to travel through in search of something to hit.

Regarding that 0%: I don't think it's possible for you to travel through space fast enough to catch up with the expansion of the Universe. It follows that your search for something to hit goes on forever, and the chance of eventually hitting something must be 100%.

Whoah! Not so fast, Denton! As you are travelling looking for something to hit, the Universe is expanding, and the distance between galaxies is growing. So the longer you travel, the less likely you are to find something to crash into.

I don't know how to work out the sums. I don't know how to multiply a 0% chance by a 100% chance. Or rather, I do; it just gives an answer that I don't like intuitively. It should be a 0% chance; I guess it probably is.

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

#108

Post by georgeg23 »

superposeur wrote: post #102

In my opinion, the excitement occasioned by the discovery of so many exoplanets has clouded our collective judgement on the Fermi Paradox, leading the overwhelmingly most probable resolution to be underemphasized. Namely: there is no life out there. Not due to baroque mechanisms such as techno-self-destruction but just due to its sheer unlikeliness. As large as the number of stars in the observable universe is (let’s…

I don't think people realize how quickly EM radiation falls off with distance, and how large the scale of "transmitters" would need be before we could detect.

Today we can finally, barely detect massive planets occluding suns, and we can only do this in our neighborhood of this galaxy.

Modulated communication from a source not at planetary scale is currently impossible for us to detect.

We need something much much bigger than the Arecibo telescope (RIP).

Arrays of coherent antennas can achieve gains equal to their total aperture, but spacing them out far apart does not help for communication receiver gain G/T. That technique only gives better angular resolution for imaging.

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

#109

Post by topaz0 »

denton-scratch wrote: post #101
actionfromafar wrote: post #66

Earlier quoted context omitted.

I think it can be done cheaper than that, and with technology we have access to. Detonate a handful of large hydrogen bombs in deep space, set apart by minutes. Say hello to our fellow Aliens.

Luckily, the aliens are wearing Swiss wristwatches, they know how long a minute is, and so are able to notice that the intervals are a prime number of minutes :-)

If the intervals are relatively prime, it wouldn't take much to work out what the intended time unit was.

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

#110

Post by Izkata »

thereddaikon wrote: post #92
AlanSE wrote: post #50

Earlier quoted context omitted.

That argument seems to violate the basic rules of exponentials. If an advanced species did settle on an stasis, then that will only last until some subset of the population decides to go beyond the stasis. Particularly for a space-faring civilization, the time scales and resources are so fast, that any multiplication factor beyond unity will eventually go bananas. Any individuals with the prerogative to multiply will…

I think the answer is pretty obvious, we are the precursor species. Or it could be any number of things other than nobody out there. For example, advanced life could be out there but it might be rare enough that you only end up with a handful of space capable civilizations at any one time. The milky way is a big place. If we assume that ultimately there isn't a clever way around the speed of light then two civilizati…

Maybe no one comes here because Earth is deep inside the Veil of Madness...

https://creepypasta.fandom.com/wiki/Mankind

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