The Fermi paradox revisited: Technosignatures and the contact era

It’s the same problem as surviving cryonic suspension. If we can do that we could go to the stars.

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 and power, because otherwise the reason we're free to exist is because species like us always wipe themselves out before they spread.

If we're talking about galactic distances and timescales I don't see why we couldn't safely assume enough technological advancement for either aliens or humans to modify their own biology to the point where centuries would be a small fraction of your total lifespan. I think the bigger question is why any significant number of people would travel to more than a few star systems if you had to do it slowly. If the system is uninhabited then you would be isolating yourself from the rest of society for a long time. If it's inhabited then you would have the excitement of discovery and contact but it would still be difficult being separated from your own civilization and you would want to return at some point even if just to share what you've learnt.

How many people today travel to places that are completely uninhabited and have no infrastructure in place for getting there? I'm talking end of the road, getting on a bush plane and landing in the middle of an open field kind of isolated. How long do they stay? Same for contacting the few remaining hunter gatherers on the planet. What if those trips took thousands of years instead of a few weeks?

I think there's a big stretch of time for the development of any technological civilization where they spend most of their effort on developing their own solar system and only send small flyby probes to their nearest neighbours. After that there may be an even longer period during which they colonize those near by stars but each colony likely takes an extremely long time to fully develop. The civilization may send out automated probes to look and listen and maybe the occasional explorer or anthropologist but I doubt there are any galaxy conquering civilizations out there.

So I think I do agree that if anything visits us it is likely to be an automated probe. Bracewell probes would be well suited to any chatty civilization that is seeking contact. Von Neumann probes are more suited to brute force exploration.

This is all assuming that the speed of light is the fastest you can travel and communicate. If it isn't, then I'd say all bets are off.

Good grief, did anyone read the paper, or are you all just sprouting your own personal Fermi paradox theories?

> The basic assumption of this work is the hypothesis that alien civilizations do not bother to explore merely biotic planets, so that the radiosphere criterion becomes the main trigger for alien civilizations to send interstellar probes

The tldr; in this work is that they assume there’s a finite (short) duration during which civilisation are “noisy” and given that our “noise” is currently at most ~100 light years from us, no one has noticed us and bothered to send a probe or direct a signal at us.

I mean, it’s an interesting (not, in my view, novel) take, in that it posits that every civilisation has a finite spherical band in which they are “detectable” by radio emission before they go to “quiet” technology like fibre optic; and you’d have to be specifically looking at just the right time while you were in that (supposedly) brief band.

…but, it really doesn’t to give any thought to spectral analysis / why a “quiet” civilisation would be undetectable on the basis of generating complex / unusual chemical signatures in their atmospheres, and why we don’t see anything like that out there.

It’s really, just restricted to the consideration of radio broadcast and, unsurprisingly, given the restrictions, makes it implausible anyone would notice us / we would happen to be looking while anyone was “noisy” and visible in the radio spectrum.

Eh. Did I miss anything interesting in there? It doesn’t seem particularly novel.