[GTP]

This isn't my field, but I see a huge gap between what in the abstract they say it would be feasible for us and what we're currently capable of. I mean, we're able to send space probes around, but self-replicating space probes and Dyson spheres feel on another level. Am I the only one?

[mullingitover]

Life itself could arguably be a Von Neumann probe. It's so good at spreading that it's a problem, when we send probes to other bodies in our own solar system we often sanitize them because we worry life will hitch a ride and start colonizing.

Life on a planet is a lot like a continuous fire, fires often send out embers that start new fires elsewhere.

You send out little packets of life to new places, wait single-digit billions of years (a blink of an eye for the universe, really), boom: new intelligent species with potential to shoot more seeds out into the universe.

[sejje]

Do we have anything that self-replicates physically?

Software, sure. I know 3D printer folks will sometimes 3D print parts for new machines. But nothing that fully replicates itself, right? Especially autonomously.

Maybe we'll see what a moon base can bring us.

[diziet]

Basically all of life is self replicating, physically.

[psychoslave]

I guess the OP meant something that is more flatous for human vanity to feel like a demiurge when at most it would be a tool of cosmos in its experiment.

[GTP]

Yes, but this isn't what the paper is talking about.

[GTP]

Additionally, you also have to consider that a self-replicating space probe should be able to find, retrieve, and process the raw materials needed to build new probes on its own. A 3D printer can print some of its own parts, but with externally-provided material that it isn't able to produce on its own.

[NitpickLawyer]

> what we're currently capable of.

What we're capable of != what we're doing / not doing because of political will. We are technically capable of reaching significant fractions of c with tech from the 1960s. We'll never do that because there's no will to do it, but the tech is there.

Same for self replicating stuff. We could build self-contained factories that build stuff from raw minerals, but we'll likely not do it until there's a will for it. Or need for it.

[TheOtherHobbes]

Political will is part of the Fermi paradox. So are technical reliability and cultural stability.

The idea that you can just build a thing and send out a swarm and (slow) boom - you've colonised the galaxy, and all the adjacent galaxies - is hopelessly naive. To the point I'd call it stupid and silly.

Let's say you have a replicator thing that works. You send them out in swarms.

And then what? Some die, some miss, some are destroyed by accidents.

Some work.

But "a replicator landed and made some more" is not colonisation. Colonisation implies there's some kind of to-and-fro traffic, maybe trade, some kind of information exchange at a minimum.

And that implies the source civilisation has political, technological, and cultural stability, which can survive an incredibly slow diaspora.

Colonisation worked on Earth because it didn't take long to cross the Atlantic by sailing ship. Successful colonisers landed where humans already existed and trade was easy.

It doesn't work on interstellar, never mind intergalactic time scales, because nothing stays stable for that long. Not hardware, software, politics, or culture.

Nor, on slightly longer periods, biology. On much longer periods, geology, and eventually astrophysics, because stars change, and planetary systems aren't unconditionally stable.

So a colonising wave from a unified culture is an incredibly unlikely thing, not at all an obvious necessity.

[GTP]

This would mean bootstrapping current advanced manufacturing technologies to a new planet. You would need so many different tools to do that that I seriously doubt we are currently capable of making it compact enough to be sent into deep space with current technologies. We're currently sending at most small capsules into deep space, my gut tells me that for self-contained factories we would need to send something in the size order of a skyscraper.

[db48x]

Yea, the paper discusses a probe with a mass between 50g and 500kg using a diamondoid data storage medium that holds ~6,250 exabytes per gram. Plenty of room for any blueprints you want to include, up to and including a planet full of humans. If not actually today’s tech, it is but a few years into the future. I’m sure my next computer will have a few hundred grams of that diamondoid storage.

[GTP]

Blueprints are the last of my concerns. What I think will be hard to do is to implement a full supply chain into a single space-travelling factory, including sourcing and refining of raw materials. But, regarding the blueprints, it now occurs to me that our "recipes" are made to work on our planet. Another one may lack some "ingredients" or have atmospheric conditions that could mess with the chemical reactions we use here. So we would need an advanced AI able to adapt production to the environment it finds.

[db48x]

Sourcing and refining materials are just blueprints. Adaptations for other environments are just different blueprints.

But honestly most of the work would be done in vacuum. Skip the planets, build the daughter probes out of asteroids. Most systems should have plenty of easily accessible material even if they don’t have a prominent asteroid belt, even if the probe has to scavenge the system’s oort cloud.