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Comment by irrational | Hacker News Reader

No, my gut feeling is that we will never reach another star with humans or a self-replicating probe, so until we do I assume nobody else can/will either.

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Thing that's interesting to me is that we have a number of proposals for how we might reach another star with essentially present-day technology. So even us dumb humans think we could get a robot probe out there. A self-replicating one is much further off of course.

Are you just questioning the Von Neumann machine aspect or the entire feasibility of sending a basic dumb probe out to another star for a fly-by?

There’s a huge technological leap between s tiny laser-propelled fly-by probe and a ship full of humans stopping in that system to settle.

A fly-by doesn't count. Even the Voyager probes will someday fly-by some star. Going to a star and setting up shop (whether a human colony or self-replicating probes) is the only thing that counts in my book.

>Even the Voyager probes will someday fly-by some star.

Not necessarily. I think you underestimate how much of space is space and how little of it is anything else... and that most of that "anything else" is dark matter. Only ~4% of the mass energy of the entire universe is matter.

It seems more likely than not to me that any arbitrary path through interstellar space would never pass near anything larger than a grain of dust.

Oh yeah that's way harder. I'd be OK arguing that we could fling something at Alpha Centauri and have it stop using tech with a very low-risk path from today's state of the art, but even just the 3D printing needed for self-replicating probes (such a printer has to be able to print something exactly as complicated as itself from asteroid material, which is really going to be incredibly hard to do, not to mention energy intensive) is a long, long way off and there's no way I'm going to be able to convince you of the viability of that!

The problem with Von Neumann probes is they couldn't land on a planet like Earth and use it as a launching off point since the escape velocity is too high for a simple probe to produce off of whatever it can extract from the soil. If any landed here it would have eroded away by now, and for all we know it could be all around our solar system and we wouldn't know.

How about a few Voyager-sized probes with a little decision making ability and some DNA? We aim them at the nearest stars which have at least one planet in the habitable zone. It sounds like something which might be possible soon to me.

What makes you think it sounds possible? Unless you're one of a very small number of people in the world who actually work on this kind of thing, "sounds possible" doesn't mean a whole lot. I don't work on the spacecraft, but I do work on the rovers they carry. Based on my limited expertise as someone in an adjacent field, the ability to send any spacecraft to another star on human timescales is not currently possible in any sense whatsoever. The ability to send a "spacecraft" weighing tens of grams to our nearest neighbor might be possible within my lifetime. The ability to get a voyager-sized probe to another star within my lifetime is as far outside the realm of possibility as anything can be.

Because that's how you get Neon Genesis Evangelion.

https://wiki.evageeks.org/First_Ancestral_Race

(Though I suppose two probes would have to accidentally land on the same planet to lead to that outcome.)

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