5 ms·

Because we went from beating sticks together to manned spaceflight in less than 1x10^4 years. Isn't it fair to extrapolate that to inter-stellar travel in 1x10

Because we went from beating sticks together to manned spaceflight in less than 1x10^4 years. Isn't it fair to extrapolate that to inter-stellar travel in 1x10^6 years?

irrational 7y ago
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.
- scrumper 7y ago
  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?
  - manicdee 7y ago
    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.
  - irrational 7y ago
    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.
    - krapp 7y ago
      >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.
    - scrumper 7y ago
      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!
  - baja_blast 7y ago
    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.
- kangnkodos 7y ago
  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.
  - 0xffff2 7y ago
    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.
  - Andrex 7y ago
    Because that's how you get Neon Genesis Evangelion. https://wiki.evageeks.org/First_Ancestral_Race 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.)
ogre_codes 7y ago
It's not even clear we'll be around to argue about this in another 1,000 years, let alone another 100,000. It seems like our ability to destroy things is outstripping our ability to fix them. Part of the Fermi paradox they skipped in this article is the idea of a Great Filter which prevents life from evolving or creating a space faring culture. The assumption is that we're past the filtering event, but it's entirely possible that we haven't reached it and in some unknown future our race will cease to exist. Imagine a technology which would allow a single insane being to destroy the entire planet, or at least all intelligent life. We're not too far off from that point now if you consider modern political power. If that point of technological advancement is inevitably discovered prior to the technology required to become a space-faring race. The idea of an individual or small team of scientists creating a world-threatening virus or triggering nuclear war is not that far outside our current state of affairs. Interstellar space travel is likely at least 100 years in the future.
jcranmer 7y ago
Why should interstellar travel be realizable? If FTL is not possible--and there is no reason to think it is--then interstellar travel requires a craft that is capable of maintaining a colony-sized group of people for centuries or millennia, industrial bootstrap capabilities, repairs for everything in the meanwhile, food and energy for the trip, and the fuel reserves to slow it down at the end and land. The size that such a craft needs to be plausible suggests that the fuel amount in question will probably be best measured in something like "years of total Earth natural gas production."

Because we went from beating sticks together to manned spaceflight in less than 1x10^4 years. Isn't it fair to extrapolate that to inter-stellar travel in 1x10^6 years?

irrational 7y ago

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.

scrumper 7y ago
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?
- manicdee 7y ago
  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.
- irrational 7y ago
  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.
  - krapp 7y ago
    >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.
  - scrumper 7y ago
    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!
- baja_blast 7y ago
  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.
kangnkodos 7y ago
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.
- 0xffff2 7y ago
  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.
- Andrex 7y ago
  Because that's how you get Neon Genesis Evangelion. https://wiki.evageeks.org/First_Ancestral_Race 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.)

ogre_codes 7y ago

It's not even clear we'll be around to argue about this in another 1,000 years, let alone another 100,000. It seems like our ability to destroy things is outstripping our ability to fix them. Part of the Fermi paradox they skipped in this article is the idea of a Great Filter which prevents life from evolving or creating a space faring culture. The assumption is that we're past the filtering event, but it's entirely possible that we haven't reached it and in some unknown future our race will cease to exist. Imagine a technology which would allow a single insane being to destroy the entire planet, or at least all intelligent life. We're not too far off from that point now if you consider modern political power. If that point of technological advancement is inevitably discovered prior to the technology required to become a space-faring race. The idea of an individual or small team of scientists creating a world-threatening virus or triggering nuclear war is not that far outside our current state of affairs. Interstellar space travel is likely at least 100 years in the future.

jcranmer 7y ago

Why should interstellar travel be realizable? If FTL is not possible--and there is no reason to think it is--then interstellar travel requires a craft that is capable of maintaining a colony-sized group of people for centuries or millennia, industrial bootstrap capabilities, repairs for everything in the meanwhile, food and energy for the trip, and the fuel reserves to slow it down at the end and land. The size that such a craft needs to be plausible suggests that the fuel amount in question will probably be best measured in something like "years of total Earth natural gas production."