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3 There is big cost or downside to galaxy-wide expansion that we don't get and that limits expansion, like travelling interstellar distances being far harder th

3 There is big cost or downside to galaxy-wide expansion that we don't get and that limits expansion, like travelling interstellar distances being far harder than we imagine in practice. 4 We are weird in that we want to expand like this, but others don't, similar to how chimps appear to be well able to express themselves in sign language, but appear to simply lack any urge to do so. Similar to your #2. 5 There simply isn't a compelling reason to expand galaxy-wide by the time you can. Reproduction must be stabilized in some way if mortality is taken out of the equation, which will probably happen earlier, a sufficiently advanced understanding of cosmology and physics might conclude there isn't any danger that can't be managed or that spreading out over a few lightyears wouldn't guard against sufficiently well. Getting rid of evolutionarily helpful urges that become a burden in a post-evolution world might be a filter by itself, so this is similar to your #2 in that they're different in a way we can't easily conceive. 6 Once you can make any existence you want happen (by some kind of unimaginably advanced VR) and have tech keep everyone safe and alive indefinitely, the actual universe might start to seem underwhelming. Better to live out the millennia in a perfectly convincing hedonistic metaverse. I could see that happen to us, come to think of it.

jandrese 4y ago
> 3 There is big cost or downside to galaxy-wide expansion that we don't get and that limits expansion, like travelling interstellar distances being far harder than we imagine in practice. This is my thought. Without FTL travel you have to go the slow way. Probably much less than C thanks to the rocket equation. But in order to do this you need to build a spacecraft capable of surviving for centuries or longer with absolutely no outside support, not even solar power. But if you can build that you have effectively unlimited space in your own solar system. Why bothering to travel to a different solar system at that point? Maybe if you have used up literally all of the resources in your current solar system, but that's a multi-billion year process. So you might only need to make the trip once or twice in the current age of the universe. But even that seems less likely than just developing really good recycling systems. So the solution to the Fermi paradox is that by the time you have the tech to travel between solar systems there is no longer any need to do so.
- bsder 4y ago
  > So the solution to the Fermi paradox is that by the time you have the tech to travel between solar systems there is no longer any need to do so. I don't buy that. Human society ALWAYS has a few malcontents who simply want to do something "because it's there." I find it hard to believe that any evolutionarily successful race wouldn't also have some individuals with the same kind of drive.
  - jandrese 4y ago
    It's kind of like asking why we don't have any driven individuals who do a solo swim from Hammerfest to Port Lockroy. Even with a high tech society the resource requirements are extreme. It is likely to require significant collective effort to build a ship and especially to fuel it. Thousands of metric tons of fuel at a minimum if you want to reach anywhere in only a few lifetimes, probably millions.

jandrese 4y ago

> 3 There is big cost or downside to galaxy-wide expansion that we don't get and that limits expansion, like travelling interstellar distances being far harder than we imagine in practice. This is my thought. Without FTL travel you have to go the slow way. Probably much less than C thanks to the rocket equation. But in order to do this you need to build a spacecraft capable of surviving for centuries or longer with absolutely no outside support, not even solar power. But if you can build that you have effectively unlimited space in your own solar system. Why bothering to travel to a different solar system at that point? Maybe if you have used up literally all of the resources in your current solar system, but that's a multi-billion year process. So you might only need to make the trip once or twice in the current age of the universe. But even that seems less likely than just developing really good recycling systems. So the solution to the Fermi paradox is that by the time you have the tech to travel between solar systems there is no longer any need to do so.

bsder 4y ago
> So the solution to the Fermi paradox is that by the time you have the tech to travel between solar systems there is no longer any need to do so. I don't buy that. Human society ALWAYS has a few malcontents who simply want to do something "because it's there." I find it hard to believe that any evolutionarily successful race wouldn't also have some individuals with the same kind of drive.
- jandrese 4y ago
  It's kind of like asking why we don't have any driven individuals who do a solo swim from Hammerfest to Port Lockroy. Even with a high tech society the resource requirements are extreme. It is likely to require significant collective effort to build a ship and especially to fuel it. Thousands of metric tons of fuel at a minimum if you want to reach anywhere in only a few lifetimes, probably millions.