Those timelines don't seem very conservative. 1% sounds like a nice, small number, but 1% of the speed of light is insanely fast. It's about 200 times faster th

Those timelines don't seem very conservative. 1% sounds like a nice, small number, but 1% of the speed of light is insanely fast. It's about 200 times faster than our fastest craft to date. We might envision launching a probe 200 times faster in the future, but a colonization ship would also weigh millions of times more and have to slow down somehow. It's not clear that we'd be able to do that in 10,000 years (or ever) with "shoot stuff out the butt" propulsion, so we'd probably need propulsion based on different physics which may or may not actually exist. We'd definitely need new physics for constant 1g acceleration into relativistic speeds. Maybe we could hitchhike on progressively faster interstellar asteroids or something, but that would void the assumption of having the ability to reach all parts of the galaxy.