[leobuskin]

If I understand correctly, time spent within this interstellar ship reference frame would be significantly less than 75k years. And at 1c speed, 48 years on Earth would be ~2 years of "flight" for the passengers, correct me if I'm wrong.

[creesch]

You are not wrong, but it still wouldn't make a whole lot of difference. First of all with any technology we currently have, including hypothetical proposals, we can't even get close to 1c. The best we can do, and this assumes purely hypothetical unproven ideas, is accelerate to a fraction of the speed of light. Acceleration itself will take up a significant amount of time and even then we are nowhere near the speed of light. Project Orion would in theory be able to do 3% to 10% of the speed of light. That's about the only proposed propulsion we actually have the technology for in the sense that we might be able to build it this decade.

So let's be optimistic and assume we can reach 10% of c (unlikely), that is 10 years for one light year, meaning that it takes about five centuries. Practically speaking 10% of c is unlikely, it takes about a month to accelerate to those speeds you'd need an insane amount of mass in the form of bombs to explode to just get up to speed. Which is why 3% is more "realistic". Oh, did I mention that there is no realistic way to slow down either? In theory it is just detonating the same amount of bombs in front of the craft, but in order to take that mass on your journey you'd need a lot more mass to get up to speed and the numbers get silly rather quickly.

So "realistically" at 3% of c we are talking about roughly 1500 years to just speed past our target.

Also, the original remark was about sending probes, not humans. But at 3% or 10% of c time dilation isn't much of a factor either so you'd need a generational craft if you want to send people.

Again, space is big, really big.

[eaenki]

Man, that’s not how intelligence works. Eventually if a civilization doesn’t blow itself up, it will achieve anything, and it’s not incremental steps. Speed has never been incremental steps. in 1810 you would’ve been thinking about faster horses or some shit like that. Def not rockets. OP said hundreds of years. In hundreds of years from now our rulers will definitely have that kind of tech, whatever tech it is.

[bluGill]

Often technology is approaching an asymptotic limit that it will not go beyond. Know about a hand waving will change the laws of physics. There's every reason to believe that the speed of light is a maximum that we will never be able to choose because it requires infinite energy. While it is true we don't know everything, and there are certainly parts of it we don't know, the things we do know will have to obey and predict the things that we currently do know to be true. The laws of relativity, although annoying, are very good at describing things. If anything replaces relativity, it's going to replace it while still predicting exactly the same things that relatively does that we have verified. That doesn't leave much room for a theory that might and faster travel.

[creesch]

> Def not rockets. OP said hundreds of years.

Yeah to reach it with current tech. No shifting goal posts, thank you very much.

> In hundreds of years from now our rulers will definitely have that kind of tech, whatever tech it is.

Also, I should point out that technological progress isn't linear and guaranteed. Also, "our rulers" what ...?