Let's say in the year 2000 we launch a ship to some distant part of the galaxy. If the ship travels with a constant 1 g acceleration for like 28 years (accelerating halfway then decelerating), then we can reach as far as Andromeda. The catch being that people of Earth have experienced some millions of years while you and your crew only experienced 28.
It's not currently feasible to communicate faster than the speed of light, and I think this generates some really fun issues. Mainly, that we would have trouble passing resources or information in either direction.
- Not all "societies" in space will have the same technology
- We really can't have the same government or even abide the same laws
- We may also see other events in the cosmos in different orders, as relative simultaneity kicks in.
With all these issues, why would we even try to communicate or cooperate? Are there any special ways we can help each other that closer societies like England and France could not?