[wtcactus]

Right, but everywhere we look the universe is roughly the same at same distances, so it’s acceptable to extrapolate.

[mr_mitm]

Even if not, it's still worthwhile to explore everything as far as we can see.

[wtcactus]

Relativity restricts us to explore a very tiny sliver of the universe. We can observe, but we will never be able to interact unless Relativity is completely wrong.