“We can’t observe the whole universe, so cosmology is not really about the universe. It’s about the observable patch and the assumptions we make about the rest.”
(paraphrasing George Ellis)
We’re in a bounding sphere, with a radius that’s roughly 46.5 billion lightyears, so any observation we make may be true for our local observable range, but there’s no (known) way to know what’s beyond that sphere.
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.
(paraphrasing George Ellis)
We’re in a bounding sphere, with a radius that’s roughly 46.5 billion lightyears, so any observation we make may be true for our local observable range, but there’s no (known) way to know what’s beyond that sphere.