Time is relative, and passing through space at different velocities warps time. Peering deeper into space is also peering further into time. Every physics equation and observation must account for all four dimensions. Since they are so intricately tied together, and dependent upon each other, astro-physicists speak of Space-Time.

All we know, all we can ever know, the entire universe is contained within Space-Time. Anything speculatively beyond that is outside of our existence.