On Tue, 1 Jan 2019 00:19:24 -0800 (PST), RichA
wrote:

No, we are on the surface. The surface is "now". The center is t=0
(actually, it is (0,0,0,0), the location of the Big Bang). The past is
inside the sphere, where it is not accessible to us.

If we are to take this literally, then the universe isn't flat, it has no end-point (for us) and building bigger telescopes means little.

I don't follow. Why is there no value in building instruments that
extend how far we can see, in both space and time?