Reading the Wikipedia article makes my head spin! Somehow the figure https://en.m.wikipedia.org/wiki/File:Observable_universe_logarithmic_illustration.png doesn't seem quite right. I don't understand how the CMBR doesn't define the edge of the universe. If we can see the CMBR that happened near the beginning of the expansion, how can there be objects beyond that we can't see? It seems the edge defined by the CMBR is within the theoretically observable sphere, therefore we can see the whole universe? Sorry in advance for the dumb questions. Perhaps someone could suggest some better reading on the topic. Thanks.