Before, During, After the Bang: Part 3

 This is the third in a series leading up to our Zoom meeting Tuesday and beyond.

Distant regions of space in opposite directions of the sky are so far apart that, assuming standard Big Bang expansion, they could never have been in causal contact with each other. This is because the light travel time between them exceeds the age of the universe. Yet the uniformity of the cosmic microwave background temperature tells us that these regions must have been in contact with each other in the past.

How can that be?