The observable universe

[I suggest reading my earlier post, The Big Bang, before this one.] The observable universe (OU) is the part of the universe that we can, at least in principle, observe, from a designated vantage point at a given place and time. This post is my attempt to figure out in more detail exactly what the OU …

The Big Bang

In cosmology, the term the Big Bang has several subtly different meanings. It means the moment in time, it means the "explosion" event, and it means the all the events and states of the early universe. How early is early? Could be lots of things. Maybe just the first fraction of a second, maybe the …