The aim of the thread is to offer a non-technical concrete way of understanding the standard model. Usual metric, equations, parameters are in the background but the focus here is on unmathematical presentation, indicating how key physical quantities could (ideally!) be measured. When I talk about distances I mostly mean distance between stationary observers--that is stationary wrt the CMB. Stationary is an approximate notion (as most ideas are): the observer's microwave sky is nearly the same temp in all directions. What I mean by the present moment--now--is all the observers for whom the sky has the same temperature. This is my recipe for intuitively understanding standard expansion cosmology, other people can have different ways to go about it. As long as everybody understands that space is just a bunch of distances, then it is perfectly fine to say space expands. The key thing is not to objectify space---think of it as if it were a thing or a material substance. If I suspect there are people in the room who are apt objectify space in their heads, then I try to refrain from saying those exact words "space expands", because it might encourage the idea that it is a thing or material. Instead, I say something that means the same, like "distances increase in a regular pattern." But if I am in the coffee room at the astronomy building with nobody around but some grad students, then I have no compunction about referring to space as expanding because everybody knows it's just a network of geometric relations---basically just a bunch of distances. Saying space expands is just a quick way of stating Hubble Law, which is an empirical observed approximately regular pattern of increase of distances. It's as true as anything ever is in science. It talks about current (now) distances between contemporary stationary observers and it says that on large scale they are currently increasing at a percentage rate of 1/140 of a percent every million years. It's important to mention that the rate changes, it used to be a lot bigger in the past, and it is decreasing asymptotically to about 1/160 percent per million years in the far future. According to the standard model, it will always decrease but at a more and more gradual rate so that it kind of levels out at 1/160 of a percent in the late universe. There is some random variation in the pattern which averages out and it applies to largescale distance outside the range of gravitationally bound systems. It's both empirical and what the standard (Friedmann) model says ought to happen---and it's what is meant by saying space expands. I want to say a bit more about measuring the current distance between stationary observers, but that can wait for another post.