Good questions. You got the right long line. The normal number line, the "real line" can be thought of as taking a half-open unit interval [0,1) and putting one

Good questions. You got the right long line. The normal number line, the "real line" can be thought of as taking a half-open unit interval [0,1) and putting one at each integer to "fill in the gaps". This is already very long. If you did the same thing, but stuck together each point on the real line, then you'd get the long line. Cosmic fluid is a model of the universe as a fluid, like an ideal gas or something. The phase space is is the space of all the possible states it can get in to (shape, flow, pressure etc.) You may call this state space depending on how you think about spacetime. See e.g. https://en.m.wikipedia.org/wiki/Equation_of_state_(cosmology) https://en.m.wikipedia.org/wiki/Equation_of_state_(cosmology... . xkcd: 435, 794, probably others