Redshift and Distance in the Expanding Distance! Isn’t This Interesting.

Imagine the ultimate version of a toy Universe: it’s expanding, it’s full of material, and through it all, there’s one photon ⁠— or quantum of light ⁠— that we keep track of and forbid from interacting with any other particle. The photon, at any given time, will have all the properties you expect a quantum … Continue reading “Redshift and Distance in the Expanding Distance! Isn’t This Interesting.”