Hi Gary
This particular line really stopped me in my tracks:
"While the Hubble Constant is constant everywhere in space at a given time, it is not constant in time. So, when we are comparing the Hubble Constants that come out of various techniques, we are comparing the early universe (using distant observations) vs. the late, more modern part of the universe (using local, nearby observations).”
When taking Physics classes at school we performed several experiments that involved measure various (less esoteric) constants and I was always puzzled by how many "Constants" there were.
In an abstract sense, if some "thing" is "Constant", meaning non-changing, immutable, ever the same, etc. then "it" should not have a "beginning".
Otherwise when it "started" it must have changed from "not existing" to "now existing", which is a "change", so it cannot be a "Constant".
Needless to say this is adult life contemplation, not from my school boy days.
Cheers
Dennis