In the 1920s, Hubble first noted that the further a galaxy was from
us, the faster it was moving away from us. This is in ALL DIRECTIONS.
The "Hubble Law" suggested an expanding universe. Unfortunately, Hubble got the "Hubble Constant" wrong. He determined the value to be closer to 500 km/s per Mpc (That is 500 km/s for every Mpc).
The Age of the Universe from Hubble's Law
Consider this.. you tell your friends you've been traveling 40 miles per hour for the last 80 miles. So, when did you leave?
You know to divide 80 miles / 40 miles per hour.. giving you 2 hours.
Hubble said the Universe was expanding at 500 km/s for every
1 Mpc (1 Mpc = 3 x 1019 km and 3 x 107
seconds = 1 year).
SO: 3 x 1019 km / 500 km per second.. gives you
6 x 1016 seconds.
Expansion of the universe began 2 x 109 yrs ago! (2
billion yrs) WRONG!
They KNEW the earth and stars were more than several billion years old. Many people bought into a STEADY STATE universe because Hubble's Constant didn't give the right age! The Hubble Constant is known today to be about 70 km/s/Mpc, giving an age of 15 Billion Years (in agreement with the oldest known stars).