The Age of the Universe

Run the "Hubble Movie" backwards:

Distance between any 2 galaxies at the present day:

distance = speed x time (the standard formula)

speed = H0 x distance (Hubble's Law)

Substitute Hubble's Law in to the standard formula:

distance = H0 x distance x time

Cancel factors of distance and rearrange:

time = 1 / H0

The time above is the time it would have taken the galaxies to reach their current separation, having started from being on top of each other and is an estimate of the age of the universe that is known as the Hubble Age.

Current best measurements of H0 give a value of 71 km/s/Mpc, which translates into a Hubble Age of 13.8 billion years, which agrees reasonably well with the estimated ages of the oldest stars in the universe.

On to The Cosmological Redshift or back to start.