Question

How fast is the universe expanding in miles per hour?

Answer 1

1.166681 E`-`10 mile/hour/mile = 1.166681 E`-`10 km/hour/km.
Inversely, this is 1 in 1 / (Hubble constant) = 1 in 8571.323 million / h, nearly..

Explanation:

The expansion rate is the Hubble constant 72 km/sec/mega parsec.
1 parsec = 206264.8 AU; 1 AU = 149597870.7 km. 1 hour is 3600 s.
The dimension(s) of Hubble constant is [1/T]. The given answer is valid for any unit of distance.For example, 1.166681 E`-`10 AU/hour/AU is valid.
Also, this is 1 in 1 / (Hubble constant) = 1 in 1/1.166681 E`-`10
= 1 in 8571.323 million / h, nearly.
Important note: This ratio is independent of the choice of the (large or small) unit of distance. .
Per year, the rate is 1 in 977,7764 thousands.