We live on a spinning planet. Depending on latitude your individual speed varies from 0 mph at the poles to 1,040 mph (1,674 kph) at the equator. Here at 47 degrees north I'm madly spinning eastward ...

In 1929, astronomer Edwin Hubble published a paper demonstrating that the universe is expanding. It gave rise to the Hubble constant, the number that describes how fast the universe is expanding. But ...