# What is Hubble's Law?

Nov 19, 2015

It states that the universe is expanding.

#### Explanation:

It has two parts:-

1. Every galaxy in the observable universe has a relative velocity away from the Earth(as evidenced by their red shifts) .
2. The farther the galaxy the faster it is moving away from us.

Hubble's Law is given by:
$v = {H}_{0} r$
where:
$v =$ recessional velocity
${H}_{0} =$ Hubble constant
$r =$ distance