On the left side of the animation, numbers indicate the speeds of Earth's rotation, its orbit around the sun, the solar system's orbit around the Milky Way's center, and the galaxy hurtling ...

The Earth is really, really old. Over 4 1/2 billion years old, in fact. How do we begin to comprehend a number that large? It helps to put it on a more fathomable scale. Watch to see where Earth's ...