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 ...

You can't feel it, but we're rocketing through space at 1.3 million miles per hour. That's because the Earth is orbiting the sun, which is orbiting the center of the galaxy, which is barreling ...