The folks at SciShow teamed up with Google and YouTube to bring us answers to 10 of the most commonly searched questions on the Internet. Today's question? How old is the earth?, or, an even better question: How do we know how old the earth is?

Other questions tackled in SciShow's latest series include How do I get rid of hiccups?

And What is love?

Answers to seven more of the world's most asked questions are still forthcoming. Look for them at SciShow.