But Why explores the Big Bang, earth, stars and black holes in this call-in episode that aired live on Vermont Public Radio. Astronomer John O'Meara tackles the big bang, the origins of the universe and how we know humans landed on the moon. Plus, why is the earth round? What is space made out of? How are stars formed? Why do the stars shine so bright? What's beyond space? How long does it take to get to outer space? Will humans ever be able to go to Mars?