This year marks the 400th anniversary of Galileo's use of the first telescope. On this week's show, we reflect on how telescopes have changed our perception of our place in the universe, how small we are in size, space and time. Our guests include Dava Sobel, author of The Planets, Vatican Astronomer Father Chris Corbally, and astronaut Paul Richards. We also discuss how they help astronomers discover new and interesting aspects of the universe, from Earth-like planets to supernova, from black holes to the Big Bang. Guests: Dava Sobe,: Author of Galileo's Daughter, and, more recently, The Planets. Father Chris Corbally, Vice Director of the Vatican Observatory. Paul W. Richards, NASA Astronaut.