Summary: Today on the Ask An Astronomer Podcast... 1) We listen to the unseeable, the sound of two black holes colliding. 2) Dave K and Dave B delve into the mysterious Dark Energy, which Cosmologists believe fills the entire universe and is why the universe keeps expanding. 3) And we answer a question from a reader about the number of stars in the Milky Way, and how Astronomers use Galaxy Zoo to take a census of the night sky. ...today on the Ask An Astronomer Podcast. Today's podcast is written and produced by David Bernat, Ann Martin, Carl Ferkinhoff, Betsy Adams, Manoilis Papastergis, Laura Spitler, Dan Tamayo, and David Kornriech. You can ask us your own questions by emailing us at 'curious@astro.cornell.edu' (please put 'AAA Podcast' in the title) or leave us a message at our new telephone number: 1-ITHACA-0-SKY (1-484-222-0759).
