Caleb Scharf is the director of the Columbia Astrobiology Center. He writes the Life, Unbounded blog for Scientific American; has written for New Scientist, Science, and Nature, among other publications; and has served as a consultant for the Discovery Channel, the Science Channel, the New York Times, and more. Scharf the author of Gravity's Engines: How Bubble-Blowing Black Holes Rule Galaxies, Stars, and Life in the Cosmos (Scientific American/FSG), and Extrasolar Planets and Astrobiology, winner of the 2011 Chambliss Astronomical Writing Award from the American Astronomical Society.