Cosmic collisions have forever shaped the planets in our solar system, sculpting Earth and our Moon. They are still happening right in our neighborhood, as we saw in July 1994 when comet fragments bombarded the surface of Jupiter. What if a collision of that magnitude were to occur on Earth? Would the effect be anywhere near that of the collision that wiped out the dinosaurs 65 million years ago? Scientists have just begun to track distant asteroids and comets that may pose a threat to Earth in years to come. Scientific American Hocus: Cosmic Collisions traces the history of cosmic collisions and proposes various solutions to what many view as our impending doom, answering these questions and more: -How often does Earth experience a cosmic collision?-Did a massive collision kill off the dinosaurs?-How do scientists track and predict collisions?-What did we learn from the Jupiter collision of 1994?-How real is the threat of a collision in our future?-How can we defend our planet?