Book excerpt: What happens when two massive hunks of hurtling space debris slam into each other? Welcome to round one in the Cosmic Collisions series--an exciting children's debut from an expert astrophysicist. There's a comet speeding in from the outer solar system, and it's about to slam into an asteroid. Who will be left standing after this interplanetary smackdown? The pockmarked asteroid, a veteran fighter who's already seen some action? Or the dazzling comet, with its incredible velocity and a tail that stretches millions of miles? Kicking off a dynamic series on cosmic collisions, Asteroid vs. Comet starts by comparing the two opponents, then offers hints and context to encourage readers to use real science to form a hypothesis. Action-packed full-color illustrations with a graphic, comic-book feel will attract reluctant readers and kids who love smash-and-crash along with budding scientists. Curious readers can find back matter addressing the question of fact versus fiction, how to become a citizen scientist, and comets and asteroids in the news.