Titanic collisions mark the history of our Solar System. You can see evidence in such places as Arizona's 50,000-year-old meteor crater. Is Earth due for another major blast? Meet the professional and amateur astronomers who may be the first to know: at a near-earth asteroid detection facility in New Mexico called LINEAR, and the Smithsonian's Minor Planet Center, where near-earth objects are tracked for possible hits and misses. SCIENCE BULLETINS are a production of the American Museum of Natural History… http://sciencebulletins.amnh.org/