The American Museum of Natural History is planning a major exhibit of million-year-old hominid fossils from Spanish excavation sights. "Origins: Treasures from the Hills of Atapuerca" opens January 11, 2003, and continues through April 13 of that year. There'll be some 70 fossils and artifacts on display, including tools, and this will be the first time the items go on view outside Spain. (Also note the massive Albert Einstein exhibit, reviewed separately)Of course, any visit to the museum can be the occasion for also visiting the impressive new Planetarium. The museum also offers special presentations at various times, such as its one-time July 25 performance, staged for the press the day before, showcasing a customized supercomputer-powered offering. The sounds of a theremin instrument served to drive a three-dimensional display on the dome of the Planetarium. Electronic music by theremin player Pamelia Kurstin helped project the imagery on the overhead space. At the American Museum of Natural History, Central Park West at 79th Street. Phone: 212-769-5100.