Time-lapse movies made from a series of pictures taken by NASA's Hubble Space Telescope are showing astronomers that young stars and their surroundings can change dramatically in just weeks or months. As with most children, a picture of these youngsters taken today won't look the same as one snapped a few months from now. The movies show jets of gas plowing into space at hundreds of thousands of miles per hour and moving shadows billions of miles in size. The young star systems featured in the movies, XZ Tauri and HH 30, reside about 450 light-years from Earth in the Taurus-Auriga molecular cloud, one of the nearest stellar nurseries to our planet. Both systems are probably less than a million years old, making them relative newborns, given that stars typically live for billions of years.