Time-lapse movies made from a series of pictures taken by NASA/ESA 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 (or kilometres) per hour and moving shadows billions of miles in size.