They are blasted away from a disk of gas and dust falling onto an embryonic star. Light from the star illuminates the top and bottom surfaces of the disk, making them visible, while the star itself is hidden behind the densest parts of the disk. The reddish jet emanates from the inner region of the disk, and possibly directly from the star itself. Hubble's detailed view shows, for the first time, that the jet expands for several billion miles from the star, but then stays confined to a narrow beam. HST's detailed view shows that the jet has burrowed a cavity through the dense gas cloud and now travels at high speed into interstellar space.
Shock waves form when the jet collides with interstellar gas, causing the jet to glow.
The scale in the bottom left corner of each picture represents 93 billion miles, or 1,000 times the distance between Earth and the Sun. All images were taken with the WFPC 2 in visible light.