These images taken by NASA's Hubble Space Telescope show how a bright, clumpy jet ejected from a young star has changed over time.
The jet, called Herbig-Haro 34 (or HH 34), is a signpost of star birth. Several bright regions in the lumpy gas signify where material is slamming into each other, heating up, and glowing. The images show that a couple of bright areas on the right faded over time, as heated material cooled (shown in red). Two regions at left, however, brightened over the 14-year span of observations, pinpointing fresh collision sites. The blue fan-shaped feature at left outlines the edge of the outflow cavity, illuminated by the fledgling star. A small knot of material within the blue feature is either a new jet or magnetic energy being emitted by the star.
Ejected episodically by a young star like salvos from a cannon, the blobby material in HH 34 zips along at more than 440,000 miles (700,000 kilometers) an hour. When launched, the speedy jet may initially be confined to a narrow beam by the star's powerful magnetic field.
These images are part of a series of time-lapse movies astronomers have made showing the motion of several Herbig-Haro jets over time. The movies were stitched together from images taken over a 14-year period by Hubble's Wide Field Planetary Camera 2. Hubble followed the HH 34 jets over three epochs: 1994, 1998, and 2007.
HH 34 is roughly 1,350 light-years from Earth, near the Orion Nebula.