The glowing, clumpy streams of material shown in these NASA Hubble Space Telescope images are the signposts of star birth.
Ejected episodically by young stars like salvos from a cannon, the blobby material zips along at more than 440,000 miles (770,000 kilometers) an hour. Called Herbig-Haro or HH objects, these speedy outflows have a bumpy ride through space.
When fast-moving blobs "rear-end" slower gas, bow shocks (the blue features) arise as the material heats up. Bow shocks are glowing waves of matter similar to waves produced by the bow of a ship plowing through water. In HH 2, at lower right, several bow shocks (the compact blue and white features) can be seen where fast-moving clumps bunch up like cars in a traffic jam. In HH 34, at lower left, a grouping of merged bow shocks reveals regions that brighten and fade over time as the heated material cools, shown in red, where the shocks intersect.
In HH 47, at top, a long jet of material has burst out of a dark cloud of gas and dust that hides the newly forming star. The blue, fan-shaped region at left is the edge of a cavity illuminated by the fledgling star. A massive clump of jet material collides with upstream gas, creating the white bow-shaped shock wave at right.
These images are part of a series of time-lapse movies astronomers have made showing the outflows' motion 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 jets over three epochs. Observations of HH 2 were made from 1994, 1997, and 2007; HH 34 from 1994, 1998, and 2007; and HH 47 from 1994, 1999, and 2008.
The outflows are roughly 1,350 light-years from Earth. HH 34 and HH 2 reside near the Orion Nebula, in the northern sky. HH 47 is located in the southern constellation Vela.