A bow shock can be created in space when two streams of gas collide. LL Ori emits a vigorous stellar wind, a stream of charged particles moving rapidly outward from the star. This stellar wind collides with slow-moving gas evaporating away from the center of the Orion Nebula, which is located to the lower left in this image. The surface where the two winds collide is the crescent-shaped bow shock seen in the image. A second, fainter bow shock can also be seen around a star near the upper left-hand corner of the image.

Credits: NASA/ESA and The Hubble Heritage Team STScI/AURA

Due to the interaction of permanently incoming solar wind (coming from the left of the figure) with Earth's magnetosphere, a permanent collisionless shock called the bow shock (depicted by the yellow arc) is formed. The bow shock forms in front of the nose of the magnetopause – the external boundary layer of the magnetosphere.

Credits: ESA

Plasma shock waves are also emitted by supernova events. They are some of the most spectacular, visually striking and energetic events in the Universe.

Credits: NASA/ CXC/ M.Weiss