Bow shock in Orion Nebula. Optical Hubble Space Telescope (HST) image of the bow shock around the young (T-Tauri) star LL Ori, in the Orion Nebula. This star's bow shock (bright crescent at right of the star, centre) is over a tenth of a light year across. It is created as two gas streams collide. Here, LL Ori's fast stellar wind (the stream of charged particles emitted in all directions by a star), collides with the surrounding gas and dust of the Orion Nebula. The collision causes the gases to glow. A fainter bow shock is at upper right. The Orion Nebula lies about 1500 light years away. Photographed in 1995.