The “Black Widow” pulsar moves at a speed of KM/hr. A bow shock wave is the greenish crescent shape. The pressure behind the bow shock creates a second shock wave that sweeps the cloud of high-energy particles back from the pulsar to form the cocoon.
This image from the Hubble Space Telescope clearly shows the equatorial rings of Uranus, a southern cloud deck and a bright cloud in the northern hemisphere. Uranus is unique in that its axis is tilted to align with the solar system elliptic plane.
The Horse Head Nebula is a cloud of ionized- hydrogen in the constellation Orion. The clouds are lit from within by young hot stars. The interstellar dust absobs the light from part of ionized cloud creating this beautiful contrast