Exploring Universe: NASA - Black Hole-Powered Jets Plow Into Galaxy. Image credit: NASA
Melotte 15 by Andrés del Pozo Prieto Situated some 7500 light years away from Earth and is located in the Perseus Arm of the Galaxy in the constellation Cassiopeia. This is an emission nebula showing glowing gas and darker dust lanes. The nebula is formed by plasma of ionized hydrogen and free electrons.
The Rosette Nebula is in the Monoceros region of the Milky Way Galaxy. The cluster and nebula lie at a distance of some 5,200 light-years from Earth and measure roughly 130 light years in diameter. The radiation from the young stars excite the atoms in the nebula, causing them to emit radiation themselves producing the emission nebula we see.