M82ΓÇÖs extensive dust clouds are probably also responsible for the red light emanating from the center of the galaxy. When light travels through regions that contain dust, some of it strikes the dust grains and is either absorbed or scattered. Light with shorter wavelengths (blue) is more likely to strike these small grains than light with longer wavelengths (red). The same phenomenon causes the Sun to appear red in the late afternoon: as it sinks lower in the sky its light has to travel through more air before it reaches the eye. Most of the blue light has scattered or absorbed leaving the red that we see.
At one time, M82 was thought to be an exploding galaxy, torn
