Dust lane Wikipedia
A dust lane is a relatively dense obscuring band of interstellar dust, observed as a dark swath against the background of a brighter object, especially a galaxy. These dust lanes can usually be seen in spiral galaxies, such as the Milky Way galaxy, when viewed from the edge. Due to the dense and relatively thick nature of this dust, light from the galaxy is reduced by several magnitudes (See Extinction). In the Milky Way, this reduction of light makes it impossible to see the light from the central bulge of the galaxy from Earth. This dust, as well as the gasses also found within these lanes, mix together and combine to form stars and planets.