A dark matter halo is a hypothetical component of a galaxy that envelops the galactic disk and extends well beyond the edge of the visible galaxy. The halo's mass dominates the total mass. Since they consist of dark matter, halos cannot be observed directly, but their existence is inferred through their effects on the motions of stars and gas in galaxies. Dark matter halos play a key role in current models of galaxy formation and evolution.
Read more about Dark Matter Halo: Rotation Curves As Evidence of A Dark Matter Halo, Theories About The Nature of Dark Matter, Milky Way Dark Matter Halo
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