Milky Way Galaxy Top View
Related: Milky Way Milky Way Galaxy Milky Way Center Milky Way 1995 Milky Way Bar Milky Way Galaxy Definition Milky Way Candy Bar Milky Way BrowniesWiki info
Much of the mass of the Milky Way seems to be dark matter, an unknown and invisible form of matter that interacts gravitationally with ordinary matter. A dark matter halo is conjectured to spread out relatively uniformly to a distance beyond one hundred kiloparsecs (kpc) from the Galactic Center. Mathematical models of the Milky Way suggest that the mass of dark matter is 1–1. 5×1012 M☉.  Recent studies indicate a range in mass, as large as 4. 5×1012 M☉ and as small as 8×1011 M☉.  The total mass of all the stars in the Milky Way is estimated to be between 4. 6×1010 M☉ and 6. 43×1010 M☉. In addition to the stars, there is also interstellar gas, comprising 90% hydrogen and 10% helium by mass, with two thirds of the hydrogen found in the atomic form and the remaining one-third as molecular hydrogen.  The mass of the Milky Way's interstellar gas is equal to between 10% and 15% of the total mass of its stars. Interstellar dust accounts for an additional 1% of the total mass of the gas.