what's the diameter of the milky way
Milky Way The Milky Way is a barred spiral galaxy with a diameter between 100,000[30] and 180,000 light-years.[31] The Milky Way is estimated to contain 100–400 billion stars.[32][33] There are probably at least 100 billion planets in the Milky Way.[34][35] The Solar System is located within the disk, about 26,000 light-years from the Galactic Center, on the inner edge of one of the spiral-shaped concentrations of gas and dust called the Orion Arm. The stars in the inner ≈10,000 light-years form a bulge and one or more bars that radiate from the bulge. The very center is marked by an intense radio source, named Sagittarius A*, which is likely to be a supermassive black hole.
Milky Way The Milky Way contains between 200 and 400 billion stars[61][62] and at least 100 billion planets.[63] The exact figure depends on the number of very-low-mass stars, which are hard to detect, especially at distances of more than 300 ly (90 pc) from the Sun. As a comparison, the neighboring Andromeda Galaxy contains an estimated one trillion (1012) stars.[64] Filling the space between the stars is a disk of gas and dust called the interstellar medium. This disk has at least a comparable extent in radius to the stars,[65] whereas the thickness of the gas layer ranges from hundreds of light years for the colder gas to thousands of light years for warmer gas.[66][67]