Galaxy

Our galaxy (the Milky Way) has a form of a flat disk with a diameter of about 120,000 light-years. In the middle the disc has a thickness of a few thousand light-years but it's slightly narrower at the edges, where it is roughly 1,000 light-years thick. The Milky Way contains about several hundred billion stars, a number of open and globular clusters, interstellar gas and dust and even a dark matter. Our Solar System is located in it too.



In the center of our galaxy there is a so-called galactic bulge with diameter of about 12,000 light-years, where the core of the galaxy, its densest part ‒ a giant black hole is lurking. Part of the bulge, called galactic bar, protrude into the surroundings in a form of spiral arms that give the galaxy its characteristic appearance (it resembles a pinwheel). Our Solar System with the Sun and planets is located in one of these arms ‒ in a distance of about 27,000 light-years from the galactic center. The center and the spiral disk is surrounded by a galactic halo with a diameter of about 200,000 light-years, where many very old stars and also some more globular clusters are located.