The Milky Way galaxy has a diameter of 100,000 light-years and contains approximately 400 billion stars. It consists of three main regions: the disk, which is populated by young stars and gas; the bulge, containing a mix of young and old stars; and the halo, made up of older stars with no gas. Dark matter, which vastly outweighs visible matter, plays a crucial role in galactic structure and dynamics, while the expansion of the universe is influenced by the mysterious dark energy.
Related topics: