The Milky Way is a spiral galaxy that contains billions of stars, estimated to be around 100 to 400 billion. These stars vary in size, brightness, and color, ranging from small, cool red dwarfs to massive, hot blue giants. Most stars in the Milky Way are grouped in clusters or are part of the galaxy's spiral arms. Stars in the Milky Way are formed from clouds of gas and dust, known as nebulae. Over time, gravity pulls these materials together, leading to nuclear fusion in the core, which produces light and heat. The life cycle of a star can last millions to billions of years, ending in various ways, such as becoming a supernova or a white dwarf.