Stellar Lifespan

A star's lifespan depends mainly on its mass. Larger stars burn their fuel quickly, shining brightly but for a shorter time—sometimes a few million years. Smaller stars, like red dwarfs, burn fuel slowly and can shine for trillions of years, much longer than the universe has existed. The process involves nuclear fusion, where hydrogen atoms fuse to form helium, releasing energy that makes stars luminous. Over time, stars exhaust their fuel, leading to eventual changes such as expanding into giants or collapsing into dense objects like white dwarfs, neutron stars, or black holes, marking the end of their lifecycle.