Timeline of the universe

The universe began about 13.8 billion years ago with the Big Bang, an incredibly hot and dense explosion. Immediately afterward, space, time, and matter started to expand and cool. Within seconds, elementary particles formed, and later atoms like hydrogen and helium emerged. Over millions of years, these atoms gathered into clouds, stars, and galaxies. Our solar system developed about 4.6 billion years ago. Throughout billions of years, stars and galaxies evolved, with some stars ending their lives as supernovae, creating heavier elements. Today, the universe continues expanding, with galaxies moving apart.