The universe

The universe is the totality of all space, time, matter, and energy that exists—everything from subatomic particles to galactic superclusters. Born roughly 13.8 billion years ago in the Big Bang, it has been expanding ever since, cooling and organizing into increasingly complex structures.

Our universe contains an estimated 2 trillion galaxies, each housing billions of stars. At its largest scales, it appears relatively uniform; zoom closer and you find gravity sculpting matter into stars, planets, and black holes. Its composition remains mysterious: ordinary atoms comprise only 5%, while dark matter and dark energy dominate the rest.

Structure emerges at every scale—from neurons to nebulae, governed by physical laws that scientists continue to probe. Models and observations using advanced instruments help us decode these laws, though fundamental questions persist: Did it have a beginning? Will it end? Are we alone?

The universe inspires philosophical reflection, scientific inquiry, and profound wonder about our place in it all.

Related

Big Bang, Cosmic phenomena, Exotic matter, The universe's structure, Scale (general), Simulation