what are the components of the universe

The universe is made up mostly of dark energy and dark matter , with only a small fraction being the ordinary matter that makes stars, planets, and people.

Big Picture: What fills the universe?

Cosmological measurements (like the cosmic microwave background and distant supernovae) show that the universe’s total mass–energy budget is dominated by components we cannot see directly. Ordinary matter and light are just the visible frosting on a much deeper cosmic “cake.”

Main components (with rough proportions)

• Dark energy (~68–70%)
  • Acts like a repulsive form of energy built into space itself.

* Drives the observed accelerated expansion of the universe today.

• Dark matter (~25–27%)
  • Invisible, does not emit or absorb light, but has gravity.

* Forms the gravitational “scaffolding” on which galaxies and clusters assemble.

• Ordinary (baryonic) matter (~5%)
  • Atoms that make up stars, planets, gas, dust, and living things.

* Mostly hydrogen and helium formed shortly after the Big Bang, plus heavier elements made inside stars.

• Radiation (photons, plus a tiny contribution from neutrinos, <0.01%)
  • Includes all electromagnetic radiation, especially the cosmic microwave background, the afterglow of the Big Bang.

* Once dominated the young universe, but now is a very small part of the total energy budget.

How scientists describe it in practice

In modern cosmology, a simple way to summarize “what are the components of the universe” is:

• Dark energy: the main driver of current cosmic expansion.

• Dark matter: the main source of gravitational mass shaping large-scale structure.

• Ordinary matter: the stuff all visible structures are built from.

• Radiation: the fading relic light and high‑energy particles from the early universe.

Today’s picture could still evolve as new physics appears, but these four components form the standard, widely used framework in cosmology.