The universe, as far as current physics can tell, is mostly made of three big ingredients: dark energy , dark matter , and a small fraction of ordinary matter (the stuff you, stars, and planets are made of).

Big picture: cosmic recipe

In modern cosmology, a rough breakdown is:

  • About 68ā€“70% dark energy.
  • About 25ā€“27% dark matter.
  • About 5% ordinary (baryonic) matter: atoms, stars, gas, dust, planets, people.

These numbers come from observing how the universe expands and how galaxies and galaxy clusters behave on large scales.

Ordinary matter: the familiar 5%

Ordinary matter is made of atoms: protons, neutrons, and electrons bound together into elements and molecules.

On cosmic scales:

  • Hydrogen is the most common element, followed by helium; together they make up nearly all ordinary matter in the universe.
  • Heavier elements (carbon, oxygen, iron, etc.) are a tiny fraction, forged in stars and supernovae and then recycled into new stars and planets.

Everything we can see directly with telescopesā€”stars, nebulae, galaxies, our bodiesā€”is built from this ordinary matter.

Dark matter: invisible scaffolding

Dark matter does not emit, absorb, or reflect light, so it is invisible to telescopes.

Scientists infer its existence because:

  • Galaxies rotate so fast that, without extra unseen mass, they would fly apart; dark matterā€™s gravity holds them together.
  • Gravitational lensing (bending of light) around galaxy clusters is much stronger than visible matter alone can explain.

Dark matter acts like a cosmic scaffold , providing the gravitational framework in which galaxies and clusters form and evolve.

Its exact particle nature is still unknown, and uncovering it is one of the biggest open problems in physics.

Dark energy: the mysterious driver

Dark energy is a form of energy that appears to be built into space itself and is linked to the accelerated expansion of the universe.

Key points:

  • Distant supernova observations show that the universeā€™s expansion is speeding up, which implies some repulsive effect on large scales.
  • In the standard model of cosmology, about 70% of the universeā€™s total energy budget is this dark energy component.

There are several ideasā€”like a cosmological constant or dynamic fieldsā€”but no consensus yet on what dark energy ā€œreallyā€ is.

Radiation and other minor components

A tiny fraction of the universe consists of light and other forms of radiation:

  • Electromagnetic radiation (starlight, cosmic microwave background, radio waves, etc.) is estimated to be around 0.005ā€“0.01% of the total massā€“energy.
  • There is also a small contribution from neutrinos and traces of antimatter, but these are minor compared to dark energy, dark matter, and ordinary matter.

Even though radiation is a small percentage today, it played a crucial role in the early universe when everything was much hotter and denser.

Information gathered from public sources and scientific agencies available on the internet and portrayed here.