What the universe is made of
Ordinary matter makes up about 5% of the universe’s total mass and energy. The visualisation follows that share into smaller categories, showing where stars, planets and other familiar objects fit.
The overall picture
In the standard cosmological model, the universe’s present-day contents fall into three main categories:
- Dark energy: about 69%. The name given to the component associated with the accelerating expansion of the universe. Its physical nature remains uncertain.
- Dark matter: about 26%. Matter inferred from its gravitational effects, including the motions of galaxies and the bending of light around them. We have not yet identified what it consists of.
- Ordinary matter: about 5%. The material that makes up stars, gas, planets and us.
These percentages describe contributions to the total mass and energy, rather than the amount of space each component occupies.
Where ordinary matter is found
Most ordinary matter is hydrogen and helium, much of it spread through the space between and around galaxies. This gas is extremely diffuse, but it occupies such enormous regions that its total mass exceeds the amount gathered into stars.
“Ordinary” describes the type of material, not whether we can easily see it. It includes intact atoms as well as plasma, in which electrons have separated from atomic nuclei.
Stars contain a smaller share, and planets a much smaller share again. To compare those categories clearly, the visualisation changes scale several times.
Reading the visualisation
Each of the five bars expands a selected part of the bar above it. That selected portion becomes the full width of the next panel.
Every percentage belongs to its own bar. For example, if a category represents 10% of ordinary matter, it represents about 0.5% of the universe’s total mass and energy: 10% of the roughly 5% ordinary-matter share.
Start with the ordinary-matter slice in the first bar and follow the highlighted sections down. Check the label at each step to see which category is being enlarged.
The later panels distinguish stars from objects such as white dwarfs, brown dwarfs and planets. White dwarfs are the dense remnants of stars; brown dwarfs are objects too small to sustain the hydrogen fusion that powers stars like the Sun.
The repeated enlargement makes these smaller populations visible. A category that fills much of a lower panel may still represent a very small share of the original total.
How precise are the smaller categories?
The chart combines estimates with different levels of certainty. The broad cosmic proportions come from cosmological measurements interpreted through a model. The smaller categories depend on surveys and estimates of populations that are harder to observe.
Here, the amounts assigned to moons, asteroids and comets are scaled from Solar System ratios. They indicate an approximate scale, rather than a measured inventory across the universe.
Planets also contain very different materials. Much of their mass can be gas or fluid, so the planetary share should not be read as the amount of solid material in the universe.