All the Contents of the Universe in One Graphic
Scientists agree that the universe consists of three distinct parts: everyday visible (or measurable) matter, and two theoretical components called dark matter and dark energy.
These last two are theoretical because they have yet to be directly measured—but even without a full understanding of these mysterious pieces to the puzzle, scientists can infer that the universe’s composition can be broken down into the following components:
Dark Energy
Dark energy is the theoretical substance that counteracts gravity and causes the rapid expansion of the universe. It is the largest part of the universe’s composition, permeating every corner of the cosmos and dictating how it behaves and how it will eventually end.
Dark Matter
Dark matter, on the other hand, has a restrictive force that works closely alongside gravity. It is a sort of “cosmic cement” responsible for holding the universe together. Despite avoiding direct measurement and remaining a mystery, scientists believe it makes up the second largest component of the universe.
Free Hydrogen and Helium
Free hydrogen and helium are elements that are free-floating in space. Despite being the lightest and most abundant elements in the universe, they make up roughly 4% of its total composition.
Stars, Neutrinos, and Heavy Elements
All other hydrogen and helium particles that are not free-floating in space exist in stars.
Stars are one of the most populous things we can see when we look up at the night sky, but they make up less than one percent—roughly 0.5%—of the cosmos.
Neutrinos are subatomic particles that are similar to electrons, but they are nearly weightless and carry no electrical charge. Although they erupt out of every nuclear reaction, they account for roughly 0.3% of the universe.
Heavy elements are all other elements aside from hydrogen and helium.
Elements form in a process called nucleosynthesis, which takes places within stars throughout their lifetimes and during their explosive deaths. Almost everything we see in our material universe is made up of these heavy elements, yet they make up the smallest portion of the universe: a measly 0.03%.