Animation: Visualization of 140 years of global surface temperatures

All 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 measured directly — but even without a full understanding of these mysterious pieces of the puzzle, scientists can conclude that the composition of the universe can be broken down as follows:

Let’s take a closer look at each component.

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 composition of the universe, permeating every corner of the cosmos and determining how it will behave and how it will eventually end.

Dark matter

Dark matter, on the other hand, has a restrictive force that works closely with gravity. It is a kind of “cosmic glue” responsible for holding the universe together. Although direct measurement is avoided and remains a mystery, scientists believe it represents the second largest component of the universe.

Free hydrogen and helium

Free hydrogen and helium are elements that float freely in space. Despite being the lightest and most abundant elements in the universe, they make up about 4% of its total composition.

Stars, neutrinos and heavy elements

All other hydrogen and helium particles that are not floating freely 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 — about 0.5% — of the cosmos.

Neutrinos are subatomic particles that resemble electrons but are nearly weightless and carry no electrical charge. Although they erupt with every nuclear reaction, they make up about 0.3% of the universe.

Heavy elements are all other elements except hydrogen and helium.

Elements form in a process called nucleosynthesis, which takes place in stars throughout their lifetime and during their explosive death. Almost everything we see in our material universe is made up of these heavy elements, but they make up the smallest part of the universe: a meager 0.03%.

How do we measure the universe?

In 2009, the European Space Agency (ESA) launched a space observatory called Planck to study the properties of the universe as a whole.

Its main task was to measure the afterglow of the explosive Big Bang that gave birth to the universe 13.8 billion years ago. This afterglow is a special type of radiation called cosmic microwave background radiation (CMBR).

Temperature can tell scientists a lot about what exists in space. Studying the “microwave sky,” researchers are looking for variations (called anisotropy) in the temperature of CMBR. Instruments like Planck are helping to reveal the magnitude of the anomalies in the CMBR temperature and informing us about the various components that make up the Universe.

You can see below how CMBR clarity changes over time with multiple space missions and more sophisticated instruments.

What else is there?

Scientists are still working to understand the properties that make up dark energy and dark matter.

NASA is currently planning to launch the Roman Space Telescope Nancy Grace in 2027, an infrared telescope that will hopefully help us measure the effects of dark energy and dark matter for the first time.

And what is beyond the universe? Scientists aren’t sure.

There are hypotheses that there could be a larger “superuniverse” that contains us, or that we are part of an “island” universe separate from other island multiverses. Unfortunately, we can’t measure anything that far. Unlocking the mysteries of the deep cosmos remains a local endeavor, at least for now.