Looking up at the night sky is an amazing way to get in touch with the universe, but even though we can see stars, nebula and other galaxies, the majority of the universe is made up of material we can’t see. Dubbed ‘dark matter,’ this unobservable material makes up nearly 80 percent of the universe — it is, quite literally, the glue that holds the universe together. Scientists have spotted galaxies made almost entirely of dark matter, such as the galaxy dubbed Dragonfly 44.
What is dark matter, and why is it so surprising scientists may have found a galaxy that completely lacks this elusive material?
What Is Dark Matter?
Think back to your middle school science classes where you learned about neutrons, electrons and protons. These three types of particles are dubbed baryonic matter and make up the visible materials that we are familiar with.
Dark matter is most likely made up of non-baryonic matter — particles that don’t interact with the neutrons, electrons and protons in any normal way. That lack of interaction makes these particles nearly impossible to detect — we only know it’s there because we can observe the movement of stars. There is some form ...