All of the ordinary matter in the universe, from stars to Cher herself, accounts for less than 5% of the known universe. About 25% of the universe is dark matter, while the remaining 70% is dark energy.
But what are these dark, invisible substances? Well…we don't know exactly, but we do have some ideas!
With dark matter for example, we know:
Dark energy, on the other hand, is even more strange.
Kurzgesagt digs into the mystery in the video below: