Normal matter—the kind that makes up our home planet and everything we can see—adds up to just five percent of the known universe. The other 95 percent is dark matter and dark energy. NASA’s Nancy Grace Roman Space Telescope will settle essential questions about this dark side, especially dark energy, one of the biggest mysteries in all of science. In this encore presentation, hear how NASA astrophysicists study dark matter and dark energy and why they are making scientists reconsider our basic understanding of the universe. 

This episode was originally published in 2023. For the latest news about NASA’s Nancy Grace Roman Space Telescope, visit nasa.gov/roman.