Dark Energy, or Worse: Was Einstein Wrong?

In this National Science Foundation program, Sean Carroll, a senior research associate at the California Institute of Technology, sheds light into the "dark side" of the universe that may actually be the key to unlocking the mystery that is the universe. The type of matter we're familiar with and encounter everyday - atoms and molecules - only makes up about 5 percent of the universe. The remaining 95 percent is believed to be dark matter and dark energy. Explore the history of dark energy and dark matter by following Einstein's path to uncovering the theory that sparked a change in the world of astrophysics and the controversies behind that theory.