Taught by Sean Carroll California Institute of Technology Ph.D., Harvard University There's more to the universe than meets the eyea lot more. In recent years scientists have discovered that 95 percent of the contents of the cosmos are invisible to all of our current methods of direct detection. Yet they are definitely there: Something is holding galaxies and galaxy clusters together, and something else is causing space itself to fly apart. Scientists call these invisible components dark matter and dark energy"dark" because these phenomena don't emit light, not because we aren't learning more and more about them. Indeed, dark matter and dark energy are the most eagerly studied subjects in astronomy and particle physics today