From the discovery that the Milky Way is just one galaxy among billions to the stunning revelation that these galaxies are speeding away from each other faster every second, this episode investigates the universeā€™s distant past ā€” and its future. Now, modern telescopes have added a mysterious new twist to the plot: The vast majority of the stuff of the universe is invisible, tied up in dark matter and dark energy. But what are these mysterious dark forces? A new generation of telescopes is embarking on a mission impossible to see the unseeable and answer one of the greatest unsolved mysteries of the cosmos.