In “The Ever-Expanding Universe,” Hour 2 of the two-part special “Hunting the Edge of Space,” NOVA investigates a battery of high-tech telescopes that is joining the Hubble Space Telescope on its quest to unlock the secrets of our universe, a cosmos almost incomprehensible in its size, age, and violence. Far beyond our solar system, we are now discovering exoplanets orbiting other suns, and beyond our galaxy, another hundred billion galaxies, such as Andromeda, Sombrero, and Whirlpool, each harboring hundreds of billions of stars. We've detected supermassive black holes, spinning violently at the very centers of galaxies, including our own. We've witnessed supernovas: exploding stars, millions of light-years away, spewing out superheated gas at 600,000 miles per hour. And deep inside clouds of gas and dust, billowing trillions of miles high, we can glimpse new stars being born. Now, the latest telescopes are revealing the invisible mysteries of space that we are only just beginning to understand: dark matter, the hidden scaffolding our entire cosmos is built on; and dark energy, a powerful and invisible force that is pushing our universe apart.