Imagine a region in space where the force of gravity is so strong that nothing—not even light—can escape. A region with physical conditions so extreme that they have not yet been reproduced in any terrestrial laboratory. A region so dense that an object as tiny as a walnut would have the same mass as our entire planet. This phenomenon—first theorized in the equations of Einstein and popularized in the stories of science-fiction authors—is a black hole: one of the most exotic, mind-boggling, and profound subjects in astrophysics. Not only are they at the heart of some of the most intriguing phenomena in the cosmos, they’re the gateway to fundamental and cutting-edge concepts like general relativity and wormholes. Nearly everyone has heard of black holes, but few people outside of complex scientific fields understand their true nature and their implications for our universe. Black Holes Explained finally makes this awe-inspiring cosmological subject accessible, with 12 lavishly illustrated lectures delivered by distinguished astronomer and award-winning Professor Alex Filippenko. As he presents the actual science behind these amazing objects, you’ll make sense of Einstein rings, photon spheres, event horizons, and other concepts central to the study of black holes. Like its subject matter, this course is intriguing, eye-opening, and essential to your knowledge of how the universe works.