Here, take a closer look at concepts that were once unexplainable but, thanks to modern physics, are now better understood. You'll focus on two such former mysteries: the existence of an invisible "aether" through which light and sound were believed to travel and the orbit of Mercury, which seemed (to earlier scientists) to violate Newton's fundamental laws of motion.

Join Professor Tyson on a fascinating investigation of the possible origins of life in the universe. Why was Jupiter believed to be a good environment for life in the 17th century? Why is there only one single "tree of life" on Earth instead of multiple ones? Could life have come from another planet? And what exactly do we mean when we hope to find examples of life that is "intelligent"?