Inexplicable Universe: Unsolved Mysteries

Do viewers know that electrons have never actually been observed by scientists to this day? Or that quarks cannot be studied in isolation? Or being in stronger gravity or traveling rapidly slows the ticking of time relative to the rest of the universe? Delve into these and other mind-warping facts about the fundamentals of matter in a episode that covers everything from particle physics to quantum tunneling.

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 is meant by scientists who hope to find examples of life that is 'intelligent'?

Turn now to some inexplicable aspects of physics and the physical world. Among the many eye-opening topics viewers will learn about in this episode are the discovery of more and more elements on the periodic table; muon neutrinos, tao particles, and the three regimes of matter; the secrets of string theory; and even the hypothetical experience of traveling through a black hole.

Shoot off into the stars for an investigation of some perplexing aspects of space that science has uncovered in the last half-century. Learn about the mysterious trajectory of the Pioneer spacecraft (known as the 'Pioneer anomaly'). Explore two of the longest-standing problems in modern astrophysics: dark matter and dark energy. And even try to map out the shape of space-time itself.