In 2014, the International Space Station had to move three times to avoid lethal chunks of space debris and there is an increasing problem of satellites mysteriously breaking down. With first-hand accounts from astronauts and experts, know the scale of the problem of space junk. Our planet is surrounded by hundreds of millions of pieces of junk moving at 17,000 miles per hour. Now the US government is investing a billion dollars to track them, and companies around the world are developing ways to clear up their mess - from robot arms to nets and harpoons. Learn the science behind the hit film Gravity and discovers the reality is far more worrying than the Hollywood fiction.

Our universe seems real. But what if it’s a videogame? Scientists in a variety of fields are taking seriously the possibility that we live in a virtual reality. Maybe the Big Bang was just the moment someone flipped the switch and turned on our universe. Maybe what looks random has already been programmed to happen. If some advanced civilization did design and program our universe, would we ever know? Scientists are looking for glitches in the laws of the universe that may uncover its hidden code.

Tyson begins the episode by explaining the nature of the speed of light and how much of what is seen of the observable universe is from light emanated from billions of years in the past. Tyson further explains how modern astronomy has used such analyzes via deep time to identify the Big Bang event and the age of the universe. Tyson proceeds to describe how the work of Isaac Newton, William Herschel, and James Clerk Maxwell contributed to understanding the nature of electromagnetic waves and gravitational force, and how this work led towards Albert Einstein's Theory of Relativity, that the speed of light is a fundamental constant of the universe and gravity can be seen as distortion of the fabric of space-time. Tyson describes the concept of dark stars as postulated by John Michell which are not visible but detectable by tracking other stars trapped within their gravity wells, an idea Herschel used to discover binary stars. Tyson then describes the nature of black holes, their enormous gravitational forces that can even capture light, and their discovery via X-ray sources such as Cygnus X-1. Tyson uses the Ship of Imagination to provide a postulate of the warping of spacetime and time dilation as one enters the event horizon of the black hole, and the possibility that these may lead to other points within our universe or others, or even time travel. Tyson ends on noting that Herschel's son, John would be inspired by his father to continue to document the known stars as well as contributions towards photography that play on the same nature of deep time used by astronomers.

Dr Adam Rutherford tells the extraordinary story of the scientific quest to discover the secrets of the cell and of life itself. Every living thing is made of cells, microscopic building blocks of almost unimaginable power and complexity. The first part explores how centuries of scientific and religious dogma were overturned by the earliest discoveries of the existence of cells, and how scientists came to realize that there was, literally, more to life than meets the eye.

This episode explores the palaeogeography of Earth over millions of years, and its impact on the development of life on the planet. Tyson starts by explaining that the lignin-rich trees evolved in the Carboniferous era about 300 million ago, then explains on the nature of plate tectonics that would shape the landmasses of the world and the asteroid impact that initiated the Cretaceous–Paleogene extinction event, leaving small mammals as the dominate species on earth. Earth's landmasses are expected to change in the future and postulates what may be the next great extinction event.

Documentary telling the little-known story of how Darwin came to write his great masterpiece, On the Origin of Species, a book which explains the wonderful variety of the natural world as emerging out of death and the struggle of life. In the twenty years he took to develop a brilliant idea into a revolutionary book, Darwin went through a personal struggle every bit as turbulent as that of the natural world he observed. Fortunately, he left us an extraordinary record of his brilliant insights, observations of nature, and touching expressions of love and affection for those around him. He also wrote frank accounts of family tragedies, physical illnesses and moments of self-doubt, as he laboured towards publication of the book that would change the way we see the world.