We float along the river of time. But does that river have a source? Where did time come from? Some believe time and space are one thing, and the Big Bang started the cosmic clock. Others believe the universe existed for almost half a million "years" before light could move and time began. Still others say time is older than our universe. But what if time itself is an illusion? Incredible new experiments may hold the answer. One groundbreaking experiment gives us the power to punch holes in time…and another may create a machine that operates outside time’s boundaries!

Beginning with the separation of the fuzzy thinking and pious fraud of astrology from the careful observations of astronomy, Sagan follows the development of astronomical observation. Beginning with constellations and ceremonial calendars (such as those of the Anasazi), the story moves to the debate between Earth and Sun-centered models: Ptolemy and the geocentric worldview, Copernicus' theory, the data-gathering of Tycho Brahe, and the achievements of Johannes Kepler (Kepler's laws of planetary motion and the first science-fiction novel).

Brian explores the physics of the size of life through some close encounters with Australia's wildlife. From swimming with great white sharks to tracking red kangaroos, he discovers that the size you are profoundly affects the life you lead and, ultimately, how long you have to enjoy it.

What is the universe made of? If you answered stars, planets, gas and dust, you'd be dead wrong. Thirty years ago, scientists first realized that some unknown dark substance was affecting the way galaxies moved. Today, they think there must be five times our understanding of the universe and the nature of reality itself has drastically changed over the last 100 years - and it's on the verge of another seismic shift. In a 17-mile-long tunnel buried 570 feet beneath the Franco-Swiss border, the world's largest and most powerful atom smasher, the Large Hadron Collider, is powering up. Its goal is nothing less than recreating the first instants of creation, when the universe was unimaginably hot and long-extinct forms of matter sizzled and cooled into stars, planets, and ultimately, us. These incredibly small and exotic particles hold the keys to the greatest mysteries of the universe. What we find could validate our long-held theories about how the world works and what we are made of -- or, all of our notions about the essence of what is real will fall apart.

Embark on an astounding journey across 100,000 light-years to witness key moments in the history of the Milky Way. Using cutting-edge science, National Geographic constructs a 3-D state-of-the-art CGI model of our galaxy. We'll peer into the heart of the Milky Way on the hunt for super-massive black holes, watch how stars are born and die, fly out and above the plane of our galaxy to understand its true shape and scour its dusty spiral arms for the possibility of life

After eight grueling years of hunting in the hot, wind-scoured desert of central Africa, an international team of researchers has uncovered one of the most sensational fossil finds in living memory: the well-preserved 7 million years old skull of a chimp-size animal, probably a male, that doesn't fit any known species. According to paleontologist Michel Brunet of the University of Poitiers in France, whose team reported the find in Nature last week, there is no way it could have been an ape of any kind. It was almost certainly a hominid — a member of a subdivision of the primate family whose only living representative is modern man.