A constellation is a group of stars that are connected together to form a figure or picture. Explore some of the 88 official constellations and learn about some of the highlights of each.

Professor Jim Al-Khalili investigates the most accurate and yet perplexing scientific theory ever - quantum physics. At the beginning of the 20th century scientists were led into the hidden workings of matter, into the sub-atomic building blocks of the world around us. They discovered phenomena unlike any encountered before - a realm where things can be in many places at once, where chance and probability call the shots and where reality appears to only truly exist when we observe it. Albert Einstein hated the idea that nature, at its most fundamental level, is governed by chance. Jim reveals how, in the 1930s, Einstein thought he'd found a fatal flaw in quantum physics because it implies that sub-atomic particles can communicate faster than light in defiance of the theory of relativity. In the 1960s the scientist John Bell showed there was a way to test if Einstein was right and quantum mechanics was actually mistaken. Jim repeats this critical experiment - with shocking results.

This scientific detective tale tells the story of a remarkable group of pioneers who wanted to reach the ultimate extreme: absolute zero, a place so cold that the physical world as we know it doesn't exist, electricity flows without resistance, fluids defy gravity and the speed of light can be reduced to 38 miles per hour. Absolute zero became the Holy Grail of temperature physicists and is considered the gateway to many new technologies, such as nano-construction, neurological networks and quantum computing. The possibilities, it seems, are limitless. The first episode Chronicles the major discoveries leading towards the mastery of cold, beginning with King James I's court magician, Cornelius Drebbel, who managed to air condition the largest interior space in the British Isles in 1620. Other stories will include the first "natural philosopher," Robert Boyle, a founder of the Royal Society in Great Britain; the Grand Duke Ferdinand II de Medici's involvement in the creation of the first thermometer; the establishment of the laws of thermodynamics by three young scientists, Sadi Carnot, James Joule and William Thomson; and Michael Faraday's critical achievement in liquefying several other gases which set the stage for the commercial application of cold to refrigeration and air conditioning.

An apocryphal view on the pyramids, starting in awe at the amazing achievement of the Pharaonic architecture and sculpture, most specially at Gizeh, given Cheops's pyramid's size, weight, incredibly precise carving, four pairs of slightly shifted half sides, stunningly precisely measured shapes and symmetry. Then it questions and challenges conventional Egyptology beliefs, which it calls unproven or even impossible to verify, such as the absence of machines, a wharf duration of only 20 years or accidental equinox-orientation. Next it elaborates the theory that other major pyramid technology sites in Precolombian America, Easter Island and China can't coincidentally lie on two lines intersecting at Gizeh, even if not contemporaneous and without known contacts in their ages, and have several improbable things in common, like some of their cultures. Elaborate mathematical theories and measurements indicate the Egyptians must have known some astronomy, pi and the golden number

How does light escape from the sun? We take a journey from the center of the sun, following the path of light. We witness its fiery birth from in the core, its 430,000 mile battle against gravity and magnetism, and its escape from the solar surface.

The contests between predators and prey are the most dramatic events in nature. Taking an intimate and detailed look at the remarkable strategies employed by hunters to catch their prey and the hunted to escape. Sir David Attenborough narrates. "The Hardest Challenge" reveals the extraordinary range of techniques predators use to catch their prey - from a leopard using all its powers of stealth to stalk impala in broad daylight to wild dogs, whose tactic is to wear down their prey over long distances; from Nile crocodiles, the planet's most patient predators, to killer whales who use teamwork and intelligence to take on humpback whales. But even with these finely tuned strategies, the outcome is far from certain. Surprisingly, most predators fail most of the time.