We are in the grip of an allergy epidemic. 50 years ago one in 30 were affected, but in Britain today it is closer to one in three. Why this should be is one of modern medicine's greatest puzzles. In search of answers, Horizon travels round the globe, from the remotest inhabited island to the polluted centres of California and the UK. We meet sufferers and the scientists who have dedicated their lives trying to answer the mystery of why we are becoming allergic to our world.

Scientists have no idea what it is, but Dark Matter and Dark Energy make up 96% of the Universe. Dark Matter is everywhere. It passes through everything we know on earth at billions of particles every second, yet no one has ever gotten a direct detection of this mysterious dark substance. An even more bewildering force is Dark Energy, which is rapidly pushing apart our Universe. Discovered only ten years ago, scientists are struggling to comprehend its unusual characteristics and answer the ultimate question; what is the fate of our Universe? Using cutting-edge computer graphics watch as the universe is brought down to earth.

Does life exist on other planets? Astrobiology is a visionary new science that searches for life in space by combining the disciplines of astronomy, biology and geology. How did life evolve on Earth? What will life look like on other planets? These and other pertinent questions will be answered by a diverse group of scientists. Viewers will visit the Pilbara region of West Australia where the oldest evidence of life on Earth has been discovered. Travel to the moons of Jupiter and Saturn to test a theory that life could exist in the clouds of Venus. Finally, watch as experiments are done to see if life exists on exoplanets, earth-like planets beyond our solar system.

When man finally broke free of the Earth's gravitational pull the dream of travelling to other planets became a reality. Today scientists are proposing a bizarre array of technologies in the hope of travelling faster through space: from space craft sporting sails that catch laser beams, to propulsion engines powered by a bizarre entity known as anti-matter. Finally explore the science behind the seemingly fanciful notion of warp-drive and a theoretical particle that can travel faster than light.

A stellar explosion, the supernova is the sensational death of a star. It can shine as bright as 100 billion Suns and radiate as much energy as the Sun would emit over 10 billion years. Jets of high-energy light and matter are propelled into space and can cause massive Gamma Ray Bursts and emit intense X-ray radiation for thousands of years. Astronomers believe that this process creates the very building blocks of planets, people and plants. Meet the world's leading Supernova hunters, and take a look at recorded supernovas throughout history.

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.