According to the World Nuclear Association, fusion "offers the prospect of an almost inexhaustible source of energy for future generations". Scientists pursued this dream for more than four decades. Then in 2004, an American named Rusi Taleyarkhan claimed he had made the great leap forward. He had created nuclear fusion in his lab using sound waves.
Nuclear fusion is the process by which the sun and other stars create their gargantuan amounts of energy. It's also the energy that was behind the Big Bang, which scientists believe occurred approximately three minutes after the macrocosmos began. Physically, fusion is the process by which two nuclei are joined together. In the sun, fusion turns hydrogen into helium. On Earth, we use fuel such as Deuterium, Tritium (both forms of Hydrogen) and Helium to create fusion reactions. So far, we've only managed to use fusion in thermonuclear weapons. But this could soon all change.
Why we care
Successfully harnessed, nuclear fusion could be the answer to the world's energy shortage. Just 10g of Deuterium (which can be extracted from 500L of water) and 15g of Tritium (found in 30g of Lithium) could provide enough energy to last you or me a lifetime. The materials required to create fusion energy are cheap and plentiful on Earth, and there is no danger of a nuclear meltdown, as with the nuclear energy we use today. Any malfunction in a fusion reaction results in a rapid shutdown. In addition, there are no associated pollutants, and the radioactivity created decays rapidly, so there is no radioactive waste for future generations to clean up.
The origins of fusion
Early scientific thinkers theorised that the sun was just a big ball of fire, burning up it's own combustible resources, just like a super-inflated fireplace. By the mid-19th century, people started to think that maybe the sun's energy came from its own gravitational collapse. When Einstein came up with his special theory of relativity and the equation E=mc2, people began to realise that a significant amount of energy could be created from a tiny amount of mass. By 1940, through the work of several scientists, a general theory for fusion reactions was finally understood.
Early fusion research
The successful development of the first nuclear weapons proved that fusion on Earth was possible, and drove scientists to explore possible peaceful applications. Research in Britain during the 50s on the Zero Energy Toroidal Assembly (ZETA), a stabilised toroidal pinch device, gave early positive evidence that spurred further research. During the following five decades, scientists from around the world, including America, Britain, France, Russia, Germany and Japan shared information and ideas about their work on nuclear fusion. Small, but steady, steps toward harnessing fusion energy have been made, and the progress continues today.