Splitting the uranium atom powers all the nuclear power plants in the world. Fusing together two small hydrogen atoms has also been done. This is called a hydrogen bomb. Fusion also powers the Sun. Harnessing this most abundant atom on Earth for peaceful purposes has long been a scientific dream. All you need is a lot of pressure, like the mass of the Sun, or freakishly high temperatures. In the next few days, at the National Ignition Facility in Livermore, California, researchers inside a high-security building the size of a football stadium are scheduled to start "credible ignition experiments": using a laser that can focus twice the power of the US electrical grid onto a one-millimetre space, creating the energy necessary for fusion. It won't happen right away - estimates range between one and two years - and the mechanics of the thing are daunting. A pea-sized plastic capsule houses a mixture of deuterium and tritium, the two heavy isotopes of hydrogen. For 20 billionths of a second, a laser zaps it with 500 trillion watts. Ten billionths of a second later: kablooey!
Mastering the technology could provide the Earth with an unlimited source of heat and energy. It won't come cheap. The facility alone, which opened in the spring of 2009, cost $3.5 billion, but the long-term prospects of fusion fuel are nothing short of glorious.