In March 2002, the scientific world was rocked by some astonishing news: a distinguished US government scientist claimed he had made nuclear fusion out of sound waves in his laboratory. Rusi Taleyarkhan's breakthrough was such important news because nuclear fusion is one of the most difficult scientific processes, and also one of the most coveted. It could solve all of our energy problems for ever. In principle, sufficient fuel exists on earth to provide clean, pollution-free energy for billions of people for millions of years.
To make it happen, individual atoms must be slammed into each other with enough energy to make them fuse together, something that requires temperatures found only in the core of stars like our Sun – over 10 million Kelvin. The idea that these temperatures had been reached in a small scale laboratory using only soundwaves took many scientists by surprise. To them, fusion projects were huge multibillion-pound, intergovernmental schemes with the far off goal of producing energy in several decades time.
Taleyarkhan's fusion breakthrough was based on a little-understood process called sonoluminescence. It's a process that magically transforms sound waves into flashes of light, focusing the sound energy into a tiny flickering hot spot inside a bubble. It's been called the star in a jar. The star in a jar effortlessly reaches temperatures of tens of thousands of degrees, hotter than the surface of the sun. Many scientists had wondered if the core of the bubble was even hotter – maybe even as hot as the core of the sun. If so, fusion would happen there. But until Taleyarkhan, no one had been able to either prove it or disprove it.