A claim by a team of engineers at Oak Ridge National Laboratory that they have achieved nuclear fusion inside tiny bubbles has been met with a wave of skepticism and criticism of the scientific journal that released the results Monday.
The team says it has created a form of nuclear fusion by zapping tiny bubbles of acetone with intense sound waves, causing the bubbles to expand massively and then implode. The imploding bubbles briefly created temperatures hotter than the surface of the sun, enough to cause hydrogen atoms to fuse together into atoms of helium, the researchers contend.
Nuclear fusion, the reaction that fuels the sun and the hydrogen bomb, releases massive amounts of energy. Harnessing that power--and creating it in a laboratory using cheap raw materials--is the goal of many engineers and physicists who say fusion might one day provide a clean and almost limitless source of energy.
Memories of 'Cold Fusion' Shape Response
But claims that scientists have achieved fusion labor under a cloud of suspicion. In 1989, two scientists at the University of Utah said they had found a way to extract energy from room-temperature water--cold fusion. Their claim was quickly disproved after a monthlong frenzy of news conferences, wild claims and sudden retractions. The episode is one Caltech physicist David Goodstein now calls "science gone berserk."
The idea that energy can be extracted from bubbles is not controversial by itself. In the 1930s, German scientists discovered that bubbles pummeled by sound waves would implode and emit energy in the form of flashes of light. The phenomenon, called sonoluminescence, has intrigued physicists ever since; a full explanation of the phenomenon remains elusive.
Scientists at the University of Washington and at UCLA have extended the finding recently, pushing single bubbles to emit light with each pulse of sound and concentrating the amount of energy within tiny bubbles by trillions of times so they build up remarkably high pressures and temperatures.
"When the bubble is collapsing, the temperature at the surface is much hotter than the surface of the sun," said Seth J. Putterman, a physicist at UCLA who has studied sonoluminescence for two decades. "Because the inside of the bubble can get even hotter, people have thought this could be an ideal candidate to see if there is fusion inside."
