Star in the Jar

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In the current setup, creating sonoluminescence takes far more energy than the bubble collapse gives off, even if fusion is taking place, Taleyarkhan says. However, sonoluminescence flashes typically occur at temperatures of thousands of degrees, not millions. “Such high temperatures are unlikely to occur” in the bubbles of the Oak Ridge setup, notes Lawrence A. Crum of the University of Washington in Seattle. Under extreme pressure and at temperatures of millions of degrees, such as at the center of the sun, deuterium atoms fuse in a reaction whose products include tritium–hydrogen’s radioactive heavy isotope–and neutrons.

He is already thinking about his next project. “I was thinking that maybe I could make a hand-held laser cutter,” says Edwards. “So I’ve been looking into some really high-powered lasers.” D. F. Gaitan, (1990) An experimental investigation of acoustic cavitation in gaseous liquids, Ph. D. thesis, Univ. of Mississippi; Gaitan, D. F. et al. (1992) Sonoluminescence and bubble dynamics for a single, stable, cavitation bubble, J. Acoust. Soc. Am. 91, 3166–3183.Bristling at comparisons to the cold-fusion drama, the Oak Ridge researchers say that their findings withstood extensive peer review before being published. The cold-fusion claim in 1989 was announced to reporters before being submitted for publication.

The basis of the new energy source would be so-called sonoluminescence–a phenomenon in which bubbles of vapor in a liquid bombarded by sound waves rapidly implode, generating heat spikes and flashes of light in the bubbles (SN: 10/6/01, p. 213: Shrimps spew bubbles as hot as the sun). Taleyarkhan and several of his Oak Ridge colleagues collaborated on the research with scientists from Rensselaer Polytechnic Institute in Troy, N.Y., and the Russian Academy of Sciences in Ufa. A group of scientists claims to have found evidence of nuclear fusion in a vase-size flask of liquid. The researchers say they created tiny bubbles that seemed to have collapsed with enough violence to force atomic nuclei to fuse. BUBBLE MAGIC. In a flask of acetone bombarded by sound waves, a cloud of bubbles (arrow) briefly swells to the size of a pea before collapsing. Courtesy of Oak Ridge Natl. Lab., Rensselaer Polytechnic Inst., Russian Acad. Sci. THE BIG SQUASH. A neutron pulse (arrow) combines with a sound signal (blue) in a flask of acetone to generate the conditions for a bubble (brown) to form, grow, and then implode with great force. After Taleyarkhan et al./Science Fusion is a problem best solved by the peoples of all nations working together, since the entire world will benefit from it." The new signs of fusion in bubbles were so extraordinary that Lee L. Reidinger, the Oak Ridge lab’s deputy director for science and technology, commissioned two of the lab’s nuclear physicists, Dan Shapira and Michael J. Saltmarsh, to monitor the sonoluminescence setup using different detectors.They just don’t have the evidence,” says William C. Moss of Lawrence Livermore (Calif.) National Laboratory, one of several sonoluminescence specialists who have theorized that fusion in collapsing bubbles is feasible.

If nothing else, [Justin Atkin] is persistent. How else do you explain a five-year quest to create sonoluminescence with simple tools?

Barber, B. P. and Putterman, S. J. (1991) Observation of synchronous picosecond sonoluminescence, Nature 352, 318–320; The measured pulse width is less than 50ps. On the other hand, scientists have produced tabletop fusion, for instance by zapping small clusters of atoms with high-powered lasers (SN: 3/27/99, p. 196: https://www.sciencenews.org/sn_arc99/3_27_99/fob1.htm). In the new work, Taleyarkhan and his collaborators used bursts of neutrons to fabricate clouds of short-lived, but extraordinarily large, sonoluminescence bubbles in acetone, the solvent in many nail-polish removers. In some tests, the researchers filled the flask with ordinary acetone, whose molecules each contain six hydrogen atoms. In other tests, they used deuterated acetone, in which deuterium atoms replace the hydrogen ones.