The scientists used "acoustic cavitation," in which sound waves rapidly generate and then collapse bubbles in a liquid, to produce sonoluminescence (bursts of light created by the sound waves).  They employed a liquid containing deuterium (an isotope of hydrogen) and a technique that produced bubbles of very high pressure and temperature.  They claim to have detected excess tritium (presumably formed by fusion of deuterium atoms) as well as neutrons characteristic of a fusion reaction.

Because the results are potentially of great significance and because there are serious questions about the validity of the experiment, Science put the paper through a peer review process even more extensive and painstaking than its usual rigorous evaluation.  Science's editors were also acutely aware of the embarrassing "cold fusion" episode several years ago in which two scientists from the University of Utah announced (without having published a peer-reviewed paper) that they had achieved fusion in a tabletop experiment.  The announcement made front-page news around the world, but their work was quickly discredited since no one was able to replicate their results.

Publication of the "bubble fusion" paper has stimulated controversy throughout the scientific world. Such controversy is the essence of how science progresses.  Other scientists will undoubtedly attempt to repeat the Taleyarkhan et al. experiment.  If they succeed, and if they verify the claim that fusion is occurring, it will open a line of research with tremendous scientific and technological potential.  If they fail . . . well, Taleyarkhan and his colleagues won't get their Nobel prize, but the research may still yield some completely unanticipated and perhaps equally important results along the way.

The links below are intended to help visitors put the bubble fusion experiment in perspective.  In addition to articles about the Taleyarkhan et al. experiment, there are links to information on sonoluminescence, as well as to sources on the methods of science and scientific review and publication, and to some additional background information.

^*In the interest of full disclosure, it should be noted that I am Director of Science & Policy Programs at the American Association for the Advancement of Science,  publisher of Science magazine.  However, the magazine is editorially independent of the AAAS program staff and I am not involved in its publishing decisions. 

Links:
= highly recommended

Articles About the Recent Fusion Experiment
R. P. Taleyarkhan et al., "Evidence for Nuclear Emissions During Acoustic Cavitation," Science, Vol. 295, No. 1868 (2002).  Also includes links to associated features in the same issue of Science.

"Fusion in a flash?" Press release from Science magazine on EurekAlert (March 4, 2002).  Description of experiment by Taleyarkhan et al. for the benefit of the news media.

Katie Pennicott, "Fusion-in-a-bubble sparks controversy," Physics Web (March 5, 2002).  Non-technical account of the article and the controversy surrounding it.

Shankar Vedantam, "'Tabletop' Fusion Report Elicits Mixed Reaction," The Washington Post (March 5, 2002), p. A-1.  One of many newspaper articles on the Taleyarkhan et al. paper. 

Dr. David Whitehouse, "Fusion Controversy Rekindled," BBC News Online (March 5, 2002).

Bob Park, "Bubble Fusion:  A Collective Groan Can Be Heard," What's New (March 1, 2002).  In this weekly newsletter, published (but with a disclaimer for its contents) by the American Physical Society, Park cites conflicting evidence and questions Science's decision to publish the paper.

Sarah Graham, "Tabletop Nuclear Fusion Claims Meet with Skepticism," Scientific American (March 6, 2002).

Erik Baard, "'Science' Magazine: Researchers Claim Tabletop Fusion Success," The Village Voice (March 4, 2002).
 

Background on Sonoluminescence

"New light on sonoluminescence," Physics Web (April 1, 1999).  Background on the phenomenon.

David Knapp, "Sonoluminescence:  An Introduction."  A brief introduction, with links from a scientist at  Lawrence Livermore National Laboratory. 

S. J. Putterman, "Sonoluminescence:  Sound Into Light," Scientific American (February 1995).  NOTE:  This is a large pdf file.  It is fairly technical and recommended for readers with some background in physics.

Scientific American "Ask the Experts."  Andrea Prosperetti of Johns Hopkins University and Lawrence A. Crum of the University of Washington answer the question: "The bubbles produced by ultrasound in water (sonoluminescence) reach extremely high temperatures and pressures for brief periods. Could these conditions initiate or facilitate nuclear fusion, as suggested in the recent movie "Chain Reaction"?" 
 

Background on Scientific Publication and the Scientific Method
Donald Kennedy, "To Publish or Not to Publish," Science, Vol. 295, No. 1868 (2002).  Editorial by the editor of Science explaining his decision to publish the controversial article.

Jose Wudka, "The Scientific Method," part of the instructor's notes from Physics 7 at the University of California, Riverside.  A short description of how science works.

Frank L. H. Wolfs, "Introduction to the Scientific Method," an appendix to notes from physics labs at the University of Rochester.

Anne C. Weller, "Peer Review:  Do Studies Prove Its Effectiveness?" The Scientist (October 29, 2001). ". . . studies providing unquestionable evidence of the value of peer review remain elusive. . ."

National Academy of Sciences, "Publication and Openness," from On Being A Scientist: Responsible Conduct in Research (Second edition, 1995).
 

Other Relevant Information

Oak Ridge National Laboratory, where the experiment was performed.

Home page of Dr. Richard T. Lahey, Jr., second author on the paper.  Lahey is the Edward E. Hood Professor of Engineering at Rensselaer Polytechnic Institute (New York) and former dean of engineering at that institution.  Also see his listing as a member of the National Academy of Engineering.

The Defense Advanced Research Projects Agency (DARPA), a federal government agency which provided support for the experiment.  DARPA "pursues research and technology where risk and payoff are both very high and where success may provide dramatic advances for traditional military roles and missions." 

The Russian Academy of Sciences, collaborating institution in the experiment (in Russian).