The physicist who claimed to have observed nuclear fusion in a beaker of acetone two years ago has published new data to back up his claim. Rusi Taleyarkhan, now at Purdue University in Indiana, and colleagues say that fusion neutrons and tritium are produced when the acetone is subjected to intense sound waves in a table-top sonoluminescence experiment (R Taleyarkhan et al. 2004 Phys. Rev. E 69 036109). However, other physicists continue to doubt the experiment.