  According to the recent revision of the theory of thermal radiation, thermal
black-body radiation has an induced origin. We show that in single-bubble
sonoluminescence thermal radiation is emitted by a spherical resonator,
coincident with the sonoluminescing bubble itself, instead of the ensemble of
elementary resonators emitting thermal black-body radiation in the case of open
gaseous media. For a given wavelength, the diameter of the resonator is fixed,
and this explains the very high constancy in phase of light flashes from the
sonoluminesing bubble, which is better than the constancy of period of a
driving acoustic wave.
