Believe it or not, a tank of cleaning fluid buried underground is telling us about what goes on at the center of the Sun. and the startling news is that the Sun may have stopped burning, albeit temporarily.
According to theory, the nuclear reaction include the Sun should produce atomic particles known as neutrinos, which escape directly into space and reach the Earth. Neutrinos are difficult to detect, but some of them can be captured by chlorine atoms. A good source of chlorine is the liquid called perchloroethylene, which is used in dry cleaning.
An American scientist, Raymond Davis, has set up a tank of 400,000 liters (88,000 gallons) of this dry-cleaning fluid in a gold mine in South Dakota. It is placed 1.5 km underground to shield it from other forms of radiation. The experiment has detected far fewer neutrinos coming from the Sun than astronomers expected. One possible reason is that the Sun’s nuclear furnace needs stoking.