Scientists have been measuring stars by monitoring their "singing ability". Researchers at the University of Birmingham have observed the natural pulse of the light waves emitted by stars and translated the variations in brightness into ringing vibrations, or oscillations, using a technique known as asteroseismology. Bill Chaplin, reader in solar and stellar physics, said: "Stars ring or vibrate like musical instruments. If you measure the pitch of an instrument, you can tell how big it is - the bigger the instrument, the lower the pitch and the deeper the sound. We find that as stars get older, they go through a state where they become less tuneful."