Good vibrations from the stars: Our planet rings like a bell after a large earthquake. Stars can ring, too. Astronomers use these vibrations to probe stellar interiors and even estimate the age of the Universe
New Scientist 27 January 1990
ASTRONOMERS and geophysicists share a common handicap. Neither can see directly inside the object they study. The interiors of stars are completely shielded from view: astronomers can see less than 0.01 per cent of our Sun, the star we know best. Most of the Earth is also out of reach. The deepest oil wells and mines barely scratch the surface of our planet. The Earth's core, separated from us by only a few thousand kilometres, might as well be light years away. Despite this, geophysicists have a fairly detailed idea of the internal structure of the Earth, carefully pieced together through seismology, the study of earth tremors. In recent years, the discovery of vibrations on the surface of the Sun and a few other stars has inspired astronomers to adopt a similar approach. This new breed of stellar seismologists hopes to uncover some of the secrets hidden in the centers of stars by using vibration.