Music from the Stars

Sounds produced by stars are helping astronomers find out more about their internal structure.

Courtesy of Don Kurtz

A graphical representation of resonating sound waves in the interior of a star similar to the Sun.

Thinking of stars as giant musical instruments is proving to be a useful technique for finding out what they look like on the inside. On December 27, 2006, the COROT spacecraft was launched on a mission that will use asteroseismology – the study of vibrations that are generated from deep within a star – to determine the age, mass and chemical composition of a variety of stars. Past research in this branch of astrophysics has proved that stars pulsate and even produce unique musical sounds – now it is the most precise way of determining a star’s inner structure.

Singing stars?

The idea of singing stars, or the Music of the Spheres, was proposed by Pythagoras more than 2,500 years ago. He claimed that the universe was based on harmony, and that the spinning of planets and stars created music that only the Gods could hear. Mythology turned into science when the field of asteroseismology took off in the 1970s. Astronomers found that stars do pulsate, and are not stabilised by their strong magnetic field as was previously thought.

In fact, this idea is just an extension of the study of seismology on Earth. By examining earthquakes and waves that move through the Earth, scientists have determined the internal structure of our planet. Professor Don Kurtz, a leading expert in asteroseismology from the University of Central Lancashire in the UK, says that after an earthquake, the Earth rings like a bell and the analysis of sound waves that resonate through the planet have allowed scientists to determine that it has a molten iron core, the depth of its mantle and that its internal temperature is 6,000 C.