Waves help reveal the Sun's secrets

Astronomical figures provide rays of hope

Applied mathematics has proved a key research tool in investigating the mysteries of the Sun.

It has been known for about two decades that the Sun is an oscillating sphere, vibrating like a bell that has been struck. Bernard Roberts, head of applied mathematics and of the solar theory group at St Andrews University, pioneered the theory eight years ago that these oscillations would vary over time as a consequence of the Sun's magnetism.

Measurements from the Soho (Solar and Heliospheric Observatory) space mission over the next few years will explore these variations in the oscillations.

"These oscillations are a diagnostic tool," Professor Roberts said. "They tell us what's happening beneath the Sun's surface, just as a seismologist can figure out what happens beneath the surface of the earth from the waves in the earth's crust from an earthquake. It's the only way we'll learn about the interior of the Sun or any star, because you can't see below the surface - you can just see light from the surface."

He is interested in how magnetic waves occur in the Sun. Such waves could explain why the Sun's atmosphere is far hotter than its surface. The Sun is in a "well-behaved" stage, but it will go into a more active phase by the millennium, allowing theories of the effects of magnetism on the oscillations to be tested.