Oscillating Sun

Although the Sun is a big ball of gas undergoing nuclear fusion in the core, it can also be thought of as a large bell that is constantly being struck. In the outermost layers of the Sun's interior, pressure waves get generated. Pressure waves are another name for sound waves, and these get reflected back from the surface, into the Sun. These waves get refracted as they travel into the Sun, so they will get to different depths. By studying the different frequencies of pressure waves, it is possible to learn about the interior of the Sun, similar to the way we learn about the Earth's interior by studying the shock waves from earthquakes.

Solar astronomers from Birmingham have been studying the doppler shifts - how fast something is moving towards or away from us - and hence oscillations, in the surface of the Sun since the 1970s. The Birmingham Solar Oscillations Network (BiSON), who have six telescopes around the world constantly monitoring the Sun, now have almost 30 years worth of observations of oscillations. With data covering almost three solar cycles, they hope to be able to look for long term changes between cycles.

Posted in astro blog by Stuart on Thursday 07th Apr 2005 (00:47 UTC) | Permalink
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