Celestial acoustic research shows that the sun's outer layers are more sensitive to medium and higher frequencies, indicating that some areas of the solar surface have weakened.
The sun releases sound waves, and like a musical instrument, the structure of the sun informs the way the sound waves are shaped. Scientists can study the sun's oscillations by listening to the frequencies that make up the sound signal, thereby learning something about the object making the sound. Because the waves are generated by and pass through different sections of the sun, the wave frequency reveals clues about the inside of the sun and allows scientists to chart changes in the star's life.
Scientists from the Birmingham Solar-Oscillations Network at the University of Birmingham, in the United Kingdom, used the sun's sound waves to determine that one of its outermost layers may be growing thinner. [How the Sun's Magnetic Field Works (Infographic)]
"The sun is the only star on which we can get this level of detail," Yvonne Elsworth, a researcher working on the project at the University of Birmingham, told Space.com in an email. "Other stars do show activity cycles, and if we can understand the processes in the sun, we will be able to extend the ideas to other stars."