Through data from the NASA/ESA Solar and Heliospheric Observatory (SOHO), physicists have discovered a type of seismic wave (g-waves) in the Sun. These low-frequency waves reveal that the sun's core rotates about 4 times as fast than its surface.
Similarly to how scientists use earthquakes to study the Earth's interior, solar physicists use helioseismology to study the Sun's interior structure. However, unlike the Earth, the Sun is constantly 'quaking' - this is due to the convective motions within the Sun's giant body.
Higher frequency waves (p-waves) are commonly detected on the Sun due to sound waves rumbling through the upper layers of the Sun. Conversely, there exists lower frequency g-waves affected by buoyancy (gravity) which have no clear signature at the surface, thus presenting difficulty in detecting them.
The 40-year-old discovery in the making suggests that the solar core rotates once every week, nearly four times faster than the Sun's 25-35 day surface rotation period. “The most likely explanation is that this core rotation is left over from the period when the Sun formed, some 4.6 billion years ago,” said co-author Roger Ulrich, professor emeritus of astronomy at the University of California at Los Angeles.
Read more about this fascinating story at: http://www.sci-news.com/astronomy/suns-core-soho-05092.html
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