Without a solid surface, the Sun constantly churns and writhes. Sixty years ago, scientists discovered choppy waves, or oscillations, on the surface of the Sun that move up and down with periods – the time between each wave peak – of only about five minutes. Now, scientists have discovered much more slowly oscillating swells in the Sun’s surface, with periods comparable to the Sun’s 27-day rotation.
The discovery, reported on July 20 in the journal Astronomy & Astrophysics, was made with a decade of observations from NASA’s Solar Dynamics Observatory. The observations revealed huge swirling waves moving on the solar surface, which extend 125,000 miles below the surface of the Sun. Computer models showed the waves are caused by the Sun’s rotation, which is faster at the equator than the poles.
The waves are giving scientists a new window into the solar interior, where large-scale motions create the Sun’s magnetic field in a process called the solar dynamo. The solar dynamo is thought to be responsible for the features and eruptions on the Sun’s surface which vary in intensity over the 11-year cycle of solar activity.
Read more about the discovery here.
By Mara Johnson-Groh
NASA’s Goddard Space Flight Center, Greenbelt, Md.