Studying the Pulsing Sun

The new discipline of helioseismology—analysis of the seismic waves within the Sun—got a boost in 1994, when an instrument developed by NCAR solar physicist Steve Tomczyk was deployed at Mauna Loa. The low-degree, or LOWL, instrument measured the solar surface as it pulses outward and inward, converting those data into low-frequency oscillations. Data showed that the inner two-thirds of the Sun appears to rotate at a constant rate regardless of latitude and depth, while the Sun's outer third differs markedly from its interior.