In this picture (left) MDI results for outer layers are combined with VIRGO results for the deep interior. Red areas are hotter and blue are cooler than expected.
Virgo observes oscillations in the Sun's brightness due to the internal sound waves. Sound speeds deviate most from theoretical expectations in the level (red) where the turbulent outer region of the Sun meets the calmer interior.
Whole-Sun frequencies by GOLF (right). These frequencies are remarkably free from background noise, especially at the lower frequency range. From these frequency measurements, scientists can deduce very precisely the thermodynamic conditions in the core of the Sun. (Background picture by EIT.)
