Spectral lines observed in the granules on the Sun's surface near the center of the Sun's disk
A) are split by the Zeeman effect due to the strong magnetic fields in the granule.
B) are always redshifted because granules are caused by gas descending into the Sun.
C) are redshifted near the center of the granule and blueshifted near the edge of the granule.
D) are blueshifted near the center of the granule and redshifted near the edge of the granule.

Question

Quizplus · Accepted Answer

Granules are caused by the rising of hot gas from the Sun's interior and the sinking of cooler gas towards the interior. Therefore, spectral lines observed in the granules are blueshifted near the center (where hotter gas is rising) and redshifted near the edge (where cooler gas is sinking). This effect is known as the convective blueshift. The Zeeman effect can occur in strong magnetic fields but it is not the main cause of the observed spectral line splitting in granules. Option B is incorrect as granules are caused by rising and sinking gas, not just descending gas.

Spectral Lines Observed in the Granules on the Sun's Surface