When viewing the Sun's disk in visible light, one sees less deeply into the Sun near the limb than at the center of the disk because of the interaction of the light with atoms of the gas. What conclusion can be drawn from the observation that the Sun appears less bright near the limb than it does at the disk center?

Question

Quizplus · Accepted Answer

The observation that the Sun appears less bright near the limb than at the disk center is due to the effect known as limb darkening. This occurs because light from the limb has to travel through more of the Sun's atmosphere, where the gas is cooler compared to the deeper, hotter layers seen when looking directly at the center. This results in the limb appearing less bright, indicating that the temperature of the gas falls with increasing height in the solar atmosphere.

When Viewing the Sun's Disk in Visible Light, One Sees