Chapter 1. Overview
1.1 Activity: How Big Are Sunspots?
How Big Are Sunspots?
The Sun is the only star whose surface details can be seen clearly using Earth-based telescopes. The layer in the Sun’s atmosphere from which visible light is emitted is the photosphere. more info... There is not a sharp boundary dividing the photosphere from the solar interior that lies beneath it. Rather, the base of the photosphere is where the Sun’s gases become sufficiently opaque to prevent light coming from lower levels to escape. Note that the photosphere appears darker near the limb, or edge, of the Sun; here we are seeing the upper photosphere, which is relatively cool and thus glows less brightly. The dark sunspots are also regions of relatively low temperature. When viewing the Sun, astronomers always take great care to avoid severe damage to their eyes by using extremely dark filters or by projecting the Sun’s image onto a screen. The Sun is so bright that its rays, focused by a lens of an unprotected eye, can destroy the retina and cause permanent blindness. Never look directly at the Sun! (Celestron International)
1.
Consider the photograph of the Sun's photosphere at right and determine the measured horizontal diameter of the Sun in mm using a ruler.
Correct.
2
Incorrect.