Why do you think lunar eclipses can be seen from a large part of the Earth when they happen, but total solar eclipse can be seen by only a small part of the Earth?
A lunar eclipse can be seen from a large part of the Earth because the Earth is much larger than the Moon, so the Earth's shadow cast on the Moon is large enough to cover the entire Moon.
Anyone on the night side of Earth where the Moon is visible can observe the lunar eclipse.
In contrast, during a total solar eclipse, the Moon's shadow falls on only a small area of the Earth's surface because the Moon is much smaller than the Earth.
The Moon's shadow covers a limited region, so only observers within that small area can witness the total solar eclipse.
Explanation
The chapter explains: 'The shadow of the Moon falls on a small area on the surface of the Earth as seen in Fig. 12.13. This area is in total darkness, and no part of the Sun can be seen from there.' For lunar eclipses, it states: 'On such days, we see the Earth's shadow falling on the full disc of the Moon.' The difference in visibility arises from the relative sizes of the shadows cast—the Earth's large shadow on the small Moon versus the Moon's small shadow on the large Earth.
Solution Steps
The Earth is much larger than the Moon, so the Earth's shadow cast on the Moon is large enough to cover the entire Moon.
Anyone on the night side of Earth where the Moon is visible can observe the lunar eclipse.
During a total solar eclipse, the Moon's shadow falls on only a small area of the Earth's surface because the Moon is much smaller than the Earth.
Only observers within the small area covered by the Moon's shadow can witness the total solar eclipse.