(1) Both solar and lunar eclipses are caused by the linear propagation of light.

A solar eclipse is when the moon blocks the light from the sun to the earth, so we cannot see or can only see part of the sun; a lunar eclipse is when the earth blocks the light from the sun to the moon, so we cannot see or can only see part of the moon.

(2) During a solar eclipse, the moon blocks the sun’s light from reaching the earth.

The moon is between the sun and the earth.

During a lunar eclipse, the earth blocks the sun's light from the moon.

The earth is between the sun and the moon.

Images of a solar eclipse: Images of a lunar eclipse: