AFOQT Practice Test

What is the primary reason for a lunar eclipse?

1. The moon's proximity to the Earth

2. The Earth's position between the sun and moon

3. The sun's position behind the Earth

4. The moon's reflection of the sun's light

The correct answer is: The Earth's position between the sun and moon

The primary reason for a lunar eclipse is that the Earth is positioned directly between the sun and the moon. When this alignment occurs, the Earth casts its shadow on the moon, blocking sunlight from reaching it. This phenomenon can occur only during a full moon when the sun, Earth, and moon are in a straight line. Consequently, the moon passes into the Earth’s shadow, leading to the observable darkening or reddening of the moon's surface during the eclipse. The other options do not accurately describe the main cause of a lunar eclipse. The proximity of the moon to the Earth does not directly lead to an eclipse; it is more about alignment. The sun being behind the Earth does not cause the eclipse itself; rather, it's the Earth that obstructs sunlight. While the moon reflects sunlight, its reflection is not responsible for creating a lunar eclipse; eclipses depend on the alignment of the Earth, moon, and sun.