Source: Extra Practice
Why do we observe different phases of the Moon, such as a New Moon or a Full Moon?
Options
Option A
The Moon changes its shape periodically.
Option B
The Earth's shadow falls on the Moon, obscuring parts of it.
Option C is correct
We see different portions of the Moon illuminated by the Sun as it orbits Earth.
Option D
Clouds in Earth's atmosphere block our view of the Moon.
Explanation
The phases of the Moon are caused by the changing angles at which we view the Moon's sunlit surface as it revolves around the Earth. The Moon itself does not produce light; it reflects sunlight. As the Moon orbits, the amount of its sunlit side visible from Earth changes, leading to different phases. The Earth's shadow causes lunar eclipses, not the regular phases, and clouds only temporarily obstruct vision.