Final answer:
The phases of the Moon are caused by the Moon orbiting Earth, the Sun lighting different parts of it over time, and varying amounts of the illuminated surface being visible from Earth.
Step-by-step explanation:
The phases of the Moon as seen from Earth are affected by several factors. The primary contributors include:
- The Moon orbiting the Earth, which changes the angle at which sunlight hits the Moon's surface.
- The Sun lighting different parts of the Moon at different times as the Moon revolves around the Earth.
- Varying amounts of the Moon's lit surface being visible from Earth depending on the lunar cycle.
As the Moon orbits Earth, we observe different portions of its daylight side, leading to the varying phases, from new moon to full moon and back again. This cycle is due to the relative positions of the Earth, Moon, and Sun.