Phases of the moon
Discover why the Moon changes shape in the sky. Watch it orbit the Earth, follow how its lit part evolves, and go through the eight phases, from the waxing crescent to the new Moon. A to-scale view finally shows why solar eclipses are so rare.
Open the resourceQuestions about this 3D model
Why does the Moon appear to change shape?
The Moon does not actually change shape. The Sun lights half of it. As the Moon orbits Earth, we see different portions of that illuminated half: these are the lunar phases.
Are lunar phases caused by Earth’s shadow?
No. Lunar phases depend on the Moon’s position relative to Earth and the Sun. Earth’s shadow is involved in a lunar eclipse, which is a different phenomenon.