Why does the Moon change its shape?

The Moon does not actually change its shape. What we observe are different portions of its illuminated side, known as lunar phases.

Here’s what causes this effect:

• The Moon orbits the Earth
• The Sun always illuminates half of the Moon
• As the Moon moves, the angle between the Sun, Earth, and Moon changes

Because of this changing angle, we see varying amounts of the lit portion from Earth.

These phases follow a regular cycle:

• New Moon (not visible)
• Crescent Moon
• First Quarter
• Gibbous Moon
• Full Moon (fully visible)

This complete cycle takes about 29.5 days, known as a lunar month.

Clear takeaway:
The Moon’s “changing shape” is an illusion caused by its position relative to Earth and the Sun, not an actual physical change.