Watch the Moon orbit Earth and see each phase change. Click any phase to learn more, then test yourself in Quiz mode!
The Moon doesn't produce its own light — it reflects the Sun's light. As the Moon orbits Earth over 29.5 days, we see different portions of its sunlit side. This gives us the 8 phases we recognize.
Waxing means the visible portion is growing (New → Full). Waning means it's shrinking (Full → New). A handy trick: if the bright side is on the right (D-shape), it's waxing. If it's on the left (C-shape), it's waning!