// Explore the Moon
One Moon, changing phases
Follow the Moon around Earth and compare the view from space with the phase we see in the sky.
Overhead view · above Earth’s north pole
Moon as seen from Earth
New Moon
0% illuminated
The sunlit half faces away from Earth.
North-up view; waxing lights the right side.
Half is always sunlit. Phases change because we see different amounts of the Moon’s illuminated half. Earth’s shadow causes lunar eclipses, not the monthly phases.
Why 29.53 days? The Moon orbits in about 27.3 days, but Earth moves around the Sun too. The Moon needs a little longer to return to the same phase.
Idealized circular orbit in a Sun-relative frame; sizes and distances are not to scale. Orbital tilt, libration, and eclipses are omitted. Surface map: NASA’s Scientific Visualization Studio / LRO. Learn more at NASA.