what are the phases of the moon

The Moon has eight main phases, repeating in a cycle that lasts about 29.5 days: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third (last) quarter, and waning crescent.

Quick Scoop

• New moon – The side of the Moon lit by the Sun faces away from Earth, so the Moon looks invisible in the night sky.

• Waxing crescent – A thin crescent of light grows on one side of the Moon as more of the lit side becomes visible.

• First quarter – Half of the Moon’s face looks lit (a “half moon”); the Moon has gone about one-quarter of the way around Earth.

• Waxing gibbous – More than half but not all of the Moon is lit as it heads toward full moon.

• Full moon – The entire face of the Moon that we see from Earth is lit, forming a bright circle in the sky.

• Waning gibbous – After full moon, the lit part starts to shrink, but more than half is still illuminated.

• Third (last) quarter – Another “half moon,” when the Moon is three-quarters of the way through its orbit and the opposite half is lit compared with first quarter.

• Waning crescent – Only a thin crescent remains before the cycle returns to new moon.

These phases happen because the Moon orbits Earth while sunlight always illuminates half of the Moon; what changes is how much of that lit half we can see from Earth.