Phases of the Moon
Sun
Lighted Side
Dark Side
Moon Earth
Day
Night
Moon’s Orbit
Earth–Moon Relationship
• The Moon revolves around the Earth every 29 ½ days!
• The Moon also rotates on its axis every 29 ½ days.
Sun
Lighted Side
Dark Side
Moon Earth
Day
Night
Moon’s Orbit
Because of that, the same side of the Moon faces the Earth as the Moon revolves around the Earth.
Earth–Moon Relationship
The Moon Phases
The shape of the Moon appears to change
Waxing Moons
• The Moon appears to grow or get bigger
• The Moon phases starting at the New Moon and ending at the Full Moon
New Moon Waxing Gibbous
1st QuarterWaxing Crescent
Full Moon
Waning Moons
• The Moon appears to be getting smaller or disappearing
• The moon phases starting at Full Moon and ending with the New Moon
Full Moon Waning Crescent
3rd or Last Quarter
Waning Gibbous
New Moon
EarthEarth Sun
New Moon
No Moon is visible in the night sky.
What we would see at night on Earth – no
moon!We can’t see the moon at
night because it is on the
other side of the Earth
New Moon
Waxing Crescent
A small sliver on the right side of the Moon is visible just after sundown.
What we would see at night on Earth
This is the angle the moon is
viewed from
Earth Sun
Waxing Crescent
1st Quarter
Earth
Looks like half of the Moon, but you are really seeing only a quarter.
What we would see at
night on Earth
This is the angle the moon is
viewed from
SunEarth
1st Quarter
Waxing Gibbous
Earth
The lighted side has bulged out; visible in the evening.
What we would see at night on Earth
This is the angle the Moon is
viewed from
Earth Sun
Waxing Gibbous
Full Moon
Earth
Very bright; you can see all of the lighted side of the Moon.
Earth Sun
What we would see at night on Earth
This is the angle the Moon is viewed from
Full Moon
Waning Gibbous
Earth
The lighted side is now on the left side; visible in the early morning.
What we would see at
night on Earth
This is the angle the Moon is
viewed from
Earth Sun
Waning Gibbous
3rd (Last) Quarter
Earth
Opposite image of 1st Quarter
What we would see at
night on Earth
This is the angle the Moon is
viewed from
Earth Sun
3rd (Last) Quarter
Waning Crescent
Earth
A small sliver of the Moon is visible just before dawn.
What we would see at night on
Earth
This is the angle the Moon is
viewed from
Earth Sun
Waning Crescent
Earth Sun
Why We See Moon Phases
Earth
The shape of the Moon appears to change due to the angle at which the lighted side is seen from Earth.
EarthEarth Sun
1st Quarter
Waning Gibbous
Full Moon
Waxing Crescent
New Moon
Waning Crescent
3rd (Last) Quarter
Waxing Gibbous
Why We See Moon Phases Animation
The Phases of the Moon