You know it when you see it, but what makes a full moon full?
Why does the moon seem to change its shape every night? Remember that the moon is a world in space – with a day side and a night side.
A waning crescent moon is sometimes called an old moon. It’s seen in the east before dawn.
A first quarter moon rises at noon and is high overhead at sunset. It sets around midnight.
When you see the moon as a slim crescent – in the west after sunset – it’s a waxing moon. Is that Earth’s shadow on the moon? No, it’s the moon’s own shadow.
A last quarter moon looks half-illuminated. It rises around midnight, appears at its highest in the sky at dawn, and sets around noon.
In the few days after full moon, you’ll often see a waning gibbous moon in the west in early morning, floating against the pale blue sky.
A waxing gibbous moon appears high in the east at sunset. It’s more than half-lighted, but less than full.