Each time you look at the moon it's going to look a little different. Sometimes you'll see the entire moon, other times you'll see just a portion of it.
Why the moon looks the way it does?
The Moon takes about a month to orbit the Earth. The Sun can only shine on half the moon at any given time. Since the moon orbits at exactly the same rate as a spins we only see one side of the Moon from the Earth. The side we don't see is usually called the Far Side of the Moon. You can also call it the Dark Side of the Moon. But it's not always dark so this name can be a bit confusing.
When the moon is closest to the Sun, the side of the Moon facing the Earth is dark. The sunlight reflects off the Earth so we can still see the moon if we look closely. We refer to this as a New Moon.
As the Moon comes around we start to see a tiny sliver of the Moon. This is called the Waxing Crescent.
A few more days pass by and now we can see half the Moon. We can call this A Half Moon but more specifically it's called A First-Quarter, because we are a quarter of the way through the phases.
A few more days and only a small portion of the Moon is not lit up. This is called the Waxing Gibbous.
When the Moon is on the other side of the Earth it is completely lit. This is called A Full Moon and it's probably the phase that you're most familiar with.
Now the light began to fade. We mirror the previous phases. Here's the waning gibbous. The third quarter. The waning crescent and back to a new moon.
Tricks to Remember the Phases
- Waxing means the sunlit portion is increasing.
- Waning means the sunlit portion is decreasing.
- Crescent is where the moon is mostly dark.
- Gibbous is where the Moon is mostly lit.
The Earth is rotating once a day tilted by twenty three and a half degrees.