There are 8 major phases of the Moon. These phases repeat every month as the Moon orbits around the Earth.
The Moon appears to grow and shrink as it passes through its phases.
Why does the Moon have phases?
Have you ever wondered why the Moon has a different shape every night? This happens because it is orbiting around the Earth.
The Moon orbits around the Earth just like the Earth orbits around the Sun. As it moves around the Earth, the Moon’s position in relation to the Sun changes. This affects how much of the Sun’s light hits the Moon.
The Moon has phases that depend on how much light it receives from the Sun.
We are able to see the Moon best at night because it is reflecting the Sun’s light.
Waxing or Waning?
When we talking about the phases of the Moon, we use the terms waxing and waning.
Waxing is a term that means growing. When the Moon is waxing, it appears to increase in size.
Waning means shrinking. Waning phases show a decrease in size.
It takes the Moon about 29.5 days to complete one cycle. One cycle is one orbit around the Earth. During that time, the amount of the Moon that we see from Earth changes. These are the phases of the Moon.
Although it looks different every night, there are 8 major phases that we recognize.
The phases of the Moon get their names from the part of the lunar cycle they fall under.
During this phase, the Moon is between the Earth and the Sun. Because the Sun’s light is not illuminating the part of the Moon facing Earth, we cannot see it at night.
A solar eclipse is only possible during a New Moon.
The Waxing Crescent phase begins the part of the lunar cycle when the Moon is visible at night. This phase gets its name from the crescent shape of illuminated lunar surface. Since it is waxing, the Moon appears to increase in size each night.
A Crescent Moon shows a sliver of the lunar surface.
During this phase, half of the Moon is visible. It is sometimes called the first half-moon. This phase also marks the first quarter of the lunar cycle.
Gibbous is a word that means swollen. The half-moon swells to illuminate much of the lunar surface. Only a sliver of the Moon is dark.
The entire face of the Moon appears to glow. At this phase, the Earth is between the Moon and the Sun but is not blocking any light.
A lunar eclipse is possible during a Full Moon.
Like the Waxing Gibbous, we can see all but a small sliver of the Moon. However, the Moon is waning and begins shrinking.
This Waning Gibbous Moon is about 87% illuminated.
Again, half of the Moon is visible. We see exactly half of the Moon. This phase marks the last or final quarter of the lunar cycle.
The quarter phases are easily recognized because they show half the Moon illuminated.
This is the final phase before the cycle begins again. The Moon appears as a small illuminated crescent.
Occasionally, two Full Moons will occur within the same calendar month. We call this second Full Moon a Blue Moon.
Blue Moons happen once about every 3 years. This makes them rare.
If you’ve heard the expression “Once in a Blue Moon”, it’s the same thing. This saying refers to something that doesn’t happen very often, like a Blue Moon.