I have a joke for you:

Why is the moon in such a bad mood? It's just a phase!

A man with a moon head is clapping.

Don't get it? Don't worry! You will soon!

If moon puns don't phase you, you're about to find out why the moon appears to change its shape.

Hold up just a moon-ute!

Sometimes the moon is so bright it lights up the whole sky.

A moon in the clouds lighting up the sky.

And at other times, it looks like a clipped-off fingernail.

A moon that looks like a fingernail.

Is it really changing shape or am I just i-moon-gining it?

You're not imagining it, but it is an illusion.

A man disappears in a puff of smoke.

Another illusion is that the moon emits light. It's actually the sun's light that lights up the moon.

Just like our planet Earth, one side of the moon is fully exposed to the sun's light.

The sun lighting up one side of the moon. Photo by John Doe on pxfuel

  • As the moon orbits (i.e. moves around) Earth, we see more and more, and then less and less, of the parts of the moon that are exposed to the sun's light.

  • When the moon is between us and the sun, we can't see the surface that is exposed to the sun's light, making it seem like the moon has disappeared.

  • And when we on Earth are between the sun and the moon, we can see the entire lit up surface of the moon.

Take a look at the video clip below to see it happening!

How did the moon take the news? It wasn't phased.

The different shapes of the moon are known as its phases.

The moon's phases. Photo by Ramiro Martinez on Unsplash

And what are these phases called?

New Moon 1. New moon: This happens when the moon is between us and the sun and we can't see any of its lit up surface.

Crescent Moon 2. Crescent moon: We can see a small sliver of the moon that is lit up.

Quarter Moon 3. Quarter moon: We can see half of the half of the moon that is lit up.

Gibbous Moon 4. Gibbous moon: Nearly all of the moon appears to be lit up.

Full Moon 5. Full moon: We're between the moon and the sun, so we can see the entire exposed side of the moon.

After this cycle completes, it reverses, starting with the gibbous moon, and the other side of the moon seems to disappear. 🌕 🌖 🌗 🌘 🌑

How does the moon cut its hair? Eclipse it!

Remember how you learned that when the Earth is between the sun and the moon, we see a Full Moon, i.e. the entire lit up surface of the moon, once per month?

Well, there's an exception to this rule.

The Nutty Professor looking surprised.

Most of the time, the moon's orbit is tilted in such a way that the sun's light passes the Earth and hits the moon.

But every now and then, the sun, the earth, and the moon perfectly align and the earth blocks the sun's light from directly hitting the moon's surface.

The sun's refracted (bent) light hits the moon and makes it appear bright red.

This is called a lunar eclipse.

A red moon during a lunar eclipse. Photo by Zoltan Tasi on Unsplash


What prevents a lunar eclipse from happening every month?

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Tired of this lunacy? Catch you lunar!

A moon with a face and legs is walking away.


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