Well, it's a model of our solar system.

Sun at the center and the eight planets that orbit it.

Wait a second. What's this?

Pluto?

What are you doing here, Pluto?

What?

Well, don't look at me like that. What do you want me to do?

You're technically not a planet anymore; you're a dwarf planet.

But that doesn't mean you're not important.

Oh, Pluto, your discovery was very important.

And it led to us learning even more about our solar system.

Yeah, that's right.

Let me explain, but let's go back a bit.

It was the ancient Babylonians that first observed the planets in our solar system.

They noticed that while most stars stayed in the same position relative to each other, some of them would move around the sky.

They weren't stars at all; they were planets.

In fact, the word "planet" comes from the Greek word "wanderer" because they... wandered through the sky.

At first, we thought there were only five planets: Mercury, Venus, Mars, Jupiter, and Saturn.

Then, in the 16th century, we realized that Earth was also a planet.

Yep! Mind blown.

It was Nicolaus Copernicus in 1543 that suggested the planets revolved around the sun.

It took a few years to catch on, but eventually, people accepted the idea.

About 200 or so years later, we discovered Uranus.

Hey! No jokes, please, Pluto.

Cheeky.

Like the other planets, you can see Uranus without a telescope.

Because it's quite dim and moves very slowly, no one really noticed it, until 1781, when astronomer and composer Frederick William Herschel came along and discovered it.

Then, in 1846, astronomers noticed something weird happening to Uranus's orbit.

Turns out, it was because of the gravitational pull of Planet Eight, Neptune.

And that brings us to Pluto.

In 1930, American astronomer Clyde Tombaugh was checking out images he'd taken of the stars and realized one of those specks of light kept moving.

Pluto's discovery made headlines.

Its name was actually suggested by an 11-year-old, who thought it would be cool to name it after the Roman god of the underworld, seeing as Pluto lives in such a cold and desolate part of the Solar System.

Then, we spent the next few decades remembering the names of all nine planets in our solar system, until...

Yep, Pluto, my friend, you were downgraded to a dwarf planet.

I mean, you are pretty small compared to the others.

Especially that one.

And that one.

And that one.

Well, all of them, really.

You're actually smaller than our moon.

And Australia.

Yeah, you're pretty tiny.

Plus, we've found a bunch of other objects in the Solar System that are much bigger than Pluto, but not quite big enough to be planets.

In 2016, we sent this spacecraft to study Pluto, found out it had a bunch of moons, and, best of all, had a big old love heart on its surface.

Awww!

So, to some of us, you'll always have a special place in our Solar System.

Just, uh, not this model because, you know, accuracy.

Yeah.