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This is our solar system.
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Well, it's a model of our solar system.
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Sun at the center and the eight planets that orbit it.
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Wait a second. What's this?
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Pluto?
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What are you doing here, Pluto?
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What?
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Well, don't look at me like that. What do you want me to do?
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You're technically not a planet anymore; you're a dwarf planet.
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But that doesn't mean you're not important.
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Oh, Pluto, your discovery was very important.
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And it led to us learning even more about our solar system.
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Yeah, that's right.
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Let me explain, but let's go back a bit.
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It was the ancient Babylonians that first observed the planets in our solar system.
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They noticed that while most stars stayed in the same position relative to each other, some of them would move around the sky.
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They weren't stars at all; they were planets.
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In fact, the word "planet" comes from the Greek word "wanderer" because they... wandered through the sky.
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At first, we thought there were only five planets: Mercury, Venus, Mars, Jupiter, and Saturn.
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Then, in the 16th century, we realized that Earth was also a planet.
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Yep! Mind blown.
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It was Nicolaus Copernicus in 1543 that suggested the planets revolved around the sun.
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It took a few years to catch on, but eventually, people accepted the idea.
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About 200 or so years later, we discovered Uranus.
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Hey! No jokes, please, Pluto.
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Cheeky.
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Like the other planets, you can see Uranus without a telescope.
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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.
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Then, in 1846, astronomers noticed something weird happening to Uranus's orbit.
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Turns out, it was because of the gravitational pull of Planet Eight, Neptune.
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And that brings us to Pluto.
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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.
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Pluto's discovery made headlines.
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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.
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Then, we spent the next few decades remembering the names of all nine planets in our solar system, until...
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Yep, Pluto, my friend, you were downgraded to a dwarf planet.
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I mean, you are pretty small compared to the others.
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Especially that one.
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And that one.
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And that one.
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Well, all of them, really.
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You're actually smaller than our moon.
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And Australia.
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Yeah, you're pretty tiny.
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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.
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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.
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Awww!
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So, to some of us, you'll always have a special place in our Solar System.
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Just, uh, not this model because, you know, accuracy.
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Yeah.