ELI5: Explain Like I'm 5

How I Killed Pluto and Why It Had It Coming

Once upon a time, Pluto was a planet that we learned about in school. But as we got older and learned more about space, we found out that Pluto was actually quite different from the other planets in our solar system.

You see, Pluto is much smaller than the other planets and it has a very long, elliptical orbit that sometimes takes it closer to the sun than Neptune. It also shares its orbit with other small objects in the Kuiper Belt.

Scientists realized that Pluto wasn't really like the other planets in our solar system, and so they decided to reclassify it as a "dwarf planet" in 2006.

Now, why did Pluto have it coming? Well, it's not that Pluto did anything wrong, but rather that our understanding of what a planet is had changed. We realized that just being round and orbiting the sun wasn't enough to be considered a planet.

Instead, planets need to have cleared their orbit of other debris and be one of the largest objects in their orbit. Pluto didn't do this, and so it didn't fit the definition of a planet.

So, while it may be sad that Pluto isn't considered a planet anymore, we can still appreciate it for the interesting and unique object it is in our solar system.