Why Is Pluto No Longer a Planet?

For a long time, Pluto was the ninth planet. But in 2006, scientists decided it did not quite fit the team. They changed its job title to dwarf planet.

Imagine you are cleaning your room. If you put all your toys in one big pile, they look like a group. But if there is one tiny toy truck stuck under the bed while five giant trucks sit outside, that little truck is doing its own thing. Pluto is like that toy truck.

To be a full planet, an object must do two things. First, it must go around the Sun. Second, it must be heavy enough to be round. Third, and most importantly, it must clear its neighborhood. This means it is so big or has been around so long that it has swept up or pushed away all the other space rocks near its path.

Pluto fails this third rule. It lives in a crowded street called the Kuiper Belt. There are many other icy objects of similar size wandering past it. Because Pluto shares its road with these neighbors, it is not the boss of its zone anymore. So, it got demoted, but it did not disappear! We still count it as a very special planet-like object.