Why is Pluto No Longer Considered As Planet?

Pluto (source)

Perhaps many of us first remember that our solar system consists of nine planets, and Pluto is one of them. But then Pluto no longer considered as a planet. Why so?

Pluto was discovered in 1930 by an astronomer, who thought that he had discovered the 9th planet in our solar system beyond Neptune. Pluto's size in our solar system is kinda small, but astronomers on that time believe that Pluto is the 9th planet in our solar system. Then the problem comes when the advanced telescope successfully developed at that time, and from the observations, we know that Pluto is just one of many celestial objects are in the area called the Kuiper Belt. At the Kuiper Belt, there are more than 70,000 celestial objects like Pluto. One of them is Eris that larger than Pluto and makes Pluto's status as a planet is in doubt.

Solar system (source)

Because of many celestial objects like Pluto are out there, making the astronomers finally made the terms for an object sky can be called a planet. The first terms are the object must orbit the sun. The second terms are the object should be a sphere as a mark that the object has a strong enough gravity. And the last terms is the object must be an object with gravity strong enough so the planet can clean other objects from the orbit And is this last terms that poor Pluto can't be fulfilled. Ideally, Pluto must have to clean other surrounding objects to be called a planet. But then, to classify the Pluto-like planets astronomers created a name called Dwarf Planet.

So thanks to Pluto because, before the case Pluto in 2006. We did not have a specific requirement for an object sky can be called a planet. And maybe if it was not because Pluto. Any sphere object is floating in space can we call planets. Finally, thank you for reading.