Like why is it not included in solar system i don’t get it
The basic answer is that since we’ve discovered Pluto, we have also discovered hundreds of other tiny planets in our solar system that are around the same size as Pluto.
If we keep Pluto as a planet, we then have to add hundreds more planets to our official list. Many scientists feel that’s just not a good idea, and felt that we should instead move Pluto to a different category along with the rest of those tiny planets we found.
The short answer is that it does not in any way dominate the region of space that represents it’s orbit around the sun. It’s not the biggest thing in it’s orbital path. It crosses Neptune’s orbit during it’s journey around the sun.
We have also discovered many other bodies like Pluto. If we call Pluto a planet, we have to call all those things planets, too.
In 2005 astronomers discovered another one, an object now called Eris.
And then another.
It quickly became apparent that there’s a vast sphere of these glorified comets out there in all sorts of wacky orbits. Pluto isn’t even the biggest one.
So this raised a conundrum – do we add dozens of new planets every few years when another wayward ice ball crosses a telescope, or does Pluto get demoted?
Eventually we decided to redefine “planet” to exclude Pluto because it obviously hasn’t cleared all the junk out of its orbit.
It is part of the solar system. But there is more in the solar system than just planets. There are also thousands of large asteroids, hundreds of thousands of comets.
And in the case of Pluto, several relatively small icy bodies, far out in the solar system. We decided that those things should not be called planets, but instead made the new designation “dwarf planet” for anything that fit that description closely, including Pluto.
So, in the 19th century, we discovered a new planet between Mars and Jupiter called Ceres.
However, over time, we started discovering a ton of other, similar objects, around the same orbit. We discovered so many that we realized it didn’t make any sense to call them all planets so we classified them differently. They’re asteroids and comprise the asteroid belt.
Pluto is essentially the same story. We discovered more and more objects out there and that Pluto is just one of very, very many objects in what is now called the Kuiper belt. It makes more sense to consider Pluto a dwarf planet among many objects in the Kuiper belt rather than a planet akin to the others.