Debates continue to rage among cosmologists over whether the planet's definition should be changed.
It was after Pluto was considered the ninth planet after the Sun that it was later removed from the category of planets, but it continues to show various signs that make it questionable about the category it is in.
In 2006, the International Astronomical Union (IAU) voted on the definition of a planet.
At that time, Pluto does not yet meet the requirements to be a planet, making it classified as a 'dwarf planet', which you can compare with other objects in the universe that are going to look like a planet but do not meet all the requirements to be called a planet.
Since then other changes have been observed on Pluto, leading some researchers to wonder if it is time for the planet's definition to change.
In general, there is no fixed definition of a planet, and cosmologists often use their most arbitrary definitions.
As in ancient Greek times, a planet was defined as a star moving through the universe, where the Moon and the Sun were also considered planets.
During the "Copernican revolution" when the study of the universe began to be based on the Sun instead of the Earth, the Moon was removed from the category of planets, made a 'satellite'.
The Earth was then considered a planet, and the Sun was placed in the highest category because it was the one that became the basis of research in the universe.
That's why what researchers have seen today is interpreted based on the area where the planets are located (Solar System), either by showing their distance or their shape and the effects they would have.
This went on for about 200 years, until the Englishman of German descent, William Herschel, discovered Uranus; and the Italian Giuseppe Piazzi discovered Ceres, which was the largest of the series of asteroids located between Mars and Jupiter.
To begin with, Uranus and Ceres were treated as planets. As more and more objects in the universe were discovered to be in transit with Ceres, researchers reconsidered, finding the planets to be habitable on their own.
Herschel suggested that the small objects between Mars and Jupiter should be considered asteroids, while Uranus should be considered a planet.
However, his theory was criticized by some researchers who thought that Herschel's name would remain strong as the discoverer of Uranus.
Researchers continued to follow these steps until the American Clyde Tombaugh discovered Pluto in 1930.
Only this new planet did not have a fixed path through the universe, and it was very small compared to other planets.
It is something that has led researchers to wonder if they should re-evaluate how the universe is classified. Since the 1990s, researchers have begun to see more objects in the Universe that cross the same path as Pluto.
In 2005, the American Mike Brown discovered Eris, a 'dwarf planet' similar in size to Pluto, passing through the path behind Neptune.
It soon became the cause of much controversy over the classification of Pluto as a planet. It made the researchers who gathered in Prague in the Czech Republic in 2006 decided to combine ideas and show the correct definition of what is called a planet.
One group of these researchers demanded that the planets be observed visually, and the other demanded that the planets be examined for their composition or characteristics.
Those who demanded that the planets be defined on the basis of their appearance, argued that a planet should be anything large enough and round in shape.
Their friends said that a planet should be anything that can dominate the way it travels through the universe, and that it can take advantage of all the other things that are in it.
That explanation could have made Pluto, Ceres and other orbits in the same orbit as Pluto all become planets; but all the discoveries in the universe would not be in that category.
It was finally decided that these two definitions of the two sides would be included in the definition of the planet.
Because Pluto did not move in other ways that benefit us from the small things in the way it goes around and makes it go around with a lot of things, it was concluded that it is not considered as a planet.
However, not all researchers agree with the definition adopted at the meeting, which has led to the continuation of the debate that continues to this day.
The words that say something 'is like a wheel' and say that it 'picks up other small things in the way it goes around' are not understood.
However, those who support these two points say that all the planets, from Mercury to Neptune, have a circular shape.
While most of the planets are in doubt, they are not round.
By measuring the orbit of the planet, it is shown that Mars is 5,000 times larger than what you would consider the planet's orbit.
However, Pluto's size covers only 7% of its orbit, which clearly shows that there is no real difference between it and other objects that pass through it.
