In 2006, there was a bombshell news in the astronomical community, the International Astronomical Union downgraded Pluto, the original nine planets became eight planets, and Pluto was also redefined as a dwarf planet.
Pluto is a mysterious object located at the edge of the solar system, and was once the ninth planet by default by astronomers, but with the continuous development of astronomy, Pluto's status has undergone subversive changes.
First of all, we have to understand why Pluto was downgraded, in fact, it is inseparable from its orbit and its own reasons, first of all, its orbit, Pluto's orbit is different from the other eight planets, there is a fundamental difference.
The orbit of Pluto is a special elliptical orbit, and it is because of this elliptical orbit that the distance between Pluto and the Sun becomes larger and larger, and this orbit is extremely unstable.
To use an inappropriate analogy, Pluto is like a disobedient and mischievous child, sometimes approaching the sun and throwing himself into its arms, and sometimes running far away, running into the abyss of the universe that no one can find.
And this instability makes Pluto unable to have the same characteristics as other planets, let alone enjoy the heat brought by the sun stably, and instability is the reason why Pluto is downgraded.
In the whole solar system, all the planets revolve around the sun, and each planet plays a different role, moving in a stable orbit and maintaining the balance of the solar system.
However, Pluto is different from other planets, not only has a unique orbit, but also has a reason why it was removed from the ranks of the nine planets, that is, the quality problem.
First of all, let's understand how Pluto was discovered, many people may not know about Pluto, Pluto is the first Kuiper Belt object to be discovered, and it is also the first Pluto-like object.
And it is also the largest and most massive dwarf planet known in the solar system, let's take a look at its location first, Pluto is the fifth closest planet to the sun in the solar system, about 5.9 billion kilometers from the sun.
Because of its unique orbit and the distance between it and the sun, Pluto cannot be illuminated by the sun all the time, so it is also called the star of the underworld, and the reason why Pluto is so cold is because it has a large area of ice on the surface, and the temperature will be particularly low.
Pluto's mass is very small, which is why it is unstable, and after research, Pluto's mass is only 0.002 times that of Earth, so its presence is particularly low in the entire solar system.
And Pluto also has a feature that is different from other planets, Pluto cannot attract surrounding matter, which also makes it unable to form a ring of other planets, which is composed of dust and rock fragments in the universe.
However, Pluto lacks such a substance, so Pluto is unusually special in the planet family of the entire solar system, so Pluto will be downgraded.
The International Astronomical Union has integrated galaxies, redefined the concept of planets, and decided to remove the "unsocial" Pluto from the lineup of nine planets.
According to the new definition of the IAU, if a celestial body wants to get the title of a planet, it must meet three conditions, first of all, the first condition is to orbit the sun, but Pluto is always close to each other, perhaps because of the unique elliptical orbit, it and the sun are far and near, so the first condition is not met.
The second is that it must be almost sphere-like, which Pluto can satisfy, but the fly in the ointment is that it does not have a ring like other planets, but it does not affect it.
The third and most important point is to clear other objects in this orbital area, although Pluto barely meets the first two points, but the third point is not satisfied, you must know that there are still many frozen objects in Pluto's orbit, so that it cannot dominate.
This is the first time that Pluto has been included in the list of dwarf planets since its discovery in 1930, and it was previously regarded as the ninth largest planet in the solar system.
However, with the advancement of science and technology, astronomers felt that it was indeed inappropriate to regard Pluto as the ninth planet in the solar system, so they asked everyone to re-examine it, and eventually scientists redefined the concept of planets.
After the downgrading of Pluto, although it lost the title of the ninth planet, it has not been ignored, a dwarf planet is also worthy of our continued study, as we continue to explore, I believe that one day we can fully understand the secrets of Pluto.