When and why was Pluto excluded from the list of planets of the solar system?

Do you know that Pluto is considered a dwarf planet? Why, you will find out after reading the article.

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For many years in a row it was believed that the solar system consists of nine planets. And suddenly, recently, the farthest of them called Pluto lost its status and was called scientists by a dwarf planet. Why did it happen? Let's try to answer this question together.

Opening the planet x

Before getting the name of the ancient Roman god of the underground world, Pluto was conditionally called the planet X - he was able to find the astronomer Clyde Tombo from Arizona in 1930. Since scientists have long guessed the existence of the farthest, ninth planet of the solar system, then, of course, almost all astronomers “hunted” it, pre -calling it to the planet Kh.

When Claid Tombo was lucky to make his discovery (and he had to conduct thorough observations for a year, comparing photographs of the starry sky every two weeks), he was able to point to the celestial body corresponding to the posed requirements. And the employees of the victorious observatory gave the right to give the name of the discovered planet-they held a whole competition on this occasion.

The most successful was considered the proposal of an 11-year-old student from the English Oxford Venice Bernie, who came up with the idea of \u200b\u200bcalling the farthest and colder planet with a diameter less than a lunar name of the ancient Roman god of the underground world.

That is how the ninth planet appeared in our solar system, but at first, scientists could not determine its mass. And only in 1978, after the opening of the largest satellite of Pluto called Haron, the astronomers calculated the mass of the planet, which is approximately 1022 kg (0.0021 from the earth), and its diameter is up to 2400 km (and this is almost like the territory of Russia).

Naturally, Pluto turned out to be a relatively small planet, but in the last century the astronomers considered that there could be nothing else out of Neptune, therefore they left the status of a full -fledged planet behind him.

What is Pluto really?

Science does not stand still, and with its development, astronomers received super -powerful telescopes at their disposal, as well as materials provided by space aircraft.

At first, it turned out that around Pluto, many large (over a hundred kilometers in diameter) of cosmic bodies similar in composition to the planet Kh. Their cluster was called a male belt, which stretches on 55 astronomical units (1 A.E. equal to the distance, equal to the distance. From the sun to the ground) from the sun to the orbit of Neptune.
After a detailed study, it turned out that in the Kuiper belt there are objects that do not differ in size from Pluto. So, in 2005, Erid (having its own satellite), as well as McMak and Haumaa, was discovered. And all these three new planets claimed their place in the solar system, since they were not inferior to Pluto in anything.
At the very beginning of 2006, an automatic interplanetary apparatus “New Horizons” was launched, with the help of which NASA conducted in -depth studies of Pluto and Haron. Only in 2015 did the device reached the goal and took the first pictures of the planet H. It turned out that Pluto was a little larger than Erida in diameter (45 km), although the latter is 27 %heavier.
Pluto is painted in reddish-brown tones that arise as a result of the interaction of methane in its atmosphere with ultraviolet radiation. The planet has a “heart” - a mountain region of Tombo up to three and a half thousand meters, covered with ice. It is believed that snow can fall here, and the ice consists of methane and nitrogen (by the way, the local atmosphere consists of it, which quickly disappears into cosmic distances).

During the time that the planet X makes one complete rotation around our luminaries, the Earth manages to make 248 such revolutions.

What led to a decrease in Pluto's status?

Since the scientists did not dare to add three more open planets to the solar system and bring their number to a dozen (after all, it is not known how many more unknown secrets are fraught with space), the classification of celestial bodies has undergone changes.

In 2006, at the legendary twenty -sixth General Assembly of the International Astronomical Union, it was decided to put up a number of conditions that a full -fledged planet should correspond:

rotate around the luminary in a given orbit (fair for planet x)
not to be someone's companion (there are five of them in Pluto)
to have a mass sufficient for its own gravitational forces to give it a spherical shape (Pluto is a sphere)
with the help of gravity strength, foreign objects, absorbing or pushing them out of the vicinity of their orbit.

It turned out that Pluto, McMak and Erid could not “clean up” their smaller “neighbors” from their path, which means that can be considered only dwarf planetsnot dominant.

Perhaps, over time, astronomers will again receive some more accurate information and revise their decision, but so far Pluto, along with the same small planets, will be counted by the dwarf, and the solar system will remain 8-planetary.