How terrible is Pluto? It is kicked out of the "Nine Planets", but it is not wrong at all

2021-04-06 | Zhong Ming talks about science Original |

Everyone knows that there has always been a popular name for the planets of the sun: nine planets. The nine planets at that time were Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, starting from the closest to the sun.And Pluto. On August 24, 2006, the International Astronomical Union decided through a meeting to kick Pluto out of the nine planets and downgrade it to a dwarf planet. Since then, the nine planets have become eight planets.

Then the question comes, good Pluto, why should you kick it? Not only that, because Pluto itself has many characteristics that are incompatible with the other eight planets, many people say that Pluto is a "weird celestial body" in the solar system.", it is also a "terrible celestial body." Then why is Pluto so strange and so terrible?

Planet X: Pluto

The discovery of Pluto was later than other planets. In 1840, the mathematician Levier predicted the existence of Neptune through Newtonian mechanics theory, relying only on paper and pen. This also inspired many scholars to study whether there are other planets.At that time, a businessman Rowell was also very interested in astronomy. In 1906, he began to search for the ninth planet that might exist: Planet X.

Until 1930, the astronomer Clyde Tombaugh found this "moving celestial body" in the photo, which is Pluto. As soon as the news came out, the whole world was shaken, and everyone gave the ninth star together.Name the planet. An 11-year-old schoolboy from Oxford, England, Venetia Bernie, suggested that the planet should be named after Pluto, the Pluto in classical mythology, and the astronomers finally approved the name "Pluto" unanimously.

However, in subsequent observations and studies, astronomers discovered that this celestial body is becoming more and more strange, with characteristics that are quite different from other planets. First of all, the revolution and rotation of Pluto are very different from other planets in the solar system.The orbits of other planets in the solar system are close to a circle and are also very close to the ecliptic. Pluto has a very high eccentricity and is completely elliptical.

At the same time, the orbit is highly inclined, like a protruding piece on the ecliptic plane of the solar system. Its orbit is at an angle greater than 17° relative to the ecliptic plane. Let alone the strange orbit, the more important thing is that Pluto’s orbit is chaotic.It means that as long as there is a slight change, we can't simulate the change of Pluto's orbit.

This is something other planets do not have. You must know that the planets discovered before can be described by Newtonian mechanics, so Neptune can be predicted by mathematicians with paper and pen. But Pluto is a special case, it is difficultUse Newtonian mechanics to predict its position.

Except for revolution and rotation, Pluto’s satellites are also different from others. It and its satellite Charon are directly locked by the tide, which means that Pluto always has one side facing Charon, and Charon always uses one.Facing Pluto.

In the solar system, no planet has been locked by the tide by its own satellite. The main reason here is that Pluto is about the same size as Charon, so it is easy to be locked by the tide, and other planets are much larger than its own satellite.

Of course, not only these, but Pluto has "very weird" characteristics, which have always challenged the bottom line of astronomers. In 2006, the unmanned probe New Horizons was tasked with exploring this "weird celestial body".

It wasn't until 2015 that the distance to observe Pluto was reached. It took a lot of photos of Pluto, allowing astronomers to begin to understand the "terrible" of Pluto.

Because Pluto is too far away from the sun, reaching 40 times the distance between the sun and the earth, there is almost no solar radiation here. The temperature of the earth's surface is only minus 229 degrees, which is much lower than other planets in the solar system.

In addition, they also found that Pluto is mainly composed of solid nitrogen, and there is also some formaldehyde and carbon monoxide. If humans set foot on this planet, they must be frozen and brittle immediately, which can be called purgatory.

Why will Pluto be demoted?

In 2005, the discovery of Eris completely changed the fate of Pluto. This is because Eris is 27% larger than Pluto. If Pluto is to be considered a planet, then Eris must also be a planet.

The question is, if many celestial bodies with the same mass as Pluto are discovered in the future, should they also be included in the ranks of planets?

Faced with such a situation, astronomers have to rethink the "definition of planets." Therefore, they have redefined the planets. There are three things:

The planets must revolve around the sun;

The mass of the planet must be so large that it can constrain itself into a sphere-like body through its own gravity;

The planet can clean up other celestial bodies in its orbit.

The first two, Pluto and Eris meet the requirements, and the third, because there are many other celestial bodies in their orbits, they do not meet, and the remaining eight planets actually meet this one.Therefore, Pluto and Eris were downgraded to dwarf planets, and the remaining eight planets continue to be called planets.


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