Have you ever heard that there are 9 planets in our solar system? Yes, it was the time when Pluto was known as a planet. Surprisingly, experts claimed that Pluto was no longer a planet in 2016. You may be curious what are the reasons why Pluto is not a planet anymore until today. Read the information below carefully and you will get the answer.
The Criteria of a Planet
Before discussing why Pluto is no longer a planet, you should understand the criteria of an object in space to be called a planet. A Planet should meet the requirements below.
- A planet should travel around the sun according to its orbit.
- A planet has sufficient mass to perform gravity to keep its core strength and its shape round.
- A planet can clear the neighborhood around its orbit.
The Reasons Why Pluto is No Longer Planet in Our Solar System
1. Pluto is a Dwarf Planet
One of the reasons why the International Astronomical Union or IAU says that Pluto is not a planet is because it is a dwarf planet. So, what is the difference between a dwarf planet and a planet? A planet can clear other objects around its orbit.
On the other hand, a dwarf planet can’t do it. It means that Pluto becomes dominant without other bodies of comparable size other than its satellites. The orbit is also not stable as a planet. Indeed, a planet should have a stable orbit.
2. The Size
IAU defines the size of an object in space to be called a planet. For example, the diameter of the inner planets, such as Mercury, Venus, Earth, and Mars is less than 13.000 kilometers. The diameter of the outer planets, such as Jupiter, Saturn, Uranus, and Neptune is over 48.000 kilometers.
So, how about Pluto? The diameter of this dwarf planet is only 2.390 kilometers. The size is too small to be called a planet. Pluto is even smaller than the moon.
3. The Gravitation
Just like the size, a planet also has standard gravitation. The gravitation of most planets in our solar system have at least 3.7. On the other hand, the gravitation of this dwarf planet is only 0.58. The bigger the mass of a planet, the bigger the gravitation compared to stars and the black hole.
Because of that, Pluto doesn’t have a criterion of a planet just like the eight planets. So, you can also explain that the gravitation is too small to be called a planet if your teacher asks what is the reason why Pluto is not a planet.
4. The Distance
Previously, Pluto was known as the farthest planet from the sun. Nowadays, its distance becomes one of the reasons why Pluto is no longer a planet. NASA estimates that the distance between Pluto and the sun is approximately 6 billion kilometers. Its distance affects the characteristics of this object.
5. The Way Pluto Travel Around the Sun
All planets in the solar system travel around the sun in a perfect circle according to their orbit. Pluto is not following this rule. Instead of traveling around the sun in a circle, Pluto travels around the sun in an oval-shaped path. Since Pluto doesn’t meet this criterion, experts say that Pluto can’t be classified as a planet.
6. The Forming
Pluto was formed from a small rocky core. This rocky core binds other materials, including water ice, methane, carbon monoxide, and nitrogen ice. Indeed, it is different compared to other planets. A planet is often formed from gas and dust particles. The particles stick together and travel around the sun according to their orbit.
7. Pluto Doesn’t Have a Magnetic Field
Pluto doesn’t have a magnetic field like Jupiter, Saturn, Uranus, and Neptune. Those planets even have a stronger magnetic field compared to the earth. One of the reasons why Pluto doesn’t have a magnetic field is because of its small size and slow rotation. Indeed, Mars and Venus don’t have a magnetic field like Pluto, but the size and rotation of these two objects meet the criteria to be called a planet.
8. Pluto Has a Larger Moon Than Its Size
Unlike other planets, Pluto has a larger moon than its size. This dwarf planet has five moons, which are Charon, Styx, Nix, Kerberos, and Hydra. Charon is the closest to Pluto. Interestingly, the size is also larger than Pluto. Astronomers discovered that the size of this moon is half the size of Pluto.
What Does Pluto Like?
Now, you finally know that Pluto is only a dwarf planet and not a planet. This explanation may make you want to know what Pluto looks like. Based on the New Horizon spacecraft, Pluto consists of a variety of surface features. One of them is mountainous surfaces as high as 11.000 feet or 3.500 meters.
The height of this surface is similar to the Rocky Mountains on Earth. The surface of this dwarf planet is also covered by methane and nitrogen ice. Based on the materials, scientists predict that the mountains on the surface are made of water ice. The spacecraft also captured a large heart-shaped region. The left side of the region consists of carbon monoxide ice.
Can You Live in Pluto?
Another big question is whether humans can live in Pluto or not. You probably can’t live on this dwarf planet. Imagine that you are about to visit the coldest places in the solar system. The temperature reaches -375 degrees Fahrenheit up to -400 degrees Fahrenheit. It is the same from -226 degrees Celsius to -240 degrees Celsius.
It means you are about to stay in an area with a lot of ice. Plus, the gravity is too weak in Pluto. As a result, it will be difficult to stand on the ground. You will fly around the surface. There is not enough oxygen on this dwarf planet. That’s why it is impossible to live in Pluto.
The Location of Pluto in Space
You may be curious about where is Pluto even though it is no longer a planet. Pluto still orbits the sun about 3.6 billion miles or 5.8 billion kilometers away. It is located in a region known as Kuiper Belt. Pluto travels around the sun in a very slow rotation. Because of that, a day in Pluto is 153 hours whereas you only have 24 hours a day on Earth. A year on Pluto is up to 248 earth years. This explanation may tell where is Pluto now.
Now, you know what are the reasons why Pluto is not a planet anymore. At least, you can answer the question deeper when your teachers ask about it. The most important thing is that you finally understand why there were 9 planets in the solar system in the past and there are only 8 planets left until today.
