How terrible is Pluto? Being kicked out of the nine planets, in fact, is not at all unjust.

Pluto has been discovered by human beings since the 20th century, which is both remote and mysterious. And its name is named after prout's "death of the underworld" in Roman mythology, which is even more memorable. Although he was eliminated from the nine planets in the past two years, he was downgraded to a "dwarf planet". But its strangeness and mystery are still so strong in the eyes of scientists.

The origin of Pluto

Pluto is a dwarf planet in the Kuiper Belt, which is mainly composed of rocks and ice. Its weight is less than 0.24% of the earth, its gravity is only one-fifteenth of that of the earth, and its diameter is about 66% of the moon. So far, we have found that Pluto has five satellites, Phobos I to Phobos V, which are named the boatman of Styx, the goddess of the night, Hydra, the guardian of the underworld and Styx respectively.

Pluto is actually very far away from the sun. The distance from the sun is about 40 times that of the earth. You should know that the earth is 65.438+0.5 billion kilometers away from the sun. So Pluto is destined to be extremely cold. The average temperature on its surface is only about MINUS 230 degrees.

It is very cold on Pluto. Scientists compare it to the legendary "underworld" and "underworld". It is "cold and tyrannical" all the year round, and human beings can't stand it.

The surface of Pluto is covered with a lot of ice, which contains a lot of methane and frozen nitrogen. The mass of the whole planet is composed of rocks and ice water, just like a rocky planet with an ice shell, but Pluto's volume is relatively small. If compared with it, it is only 1/6 of the moon.

During the exploration in recent years, scientists found that Pluto looks very cold and there is a lot of nitrogen ice flowing inside. American probes have detected a crack surface similar to the earth on Pluto, which shows that there was geological movement inside Pluto.

The probe photographed Pluto and a "snail"

There is a huge ocean under Pluto's ice, which may have the potential to breed life. Is there life in this cold world? In 2006, scientists launched the New Horizon probe. One of the missions of this probe is to fly over Pluto to explore it. After nearly nine years' flight, the New Horizon probe flew over Pluto at close range in 20 15, sending back a lot of data and photos of Pluto, presenting an unknown scene of Pluto to our human eyes.

In one of the photos sent back by the New Horizon probe, there is an object that looks like a snail on the surface of Pluto. At that time, many enthusiasts speculated that there was a creature on the surface of Pluto. Scientists from NASA explained that this so-called "snail" picture was indeed taken on the surface of Pluto, but it was not a creature of Pluto, but a frozen cement floating on the surface of Pluto's dense solid nitrogen.

Not only that, but even more frightening is that more than 98% of Pluto's surface is solid nitrogen, with a small amount of methane and a very small amount of carbon monoxide. Because the temperature is very low, most of Pluto's substances are solid, and there are many methane icebergs.

/kloc-at the beginning of the 0/9th century, scientists were very keen on finding unknown planets in the solar system. At that time, the academic circles found that the orbit of Uranus did not conform to Newton's law of gravity, which may be caused by the existence of gravity of an unknown giant planet.

Finally, in 1846, Neptune was discovered. However, the academic circles have also found that Uranus and Neptune have abnormal orbits, and it is speculated that there should be a giant planet that has not yet been discovered, which is the so-called "ninth planet".

Half a century has passed, and the ninth planet has not been found. Until the early 20th century, Percival Lowell, a rich man in Boston, USA, was rich and liked astronomy, so he simply built an observatory-Lowell Observatory with his own money (1890). After the observatory was built, he not only used it to observe Mars, but also looked for the ninth planet. But until he died in 19 16, the ninth planet was not found.

Later, in 1926, Tang Bo was hired to join the Observatory, and his main job was to find the ninth planet. 1930 February 18, Tang Bo compared the observation images of 65438+/kloc-0 on October 23rd and 29th, and found a small bright spot. After calculation, it was confirmed that this is the legendary ninth planet, and it was made public on March 13.

In fact, it doesn't matter whether Pluto is terrible or not. Pluto was kicked out of the nine planets, not because it was terrible, but mainly because it did not conform to the latest definition of planets by astronomers!

Pluto is just a very ordinary celestial body in the solar system, and it is very special. For example, it is very far from the sun, with the nearest distance of 4.4 billion kilometers and the farthest distance of 7.4 billion kilometers. Such a long distance makes the surface temperature of Pluto very low, close to MINUS 230 degrees Celsius. Look at Pluto, the sun is almost spherical, more like a very bright point!

In 2006, more and more dwarf planets were discovered in the Kuiper Belt, such as Eris and orpheus, especially Eris, which is heavier than Pluto, so astronomers redefined several elements of the planet, and Pluto was kicked out of the ranks of nine planets because it did not meet the definition of planet!

Not because Pluto is too small, but mainly because there are other celestial bodies near Pluto's orbit. Pluto did not clean up other celestial bodies near its orbit, so it was relegated to the ranks of dwarf planets! Mercury is not too massive, but there is only one planet near its orbit, so Mercury is defined as a planet!

With the improvement of human science and technology, people know more about Pluto. In 20 15, the American new horizons spacecraft passed Pluto and made a detailed exploration of Pluto and its satellites!

In recent years, some scientists have said that there may be a ninth planet outside Pluto, which is very far from the sun, but there is no strong evidence to prove this, because the distance is too far, astronomers need more detailed long-term observation!

The weirdness of Pluto

Scientists discovered Pluto and called it the ninth planet, but finally eliminated it, mainly because it did not conform to Newton's force!

Pluto orbits the sun in a special elliptical orbit with a period of 248 earth years. The nearest and farthest distances from the sun are 29.7AU and 49.3AU (AU respectively (Au is astronomical unit, the average distance from the earth to the sun). When Pluto is closest to the sun, it is even closer to the sun than Neptune. And when it is far away, it is so far away.

The farthest distance from the sun is 7.4 billion kilometers, and it takes more than 6 hours for sunlight to reach here. On Pluto, the sun is just a bright star. So it's hard to observe on earth.

Quite simply, it doesn't fit the definition of a planet.

But interestingly, its appearance redefined the planet. It can be said that this new definition is aimed at Pluto.

Since Pluto was discovered, people began to estimate its mass.

At first, people thought that the mass of this planet was several times that of the earth. In subsequent observations, Pluto's mass declined again and again.

It was not until 1978 that Ka Rong, the natural satellite of Pluto, was observed. Thanks to it, the mass of Pluto has been accurately calculated, and the result is only one-fifth of that of the earth and much smaller than that of the moon.

However, several moons of Pluto were later discovered. At that time, people thought that only planets deserved natural satellites, so Pluto was always regarded as a planet.

In 2005, the observation data at that time showed that there was a celestial body in the Kuiper Belt that was 1.6 times larger than Pluto and had a mass of 13%, and named it Venus (in fact, with the further observation, Venus was not bigger than Pluto).

Traditionally, Venus is the 10 planet, but there are many celestial bodies larger than Venus in the Kuiper Belt.

If the planets are not redefined, there may be dozens of planets in the solar system in the near future.

Finally, in 2006, the International Astronomical Union voted to exclude Pluto.

The other eight planets in the solar system basically orbit the sun on the same plane (ecliptic plane), but unlike Pluto, Pluto's orbit deviates from the ecliptic plane 17 degrees. Pluto would not have been discovered for many years if it had not been found just near the ecliptic.

It is too far from the sun. We all know that it takes only 8 minutes for sunlight to reach the earth, but it takes 5 hours for sunlight to reach the surface of Pluto. So the surface of Pluto is very cold, from MINUS 238 degrees to 2 18 degrees. Therefore, nitrogen, carbon monoxide and methane on the surface of Pluto are frozen into solid state. Under the action of gamma rays and sunlight in deep space, the white ice layer turned pink-brown. If humans are inside, their bodies will be frozen instantly.

There is also a very huge satellite behind Pluto, which is more than half the diameter of Pluto. The two of them revolve around each other, so scientists think this is a binary star system.

The mass difference between Pluto and Ka Rong is not too big, but they are close. The two planets are locked by tidal forces and always face the same side. It's two people dancing hand in hand and spinning each other. In addition, the direction of their revolution is almost perpendicular to the other eight planets, which is completely "unruly".

After years of exploration, some special landforms of Pluto have been presented to people. For example, huge ice cracks, snakeskin-shaped ice ridges and moving frozen volcanoes can be seen everywhere on Pluto's surface. ...

Why Pluto was expelled by nine planets?

In fact, in the 1980s, scientists suspected that Pluto was not the cold edge of the solar system. Later, in 1992, the telescope in Hawaii discovered and confirmed the existence of the Kuiper Belt. Since then, academic circles have discovered 1500 Kuiper Belt objects. Some scientists estimate that there are about 65,438+10,000 celestial bodies with a diameter exceeding 100 km in the entire Kuiper Belt. Therefore, there are more and more questions about Pluto's status as the ninth planet.

Therefore, the International Astronomical Union (IAU) updated the definition of planet in 2006 and directly downgraded Pluto from a planet to a dwarf planet. There are currently five dwarf planets, namely Pluto, Venus, Venus, Venus and Ceres.

Pluto has been "downgraded", and it should be NASA that is emotionally complicated, because the "New Horizon" detector was launched that year. After flying for 9 years, I finally flew over Pluto on July 20 15 14 and took photos of Pluto. Surprisingly, there is a huge heart-shaped ice sheet on the surface of Pluto, which surprised everyone on earth.

Conclusion:

Next, the photos sent back by New Horizons made scientists stop thinking that Pluto is just a planet full of ice and rocks. Its atmospheric thickness exceeds 1600 km, and it is a dynamic world with drastic atmospheric changes, and it is changing all the time. And there may be underground water sources, which really have the potential for human immigrants to live. I don't know if there is life now. But the extremely low temperature environment, even if the gas has turned into a solid, should be the forbidden area of life.

Although Pluto seems terrible to us, it is really true that Jupiter's crisis is much higher than Pluto's. But the horror of Pluto is beyond scientists' cognition, so scientists mainly think it is mysterious. Mystery often represents the unknown. This information is one-sided, and we don't know much, so there is nothing we can do. Pluto is too far away from the earth, so it's really not easy to go there.