Since 1930, we have been accustomed to the sun having nine planets, but in 2006, the International Astronomical Society kicked Pluto out of the planetary family.
Pluto was demoted to a dwarf planet.
Then why is Pluto downgraded?
Because astronomers believe that there are 3 conditions for becoming a planet.
1. It has enough mass to become a ball by relying on its own gravity.
2. There will be no nuclear fusion reaction inside.
3. It can clear celestial bodies near orbit and become the largest celestial body in its orbit.
, and Pluto does not meet the third item.
Because in 2003, astronomers discovered that there was Zina outside Pluto (it was once considered the tenth largest planet in the solar system), and Zina was larger than Pluto, which also became one of the reasons why Pluto was downgraded.
Now talk about the strange solar system planets .
Poor Mercury: Heaven is too far, the sun is too close
Mercury is the closest planet to the sun, which also leads to it being most affected by the gravity of the sun's father.
If you are a little far away from the sun, Mercury will not be the smallest of the eight planets. How small is
?
The mass of Mercury is only 5.53% of that of Earth.
In addition, Mercury is also the planet with the largest temperature difference. During the day, Mercury's temperature is as high as 427℃, and at night it can be cold to -173 degrees Celsius.
"Earth of the Solar System" Venus: Do you want to live like a year? Come to me,
. The size and mass of Venus are only one circle smaller than that of the Earth, and there is not much difference (the mass of Venus is 81.5% of that of the Earth).
But Venus is really a weird thing!
It is the only planet in the solar system with the opposite rotation direction and the opposite rotation direction .
This also takes 224 days for Venus a year (the Earth timed) and a day on Venus takes 243 days.
On Venus, you can live like a year!
But this is not the most bizarre one. There are more than 100,000 volcanoes on Venus, and 97% of the atmosphere is carbon dioxide.
In addition, there is a 30 kilometers thick cloud of concentrated sulfuric acid outside in Venus atmosphere.
If you live on Venus, you need to live a life of life like years and enjoy the joy of hypoxia. If you want to escape from Venus, you also need to pass through the clouds of concentrated sulfuric acid.
Therefore, astronomers nickname Venus "the hell of the solar system."
Mars: The sadness of being small? Or is it another reason
Mars and Earth have many similarities, which is also the reason why many science fiction movies use Mars as a theme.
However, although it is far from the sun, Mars is still underdeveloped.
The mass of Mars is only 11% of that of the Earth, which makes Mars' gravity not as large as that of the Earth.
At the same time, this also makes Mars' atmosphere density only 1% of that of the Earth.
The thin atmosphere on the surface of Mars also prevents Mars from keeping heat, and the average surface temperature of Mars is only -63℃.
But there is evidence that Mars once had rivers and oceans, and meteorites from Mars also indicate that there was life.
But now Mars is completely dead silent!
gaseous Jupiter : the fattest but very weak
Jupiter's volume is 1316 times larger than the earth, but its mass is only 318 times heavier than the earth.
There is a category of planets in the solar system. They call small size but large average density and slow rotation speed. The few satellites in are called " type of earth planets "
such as Mercury, Venus, Earth and Mars.
, and the size of large size, small average density, fast rotation speed and many satellites is called " type of wood planet "
, such as Jupiter, Saturn , Uranus , Neptune .
Jupiter is the most representative Jupiter. Its surface is 80% hydrogen. Since Jupiter's temperature is only -148℃, it is a sea of liquid hydrogen.
In addition, Jupiter also has an large red spot , which is really big and can be stuffed into several earths (the one like the eyes in the picture below is Jupiter's large red spot, which can be stuffed into several earths).
Astronomers also discovered that there is a thermonuclear reaction inside Jupiter, and they believe that Jupiter is developing towards star .
Saturn: the most beautiful planet, I am the one who is
Saturn is not as big as Jupiter, but it is similar to Jupiter's structure and is a liquid planet.
But Saturn is most famous for her beautiful Saturn rings !
It made 7 Saturn rings with small moons and ice through gravity! (Three main rings, two dark rings, and two were not discovered until 1979)
Uranus: a lying planet, the work of changing day and night is not done
Uranus, as a woody planet, is mainly composed of rocks and ice.
In addition, Uranus has 20 halos!
but not bright, so it cannot compete with Saturn for beauty.
is ordinary.
However, Uranus has a unique skill in the entire planet - lying down.
Generally speaking, planets are slightly tilted, such as the Earth, which vividly reflects this phenomenon.
You can treat planets as walking people. When ordinary planets turn around the sun, their bodies are tilted, but they are basically standing upright around the sun.
But if Uranus is compared to humans, it is just lying around the sun.
This also causes only a small number of Uranus to change day and night, while other places often have day or night for decades.
Neptune: The ordinary edge younger brother
Neptune is also gas planet . Although it is inconspicuous,
, one of its cores is as heavy as the earth.
Although it is inconspicuous,
also makes 5 halos.
Try to learn from Saturn and Uranus.
