Chapter 1661: Uranus

Chapter 1851 Uranus
At this time, Zhao Zhongyao looked at Feifei and said, ‘The eighth amethyst gem we are looking for is on Tianweisan. As long as we drive the spacecraft and fly directly to Tianwei San, we can find the eighth amethyst gem. ’
Feifei heard what his father said, and said, ‘Okay, let’s go to Tianwei San! ’
Tiantian and Qu Yuqian have no opinion either. As long as Zhao Zhongyao and Feifei decide things, they will not express any different opinions.
In this way, after Zhao Zhongyao discussed with Feifei, he flew to Tianwei San again with his spacecraft.
When flying to Sky Guardian, Feifei asked Zhao Zhongyao to tell him some astronomical knowledge about Sky Guardian.
‘Dad, since we are going to Celeste now, can you tell us some knowledge about Celeste, so that we can learn more about this satellite of Uranus. Feifei looked at Zhao Zhongyao and said.
After hearing what Feifei said, Zhao Zhongyao said, ‘To understand Tianweisan, you must first understand its home planet, Uranus. Let me tell you about Uranus first! ’
After hearing what my father said, Feifei said again, ‘Okay, then you can tell us about Uranus first! ’
‘Ok, let me tell you about Uranus first. Said Zhao Zhongyao.
Next, Zhao Zhongyao told Feifei some knowledge about Uranus.
Uranus, one of the eight planets in the solar system, is the seventh planet in the solar system from the inside out (18.37~20.08 astronomical units). Its volume ranks third in the solar system (larger than Neptune) and fourth in mass (smaller than Neptune). Almost lying horizontally orbiting the sun. The cover image is a photo taken during the most recent flight by Voyager 2 to Uranus.
Uranus is the first planet discovered using a telescope. William Herschel discovered the planet in his courtyard on March 13, 1781. The internal and atmospheric composition of Uranus and Neptune are different from the larger gas giants (Jupiter, Saturn), and astronomers have established the classification of ice giants to define them. Uranus has 27 known natural satellites, of which 5 are larger in size, and there are 13 weaker planetary rings.
The main components of Uranus’ atmosphere are hydrogen, helium, methane and deuterium. It is speculated that it may be rich in heavy elements inside. The mantle is composed of methane and ammonia ice and may contain water. The inner core is composed of ice and rocks. Uranus is the coldest planet in the atmosphere of the solar system, with a minimum temperature of 49K (-224°C)
Uranus is mainly composed of rocks and water ice materials with different compositions. The main element of Uranus is hydrogen (83%), followed by helium (15%). In many respects, Uranus (and Neptune) is different from Jupiter and Saturn, which are mostly composed of gaseous hydrogen. Its properties are closer to the core parts of Jupiter and Saturn, and there is no giant liquid gas surface surrounded by Jupiter-like planets.
The mass of Uranus is approximately 14.5 times that of Earth, which is the smallest among the Jupiter-like planets. Its density is 1.29 grams cm³ only slightly higher than Saturn. Although its diameter is similar to Neptune (about 4 times that of Earth), its mass is lower. These values ​​show that Uranus is mainly composed of various volatile substances such as water, ammonia and methane. The total content of ice inside Uranus cannot be accurately known. It varies according to the model selected, but it is always between 9.3 and 13.5 times the mass of the earth. Hydrogen and helium account for only a small part of the whole, about 0.5 to 1.5 earth mass. The remaining mass (0.5 to 3.7 earth mass) is the rock material.
The standard model structure of Uranus includes three levels: in the center is a rocky core, in the middle is an ice mantle, and the outermost is a shell composed of hydrogen and helium. In comparison, the core is very small, with only 0.55 Earth mass and a radius of less than 20% of Uranus; the mantle is a behemoth with a mass about 13.4 times that of the Earth; and the outermost atmosphere is relatively unclear, about The expansion occupies the remaining 20% ​​of the radius, but the mass is only about 0.5 times that of the earth.
The density of the core of Uranus is about 9gcm³, the pressure at the junction of the core and the mantle is 8 million bar and the temperature is about 5000K. The ice mantle is not actually composed of so-called ice in the general sense, but a hot and dense fluid composed of water, ammonia and other volatile substances. These fluids are highly conductive and are sometimes referred to as a water-ammonia ocean. The large structures of Uranus and Neptune are quite different from those of Jupiter and Saturn. The composition of ice is more than that of gas, so it is reasonable to separate them into another category of ice giants.
The models considered above are more or less standard, but other models can also meet the observed results. For example, if a large amount of hydrogen and rocks are mixed in the mantle, the total amount of ice will be reduced, and the total amount of rocks and hydrogen will increase; the available data are not enough to allow us to confirm which model Is correct.
The fluid structure inside Uranus means that there is no solid surface and the gas atmosphere is gradually transformed into an inner liquid layer. However, in order to facilitate the rotation of the oblate sphere, when the atmospheric pressure reaches 1 bar and is defined and considered as the surface of the planet, the equatorial radius and polar radius of Uranus are 25559±4 and 24973±20 kilometers, respectively. Such a surface will serve as the zero point of height in this article.
Uranus has 27 known natural satellites. These satellites are named after the characters in the operas of William Shakespeare and Alexander Pope. The names of the five main satellites are Tianwei, Tianwei, Tianwei, Tianwei and Tianwei. Celeste and Celeste were the first and second Uranus satellites discovered by William Herschel on March 13, 1787. Celeste and Celeste were discovered by William Russell in 1851. of.
But it was not until 1852 that William Herschel’s son John Herschel named the four satellites. In 1948, Gerald Kuiper discovered the fifth satellite, Tianwei. The mass of the Uranus satellite system is the least among gas giants, and the total mass of the five main satellites is less than half the mass of Triton.
The largest satellite, Titan, has a radius of only 788.9 kilometers, less than half of the moon, but slightly larger than Saturn's second largest moon, Titan. The albedo of these satellites is also relatively low, approximately 0.2 for Oba and 0.35 for Oba. These satellites are composed of ice and rock, about 50% ice and 50% rock. Ice may contain ammonia and carbon dioxide.
Zhao Zhongyao looked at Feifei and told him some knowledge about Uranus. After Feifei listened, he had a general understanding of this gas giant planet in the solar system.
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