Saturn was called "town star" or "complement star" in ancient times, because Saturn's period of revolution was about 29.5 years, and China had 28 lodges in ancient times. Saturn stays in a constellation almost every year, which means to suppress or fill the constellation, so it is called "town star" or "star filling", with a diameter of 1 19300 km (9.5 times that of the earth), making it the second largest planet in the solar system. It is very similar to its neighbor Jupiter. Its surface is also a sea of liquid hydrogen and helium, and it is also covered with thick clouds. The wind on Saturn is raging, and the wind speed in the east-west direction can exceed 1600 km per hour. The clouds over Saturn are caused by these strong winds, and they contain a lot of crystalline ammonia.

Saturn: The radius is 60,268km, and the mass is 5.69 *10.26kg..

Saturn (Saturn)

The orbit is 654.38+0.4294 million kilometers away from the sun and 654.38+0.0759.5 days away from the period of revolution, which is equivalent to 29.5 Earth years with an apparent magnitude of 0.67. Among the planets in the solar system, Saturn's halo is the most striking, which makes Saturn look like wearing a beautiful straw hat. Observations show that the substances that make up the halo are crushed ice, rocks, dust, particles and so on. They are arranged in a series of circles and revolve around Saturn.

Saturn moves slowly, so people regard it as a symbol of mastering time and destiny. In Roman mythology, it was called the second generation God Cronus, who ascended the throne of God after overthrowing his father. No matter in the east or the west, Saturn is closely related to human agriculture, and the symbols expressed in astronomy are like a scythe that dominates agriculture.

Before 178 1 discovered Uranus, people thought Saturn was the farthest planet from the sun. Saturn can be seen in the telescope, which is surrounded by a beautiful ring of light. Saturn has more moons. Up to 1978 and 10 have been discovered and confirmed, and new discoveries have been made one after another.

Saturn is like Jupiter in many ways. For example, it is a giant planet with a volume of 745 times that of the Earth and a mass of 95. 18 times that of the Earth. Among the eight planets in the solar system, Saturn is second only to Jupiter in size and mass. Like Jupiter, it is surrounded by colorful clouds and guarded by more satellites. It is oblate because it rotates very fast. The equatorial radius is about 60,000 kilometers. The average density of Saturn is only 0.70g/cm ~ 3, which is the lowest among the eight planets. If you put it in water, it will float on the water. Saturn's large radius and low density make its surface gravity acceleration close to that of the earth. Saturn's brightness when it hits the sun can be compared with that of the brightest star in the sky. Because the plane of the halo does not coincide with Saturn's orbital plane, and the direction of the halo plane is unchanged when it runs around the sun, the apparent area of the halo is not fixed from the earth, so the apparent brightness of Saturn also changes. When the visible area of Saturn's rings is the largest, Saturn appears brighter; When the line of sight coincides with the plane of the halo, the halo appears as a straight line, and Saturn appears darker. The brightness difference between them is about 3 times.

Saturn's orbit around the sun has a radius of about 65.438+0.4 billion kilometers, and its orbit is oval. Its distance from the sun is about1.500 million kilometers at perihelion and apohelion. The average speed of Saturn's revolution around the sun is about 9.64 kilometers per second, and its period of revolution is about 29.5 years. Saturn also has four seasons, but each season lasts for more than seven years, because it is far from the sun, and it is extremely cold even in summer. Saturn's rotation speed is very fast, but the rotation speed at different latitudes is different, which is greater than Jupiter's. The rotation period on the equator is 18 hours 14 minutes, which becomes 10 hour and 40 minutes at 60 degrees latitude. That is to say, on Saturn's equator, there are only 10 hours and 14 minutes in a day and night.

Saturn's atmosphere is mainly composed of hydrogen and helium, and contains methane and other gases. Clouds of dense ammonia crystals float in the atmosphere. From a telescope, these clouds form parallel stripes like Jupiter's clouds, but they are not as bright as the Wood Nebula, but they are much more regular than the Wood Nebula. Saturn's cloud belt is mainly golden yellow, and the rest are orange and light yellow. Saturn's surface is as unstable as Jupiter's. The airflow near its equator is consistent with its rotation direction, and the speed can reach 500 meters per second, which is much larger than the wind on Jupiter.

Saturn is green near the polar regions, which is the darkest area on the whole surface. According to infrared observation, cloud top temperature is-170℃, which is 50℃ lower than Jupiter. Saturn's surface temperature is about-140℃. White spots sometimes appear on Saturn's surface. The most famous white spot was found in August 1933. This white spot appears in the equatorial region, which is egg-shaped and reaches 1/5 of Saturn's diameter. After that, the white spot continued to expand and almost spread to the entire equatorial belt.

Due to the low surface temperature and high escape speed (35.6 km/s), Saturn retained all the hydrogen and helium when it was formed billions of years ago. Therefore, scientists believe that studying the current composition of Saturn is equivalent to studying the original composition of the early solar system, which is very helpful for understanding the internal activities and evolution of the sun. It is generally believed that Saturn's chemical composition is similar to Jupiter's, but its hydrogen content is less. Saturn has more methane than Jupiter, but less ammonia.

1In April, 1973, pioneer of interplanetary probe 1 1 launched by the United States discovered that Saturn has an extensive ionosphere composed of ionized hydrogen, and its upper temperature is about 977℃. Observations show that there are auroras in Saturn's polar regions.

At present, it is believed that when Saturn was formed, it was initially the accretion of soil and ice, followed by the accumulation of gas. So Saturn has a core with a diameter of 20,000 kilometers. This core accounts for 10% to 20% of Saturn's mass. The core is surrounded by an ice shell with a thickness of 5,000 kilometers and a metal hydrogen layer with a thickness of 8,000 kilometers. In addition to metallic hydrogen, there is an extensive molecular hydrogen layer.

1969, an airplane made an infrared observation of Saturn's thermal radiation in the upper atmosphere of the earth, and found that Saturn, like Jupiter, radiated twice as much energy as it received from the sun. This shows that Saturn and Jupiter have the same internal energy. Later, the infrared detection of Pioneer 1 1 confirmed this point, and it was measured that the energy emitted by Saturn was 2.5 times that absorbed from the sun.