Chapter Two: Planetary Members of the Solar System
The planetary members of our solar system currently mainly include: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and other eight planets, and the early Pluto has been downgraded to a series of dwarf planets. As for whether there are still objects in neptune's outer orbit that meet the definition of a planet, it has not yet been discovered.
We divide these planetary members into three categories, the first is terrestrial planets (rocky planets), which are mainly composed of silicate rocks, which are Mercury, Venus, Earth, and Mars. The second is Jupiter-like planets (gas giant planets), which are mainly made up of gases composed of hydrogen and helium, which are Jupiter and Saturn, respectively. The third is the ice giant, which is mainly composed of icy solids composed of water, ammonia and methane, and is Uranus and Neptune, respectively.
Let's introduce these 8 planets by distance from the sun
The first section is terrestrial planets
Terrestrial planets are mainly solid planets composed of rocks and silicates, which are Mercury, Venus, Earth, and Mars, respectively. It is called a terrestrial because the other planets are similar to Earth and are rocky solid planets.
2.1.1 Mercury
See the article "Mercury of Astronomical Knowledge - A Simple Article"
2.1.2 Venus
Venus is the second closest planet to the Sun, with an orbit between Earth and Mercury. It is the brightest planet in the night sky and the brightest object in the night sky except for the Moon (except for special circumstances, such as supernovae and artificial satellites).
Fig. 2.1.2 True color image of Venus taken by Mariner 10, its surface is obscured by a thick sulfuric acid cloud
2.1.2.1 Is there really gold on Venus?
The answer is no, there is no gold on Venus. The main components of The atmosphere of Venus are carbon dioxide and nitrogen, as well as other small amounts of elements. In rocky bodies, the crust of Venus is composed mainly of silicate minerals, and the core may be composed of semi-solids dominated by iron and nickel.
2.1.2.2 Origin of the name Venus
The name venus is Chinese term derived from ancient times, as does Mercury. Before the Han Dynasty, it was called Taibai, Star or Dahu, and it was called Qiming in the east in the morning and Chang Gung in the west at night. Until the Western Han Dynasty, when the astronomer Sima Qian observed Venus, he found that the color of Venus was white and yellow, so it was associated with the "Five Elements" theory at that time and officially named Venus.
In Western Roman mythology, the origin of the name Venus is Venus, the goddess of love and beauty in Roman mythology. It is also the "goddess" of the night sky, because it is bright and easy to see.
2.1.2.3 How big is Venus?
Venus is about the same size as The Earth, and the other sizes are similar to the Earth, so it is often referred to as Earth's sister star. The average size of Venus is about 6051.8 km, and the Earth is about 6371 km.
Figure 2.1.2.3 Comparison of the size of Venus (the surface of radar imagery) with the size of the Earth.
2.1.2.4 How far away is Venus from the Sun? How far is it from Earth?
The average distance between Venus and the Sun is about 108 million kilometers, almost twice as far away from Mercury. Because Venus has a much smaller eccentricity than Mercury, its orbit is approximately circular. Venus, like Mars, is a close neighbor of Earth, about 50 million kilometers from Earth.
Figure 2.1.2.4 The animation simulates the rotation of Venus and the Earth
2.1.2.5 Rotation and rotation of Venus
Looking down from the North Pole of the Earth, you can see that all the planets are orbiting the Sun in a counterclockwise direction. And most planets rotate counterclockwise, but Venus does the opposite in terms of rotation. But Venus is not the only planet we currently know of in the solar system that rotates clockwise, and the other planet that rotates clockwise is Uranus. Venus' rotation is the slowest known of the planets in the Solar System , taking about 243.025 days to rotate. Because its rotation is so slow, it is extremely close to a spherical shape. If you watch the sunrise and sunset on Venus, then its day is very long, and it will be a scene of rising in the west and setting in the east. (PS: We often say that the sun has come out of the west" about the impossible, which is obviously possible, provided that you should say observation from Earth.) ）
Venus orbits the Sun in the same direction as earth, in a counterclockwise direction. It takes about 224.701 days for Venus to orbit around, compared to about 365.256 days on Earth. Since this number of days is not very different from the rotation period, staying on Venus for one day is like staying on Venus for 1 year. (PS: This is similar to "living like a year").
2.1.2.6 Characteristics of Venus
Venus is similar to Earth, with a solid surface and an atmosphere. Some of the surface of Venus is similar to That of Earth, such as volcanoes, impact craters, plains, etc., but the other features of its surface are very different. Simply put, the environment on the surface of Venus is much harsher than earth's. For example, the atmospheric pressure is about 92 times the pressure on the Earth's surface, and it is impossible to survive even if it is not flattened.
The most striking and alluring feature of Venus is its thick atmosphere. The mass of Venus's atmosphere is about 93 times that of the Earth's atmosphere, and its main components are carbon dioxide (CO2) and nitrogen, of which carbon dioxide is the largest, accounting for about 96.5%. The thickness of Venus's atmosphere is about 250 km, and the thickness of the Earth's atmosphere is greater than 1000 km. There is also a layer above the bottom layer of Venus (the troposphere) where there is a lot of sulfuric acid, and the sulfuric acid rain formed in these places falls to 25 kilometers above the ground and is evaporated by high temperatures to form a flag-like cloud, so the sulfuric acid rain of Venus will never reach the surface of Venus. Because of the opaque cloud formed by sulfuric acid, we cannot see the surface of Venus, and we can only use radar imaging to understand the surface of Venus, although there have been Gold probes that have landed on the surface of Venus to take some pictures.
Figure 2.1.2.6 Global radar image of Magellan from 1990 to 1994 (without clouds)
Venus' thick atmosphere is caused by the runaway greenhouse effect, and studies speculate that Venus had liquid water similar to our current Earth about 4 billion years ago. However, due to the subsequent runaway greenhouse effect, the evaporation of water and the rise of other greenhouse gas levels may be the fate of the earth in the next hundreds of millions of years.
Venus's powerful greenhouse effect has resulted in temperatures as high as 464 degrees, higher than Mercury ( 452 degrees ) closer to the Sun , making it the hottest planet in the solar system.
Unlike Earth, Venus does not have a strong magnetic field generated by its core, which is produced by the interaction of charged particles of the solar wind with particles in The Venusian atmosphere.
2.1.2.7 Is it habitable on Venus?
The environment on the surface of Venus is so harsh, not only the temperature is high, but also the pressure is high, so it is almost impossible to immigrate.
Interestingly, however, temperatures at about 52.5 to 54 km above the surface of Venus range between 20 and 37 degrees, while the air pressure at an altitude of 49.5 km is equal to the atmospheric pressure at Earth's sea level. These conditions mean that humans can survive here, but this is near the sulfuric acid clouds, so we also need to consider the impact of sulfuric acid on us.
Figure 2.1.2.7 Changes in the structure, temperature, pressure and altitude of The atmosphere of Venus
2.1.2.8 How to see Venus on Earth
From our Earth' point of view, Venus is the brightest star in the night sky (here the artificial satellites at night and the Moon and supernova explosions need to be removed). Its brightest visual magnitude can reach a brightness level of about -4.9, can be seen even during the day in good air places, and can also shine like the moon at night (when there is no other light source).
In ancient times, people called Venus the Day Star or Chang Gung Star. Daystar means that bright Venus can be seen in the eastern night sky before sunrise in the morning, and Chang Gung star is a bright Venus seen in the western night sky after sunset in the evening.
Therefore, Venus can be seen in the morning or evening when it is near a large distance, that is, when it is far away from the perspective of the Sun's eye. When Venus travels farther east of the Sun, venus can be seen after sunset in the evening. When running to the west of the Sun, Venus can be seen in the morning before sunrise.
Figure 2.1.2.8a Schematic diagram of the large distance of Venus
Figure 2.1.2.8b Schematic diagram of the position of Venus seen in the morning and evening
A small archive about Venus
Mass approx: 4867500000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
Volume approx: 928430000000 cubic kilometers = 928.43 billion cubic kilometers = 92843 x 10 7 power cubic kilometers (0.857 times the Earth);
The diameter is about: 12103.6 km (0.950 times the Earth);
The rotation period is about: 5832.6 hours = 243.025 days (about 8 months);
The orbital period is about: 224.701 days (orbiting the center of the Sun, about 7 months);
The surface pressure is about: 91 standard atmospheres;
The average surface temperature is about: 464 degrees Celsius;
Distance from the center of the Sun is about: 108 million km;
The distance from the center of the Earth is about: 41.44 million kilometers;
The maximum visual magnitude seen from Earth is approximately -4.9
2.1.3 Earth
See Next: The Earth of Astronomical Knowledge - A Simple Article
Resources
1. WJ Encyclopedia
2. All data parameters are referenced to NASA-Planetary Fact Sheets
Article Author: Zero Degree Galaxy (Astronomy Online)
Auditor: Small draw
Final Review: Zero Degree Galaxy (Astronomy Online)
Editing time: July 02, 2018 - July 6, 2018
Audit time: July 8, 2018 - July 16, 2018
Last updated: Wednesday, September 12, 2018
Note: All information data is huge, it is inevitable that errors will occur, please also point out the errors so that they can be corrected.
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