In the solar system, Venus is the second planet in the solar system according to its distance from the sun. Its radius is slightly smaller than that of the earth, about 6073 kilometers, its volume is only 0.88 times that of the earth, its mass is 0.8 times that of the earth, and its average density is slightly smaller than that of the earth. And its brightness is second only to the moon in the night sky.
Venus is surrounded by dense atmosphere and clouds. The clouds are at the top of the atmosphere, with a thickness of about 20 ~ 30 kilometers. It is composed of concentrated sulfuric acid droplets, which are also doped with sulfur particles, so its sky looks orange. The atmosphere is located below the clouds, and its main components are about 96% carbon dioxide and a small amount of nitrogen.
The surface temperature of Venus is as high as 485℃, the lowest temperature is 465℃, and the average temperature is 475℃. It can be seen from this data that the surface of Venus is very hot and the temperature difference is very small, only 20℃. This is mainly due to the greenhouse effect. The greenhouse effect refers to the heat insulation effect caused by the lack of heat exchange with the outside world in a closed space that transmits sunlight. Carbon dioxide and thick clouds only allow sunlight to pass through, but do not allow heat to radiate into space through clouds. So the enclosed space absorbs heat continuously, making the surface of Venus hotter and hotter. At the same time, atmospheric movement realizes atmospheric convection and makes the internal heat transfer uniform, so its temperature difference between day and night is not large.
The dense atmosphere also causes the pressure on Venus to be very high, about 90 times that of the earth, which is equivalent to the pressure in the 900-meter deep sea of the earth. In this harsh environment, the surface of Venus is hazy and the sky is orange. There is no water on its surface and in the atmosphere, but it often rains a lot of corrosive acid rain, accompanied by lightning for a long time.
Scientists have theoretically calculated that the internal structure of Venus is similar to that of the Earth. The inner core is composed of iron and nickel, the middle mantle is mainly composed of silicon, oxygen, iron, magnesium and other compounds, and the outer thin shell is mainly composed of silicon compounds.
The surface of Venus is 70% plain, 20% highland and 10% lowland. Because of the strong atmospheric protection, meteoroids will be torn before reaching the surface of Venus, so there are only a few craters on Venus. Instead, there are a large number of volcanoes, the largest number in the solar system. Volcanoes on Venus do not erupt violently as on earth, but flow out lava, which may be related to its special structure. There are more than 150 large shield volcanoes on Venus. Most of these shields are between 100km ~ 600km in diameter and about 300 ~ 5000 m in height.
The period of Venus' revolution around the sun, also called sidereal day, is 224.7 Earth days, and its solar day is 1 16.75 Earth days. Solar day refers to the number of days when the sun is observed once on Venus. Venus' rotation period is 243 earth days, but its direction is opposite to that of most planets in the solar system, and it turns from east to west, so there will be a strange phenomenon on Venus, that is, the sun rises in the west and sets in the east. At the same time, because every day is very long, there will be an experience of spending years on Venus.