Which planet is the closest to Earth? It is Venus, whose closest distance from Earth is only about 40.5 million kilometers. So, which planet is most similar to Earth? Or Venus.
The similarity between Venus and Earth is reflected in two aspects, one is "appearance" and the other is "behavior". In terms of "appearance", Venus is 95% of the diameter of the Earth, while the mass is about 80% of the mass of the Earth. In terms of "behavior", Venus's orbital period is 224.7 days, which is relatively close to Earth's 365.24 days. It can be said that in the solar system, no planet can reach the level of Venus to the level of Venus, so people often refer to Venus as Earth's "sister planet". Since it is a sister planet, why doesn't humans seem to be too interested in Venus? In fact, Venus was not snubbed by humans from the beginning.
In the beginning, humans were very keen to explore Venus, and the first to detect Venus was the United States launched Mariner 2, which flew past Venus on December 14, 1962, and obtained atmospheric temperature data from Venus.
The Soviet Union followed suit, firing four Venus probes in succession, but the first three failed, and in October 1967, venus was successfully detected with Venus 4. This is just the beginning, and then entered the wave of Venus exploration that lasted for more than 20 years, and the last time humans explored Venus was in 1989, this time the United States used the space shuttle to launch the Magellan Venus probe in space, with the Magellan probe, human beings obtained the clearest image of the surface of Venus and valuable data ever, but it was also from this that humanity lost interest in Venus.
Through the detection of Venus, human beings finally discovered that the similarity between Venus and the earth is only superficial, and its internal difference from the earth is very different.
Venus has a dense atmosphere, and its atmospheric composition is very different from the Earth, its main component is carbon dioxide, so the greenhouse effect is serious, on the surface of Venus, the average temperature can reach 462 degrees Celsius, which is far beyond the limit of life can withstand, but this is not the most terrible. There are thick sulfuric acid clouds in Venus's atmosphere that are more than 20 kilometers thick, so concentrated sulfuric acid rain has become a common weather here, and no known life form can withstand such baptism. Venus's environment dooms it to not become a habitable planet, nor does it have any modification value, so it can only be left out in the cold by humans.
Venus's "appearance" and "behavior" are so similar to Earth's, why is "contained" so different from Earth's?
In fact, Venus did not look like this from the beginning, and even in the near past, Venus was likely to be a habitable planet, and it was likely to be an impact. Compared to other planets in the solar system, Venus is unique in two places, one is the direction of its rotation, and the other is its rotation speed. All the planets in the solar system rotate from west to east, except for Venus, which rotates so slowly that it takes 243 days to rotate for a week, longer than a single rotation. Why is that? The rotational dynamics of the planets are derived from the conservation of angular momentum of the primordial nebula before the formation of the solar system, so the rotation direction of the original Venus must have been from west to east.
What can change the direction of a planet's rotation is a violent impact, so we can imagine that at some point in the past, a larger object collided with Venus and changed the angular momentum of Venus, so Venus began to rotate in reverse, and the rotation was very slow.
What causes a drastic change in The environment of Venus is not the impact, nor the change in the direction of rotation, but the change in the speed of rotation. Venus has an iron core, but the magnetic field is almost non-existent, why? It is because Venus rotates too slowly, that is to say, the change in the rotation speed of Venus directly leads to the disappearance of the magnetic field. Without the protection of the magnetic field, Venus's atmosphere is gradually blown away by the solar wind.
After the atmosphere is blown away, liquid water on the surface of Venus is rapidly lost.
The ocean exists above the surface, and the disappearance of the ocean is a huge change in the surface pressure, so the earth's crustal activity intensifies, and a succession of volcanic eruptions begins, and scientists estimate that the active volcanoes on the surface of Venus can reach millions. Massive volcanic eruptions brought in large amounts of carbon dioxide and other acidic gases, and Venus acquired a new atmosphere, which was produced faster than it could be blown away by the solar wind. Although the dense atmosphere reflects most of the sunlight back, the atmosphere composed of carbon dioxide has an excellent thermal insulation effect, so the greenhouse effect on Venus is serious, and soon a high temperature of 462 degrees Celsius is born. This is how Venus went from being a habitable planet to a hellish planet.