Mercury data fast ttttt

Mercury is the closest planet to the sun among the eight planets in the solar system, about 0.39 astronomical units away from the sun, and it is an asteroid full of potholes. After Pluto was downgraded to a dwarf planet, it became the smallest of the eight planets. In ancient times, people noticed the existence of mercury, which often appeared near the horizon shortly after sunset in the morning or evening. So in ancient China, Mercury was also called the morning star (appearing in the morning) or the evening star (appearing after dusk). Mercury has a radius of about 2440 kilometers, which is the smallest of the eight planets. How small is it? Mercury is even smaller than Jupiter's largest moon Ganymede and Saturn's largest moon Titan! ! A clear edge of Mercury can be seen in the photo, indicating that there is no thick atmosphere on the surface of Mercury. Mercury's surface condition is similar to that of the moon, with many rugged craters, but without the structure of the "sea" on the moon, large cliffs are also common. In addition to these structures, Mercury has other relatively flat plains, which may be ancient volcanic areas. The picture on the left shows the contrast between the photos of the surface of mercury and the surface of the moon. The topography on the surface of Mercury shows that Mercury was hit by many meteorites after its formation, resulting in such a pitted and scarred appearance. The largest crater on Mercury is the Caroli Basin, with a diameter of about 1300 km, which is a quarter of the diameter of Mercury. According to the calculation, it should be a relic that was once hit by an asteroid with a diameter of 100 km. A feature of Mercury's surface is the cliff terrain with height difference of several kilometers everywhere. This terrain is called "wrinkled ridge", and the longest one stretches for 500 kilometers. This kind of terrain can only be seen on mercury. The reason why Discovery Rupes caused this terrain may be the folds caused by the rapid contraction of Mercury shortly after its formation. It is estimated that Mercury contracted by about 5% from its initial formation to cooling, seriously distorting the earth's surface. The picture on the left shows that Northwest University first discovered the wrinkled terrain on the surface of Mercury. In the picture, it can be observed that there is a folded terrain running through the center. Through the two craters in the picture, we can imagine the process of mercury being evaporated and squeezed. In the reanalysis of the latest data, it is considered that there may be a new volcanic movement of Mercury, but further research is needed to confirm it. The temperature difference between day and night of Mercury's surface environment is very large, which is 430 degrees Celsius during the day and about-170 degrees at night. It is a very unsuitable environment for human beings to live directly, and it is also the planet with the largest temperature difference among the eight planets in the solar system. However, in recent observations, it has been found that there may be ice in some parts of the South Pole and the North Pole that will never be exposed to sunlight, making Mercury a planet with ice. The picture on the right shows the structure of the crater on the surface of Mercury photographed by Mariner 10 spacecraft, and the dark shadows may contain ice. How do astronomers detect whether there is water on Mercury? Actually, it depends on radar observation. In the radar observation of mercury, it is found that there is a strong radar reflection in the polar region of mercury. The characteristics of this reflection are somewhat similar to the ice sheet of Mars. Therefore, it is suspected that there is ice in the polar regions of Mercury, and its scale and diameter are about 100 km. In addition, Mercury is also one of several places in the solar system where human beings may migrate. There are some ring-shaped mountain structures at the poles of Mercury, because it will not be affected by sunlight all year round, and human beings have the opportunity to use the ice and artificial insulation devices there to create an artificial migration environment. Because mercury is too close to the sun, the solar radiation received by the bright area is too strong, which greatly increases the surface temperature. In the part that is not exposed to sunlight, because mercury has almost no atmosphere, heat is not easy to conduct, which makes the surface temperature of mercury in this part very low, which will form such a strong contrast. Mercury's star structure The average density of Mercury is second only to that of the Earth in the planet, reaching 5.43g/cc, which is very unusual. The average density of the earth is high because of the gravity of the earth itself, but the gravity of mercury is very small, which means that the composition of mercury is very heavy. Therefore, according to the measurement data of Mercury, astronomers speculate that Mercury may have a large iron core, and its diameter can reach 2/3 to 3/4 of that of Mercury. Mercury is like an iron ball, and the silicate composition on its surface is only a thin shell. Astronomers put forward three theories to explain why the density of mercury is so high, namely, impact theory, evaporation theory and huge impact theory. At present, the most powerful theory is the huge impact theory, that is, mercury was hit by a big impact in the early stage, the metal core in the center solidified rapidly, and the external rock material was blown away, thus producing such a result. Mercury's atmospheric structure There is almost no atmosphere on the surface of Mercury, so the surface is easily hit by interstellar matter. Mercury's atmosphere is very different from that of planets such as Earth and Venus. Due to the influence of solar wind, the frequency of replacement is very high. In fact, the gas molecules on the surface of Mercury collide with Mercury more frequently than with each other, so Mercury's atmosphere is also called the outer atmosphere. Recently, a sodium cloud was found in the outer atmosphere of Mercury. In addition, Mercury also has a magnetic field, but the intensity is very small, which is about 1% of the earth's magnetic field. Further research on the atmospheric structure and magnetic field of Mercury is expected to be revealed when the Messenger spacecraft approaches the probe at 20 1 1. The current observation results of mercury's satellites have not found that mercury has satellites. Mercury is also one of the two planets without satellites (the other is Venus).

Reference: residence.educities.edu/listeve//Space/earth-title

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Reference: zh. *** /zh-/%E6%B0%B4%E6%98%9F

Mercury is the closest planet to the sun, so it runs faster than other planets, with a speed of nearly 48 kilometers per second and orbits the sun once every 88 days. Looks like the moon. Its perihelion often changes. Mercury can usually be seen with binoculars or even the naked eye, but because it is very close to the sun, it is difficult to see in the afterglow of morning or sunset. The declination radius is 2439.7km and the rotation time is 58.6462. The revolution speed of celestial planets on the earth is 87.969 kilometers per second. The average surface temperature 179℃, the highest temperature during the day is 427℃, and the lowest temperature at night is-0/73℃. The number of satellites is 0, the average distance from the sun (10,000km) is 57.09, and the main components with an average density of 5.42 GM/cm are: 42% oxygen, 29% sodium, 22% hydrogen, 6% helium, 0.5% potassium and a small amount of argon, carbon dioxide, water and argon. Only one space exploration ship, American sailor 10, has been to Mercury. It flew over Mercury three times between 1973 and 1974, and mapped 45% of its surface area. On the other hand, the Hubble Space Telescope can't observe Mercury, because Mercury is too close to the sun, and Hubble's precision instruments will be burned by strong sunlight. Mercury is characterized by: its surface is covered with impact craters and is very old, and there is no plate movement; Mercury has only a very thin atmosphere, consisting of atoms blown from its surface by the solar wind. Because mercury is very hot, these atoms will soon escape into space, so compared with the stable atmosphere of Venus and the earth, the atmosphere of mercury is constantly reborn. There are some huge cliffs on the surface of Mercury, the longest of which can reach hundreds of kilometers and the highest drop can reach three kilometers. Some of these cliffs cut holes and other features, and it can be known that these cliffs were caused by the early surface contraction of Mercury. It is estimated that this shrinkage rate is about 0. 1%, which is equivalent to shortening the radius by 1 km. The largest terrain on the surface of Mercury is the Callaris Basin (right), with a diameter of about 1.

The 300-kilometer-wide great basin (Moon Sea), which is generally considered to be similar to the surface of the moon, should also have been caused by a super-large impact in the early solar system, and some special terrain directly behind it (left) may also have been caused by the same event. In addition to the crater area, Mercury also has some relatively flat places, some of which may be caused by early volcanic activity, but others may be filled with ejecta that hit the crater. The orbit of Mercury is very eccentric, and its perihelion is only 4.

6 million kilometers; But there are seven apohelions.

0 million kilometers, the precession of perihelion is very slow. /kloc-astronomers in the 0/9th century carefully measured the revolution data of Mercury, but it was difficult to perfectly explain Newton's laws of motion. For decades, there has been an unexplained gap between observation data and theoretical deduction. At that time, it was generally inferred that there was another undiscovered planet affecting the orbit of Mercury. This problem was later solved by Einstein's general theory of relativity. In fact, the perfect inference of mercury orbit is one of the great examples of general relativity that can be accepted by academic circles. Mercury's special revolution speed and elliptical orbit have created some wonderful effects on the surface of Mercury: at a certain longitude, the sun will rise, and then it will look bigger and bigger as it slowly rises to the zenith; At the zenith, the sun will stop, then walk backwards, then stop and go forward until the sun sets. In the process, the sun will look smaller and smaller. Between the rising and setting of the sun, other stars experienced three ups and downs! What is observed in other places is different, but it is also wonderful. Before 1962, it was generally believed that a "day" of mercury was as long as a "year", so that mercury would always face the same side of the sun as the moon does to the earth. However, after 1965 observed its rotation speed with Doppler radar, this idea was overturned: Mercury rotates three times for every two revolutions! Mercury is the only known star in the solar system that does not oscillate in the manner of 1: 1 Temperature difference The temperature difference on the surface of Mercury is the most extreme in the whole solar system: from 90K to 700 K; Although the temperature of Venus is much higher, the temperature difference is much smaller. Density The average density of Mercury (5.43gm/cm3) is much higher than that of the moon (3.34gm/cm3), which is the second highest density among the nine planets, second only to the Earth. However, the high density of the earth is caused by its great gravity compaction effect. Otherwise, the density of mercury will be higher than that of the earth, which means that the high-density iron core of mercury accounts for a larger proportion of the whole star than that of the earth, which may be the main component of mercury, so it will only have a very thin rock shell (equivalent to the crust and mantle). It is estimated that the core radius reaches 1.

800 to 1

900 kilometers, and its rock shell is only 500 to 600 kilometers thin. In addition, some iron cores may be liquid.

Reference: home vigator/~ tangchanhung/universe/9stars/mercury

Mercury is an inner planet, which only appears in the form of morning star or evening star in the morning, but it is more difficult to see than Venus, another inner planet. Seen from the earth, the brightness of Mercury varies greatly, with the apparent magnitude ranging from -2.3 to 5.7, but its maximum separation angle from the sun is only 28.3. At the brightest time, it should be easy to see from the earth technically, but it is not easy to find because it is too close to the sun in the sky. Because unless there is a solar eclipse, mercury is usually invisible in the sunlight. In the northern hemisphere, mercury can only be seen in the early morning or dusk; When the distance appears at the latitude south of the equator, Mercury can be seen in the completely dark sky in the mid-latitude of the southern hemisphere.

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