Mars is one of the eight planets, ranking fourth in the sun from near to far. To the naked eye, Mars is a striking lux star, moving slowly among the stars. On the earth, it moves forward and backward, and its brightness often changes. At the darkest time, the apparent magnitude is+1.5, and at the brightest time it is much brighter than Sirius, reaching -2.9. Because Mars is as bright as fire, its brightness changes frequently and its position is not fixed, so China called Mars "sparkling" in ancient times. In ancient Roman mythology, Mars was compared to the myth of Mars, the god of war, dressed in armor and covered in blood. In Greek mythology, Mars is also regarded as the god of war. Sometimes Mars is also called "Red Planet".
Mass 6.421e+23kg.
The equatorial radius is 3397.2 kilometers.
The average density is 3.94 g/cm3.
The daily average distance is 227,940,000 km.
The rotation period is 24.6229 hours.
Period of revolution 686.98 days.
The equatorial surface gravity is 3.72 m/s 2.
The equatorial escape velocity is 5.02 km/s.
Minimum surface temperature-140℃
Average surface temperature -63℃
The maximum surface temperature is 20℃
Atmospheric pressure 0.007 bar
Atmospheric composition: carbon dioxide 95.32%, nitrogen 2.7%, argon 1.5%, oxygen 0. 13%, carbon monoxide 0.07%, water 0.0009 1% and others 0.0000.
The soil on the surface of Mars contains a lot of iron oxide. Due to long-term exposure to ultraviolet rays, iron will form a layer of red and yellow oxides. To exaggerate, Mars is like a world full of rust. Because Mars is far away from the sun, the solar radiation energy it receives is only 43% of that of the earth, so the average temperature on the ground is about 30 degrees Celsius lower than that of the earth, and the temperature difference between day and night can reach hundreds of degrees Celsius. Near the equator of Mars, the highest temperature can reach about 20℃. Mars also has an atmosphere. Its main component is carbon dioxide, accounting for about 95%, and a very small amount of carbon monoxide and water vapor.
Mars is smaller than the Earth, with an equatorial radius of 3,395km, which is half of the Earth's, its volume is less than 1/6 of the Earth's, and its mass is only110 of the Earth's. Like the earth, Mars has the structure of core, mantle and crust.
The rotation of Mars is very similar to that of the Earth, with a rotation of 24 hours, 37 minutes and 22.6 seconds. A day and night on Mars is slightly longer than a day and night on Earth. Mars makes a revolution of about 687 days, and a year of Mars is about two years for the Earth.
Mars has two satellites. One near Mars is called Phobos, and the other farther away is called Phobos. Because Mars is regarded as the god of war in Greek mythology, astronomers named its two moons after his two sons Phobos and Driss.
Phobos
Phobos
Phobos is potato-shaped, circling Mars three times a day, with an average distance of about 9378 kilometers from Mars.
It is the larger of the two satellites of Mars, and it is also the one closer to Mars. The distance between Phobos and Mars is also the shortest among all satellites and their main stars in the solar system, only 6,000 kilometers away from the surface of Mars. It is also one of the smallest satellites in the solar system.
In Greek mythology, Phobos was the son of Ares (Mars) and Aphrodite (Venus). "Phobos" means "fear" in Greek (a word-forming component of "phobia"-fear).
Phobos was discovered by Hall in 1877, first photographed by Mariner 9 in 197 1 and observed by Viking 1 and Phobos in 1977.
deimos
Deimos
Phobos is a smaller satellite far from Mars and the smallest satellite in the solar system.
Orbit: 23,459 kilometers from Mars.
Satellite diameter:12.6km (15x12.2x11).
Mass: 1.8E 15kg.
In Greek mythology, Phobos is another son of Ares (Mars) and Aphrodite (Venus). "deimos" means "panic" in Greek. Phobos was discovered by Hall in August 1877, and its photo was first taken by Viking 1 in August/977. Phobos and Phobos are composed of carbon-rich rocks like C-type asteroids, and both of them have deep pits. Phobos and Phobos may be orbiting Mars because of the disturbance of asteroids and the action of Jupiter.
There are obvious seasonal changes on Mars, which is its main similarity with the Earth. But beyond that, Mars is very different from the Earth. The surface of Mars is a desolate world, and carbon dioxide in the air accounts for 95%. The dense carbon dioxide atmosphere causes the high temperature on Venus, but on Mars, the situation is just the opposite. The atmosphere of Mars is very thin, and its density is less than 1% of the earth's atmosphere, so it is impossible to store heat. This causes the surface temperature of Mars to be extremely low, rarely exceeding 0℃. The lowest temperature at night can reach-123℃.
This is a global photo of Mars taken by NASA's Viking orbiter. You can clearly see the huge "Sailor Valley" in the picture. Sailor Valley is about 4000 kilometers long and 8 kilometers deep. (United States Geological Survey)
Mars is called the red planet, because its surface is covered with oxides, so it appears rust red. The surface of Mars is mostly desert, with a lot of red oxides, ochre gravels and solidified lava flows. There are often violent winds on Mars, which can raise dust and form a super-large sandstorm that can cover the whole planet of Mars. Every sandstorm lasts for weeks.
Both the ice sheets at the poles of Mars and the atmosphere of Mars contain water. The detection data obtained from the surface of Mars prove that in ancient times, Mars once had liquid water, and the amount of water was particularly large. These waters converge into large lakes and even oceans on the surface of Mars. Now we can see that there are many criss-crossing river beds on the surface of Mars, which may have been washed away by water at that time. In addition, many water-drop-shaped "islands" on the surface of Mars are also suggesting this to us.
Because Mars is similar to Earth, it has always been considered that there is the possibility of extraterrestrial life. Recent scientific research shows that there is no proof of life on Mars. On the contrary, there are more and more signs that Mars is more like a barren and dead world. Nevertheless, some evidence still points out that there may have been life on Mars. For example, the analysis of a meteorite from Mars found in Antarctica shows that there are some tubular structures similar to bacterial fossils in this stone. All these continue to interest people in the existence of life on Mars.
1976, Viking 1 and Viking-2 Mars probes successfully landed on Mars for the first time, returning tens of thousands of photos. That flight found no evidence of life on Mars. However, Schoultze Macuch, an American geologist, published a paper saying that the probe might have really discovered Martian creatures at that time, but people didn't realize their existence at all, because the form of Martian creatures was so different from the earth's ecology. Human probes pour water into Martian soil, which may drown Martian life in another cell. In addition, the human probe also heated Saturn's soil, which may have roasted the Martian microorganisms to death.
Mars canal
This canal is an artificial river. If we admit that there are canals on Mars, it is tantamount to admitting that there is intelligent life on Mars, which is undoubtedly a question that arouses people's interest.
Italian astronomer Schia Parelli first pointed out that there are canals on Mars. 1877, he took advantage of the encounter between the perihelion of Mars and the earth to observe Mars with a telescope with a diameter of 24 cm, and found some fuzzy straight lines on the circular surface of Mars, which connected the dark spots. After continuous observation, he found that some dark lines were as long as 120 km, criss-crossing and forming a network covering the Martian continent. It is also found that the existing two dark lines are parallel to each other and have seasonal changes. He also charted his findings and made them public. At first, Parelli guessed that these hidden lines were just waterways connecting the bay, but he didn't say that they were artificially dug. Canal, but in the 1980s of 19, his discovery attracted people's attention. Some people describe these hidden lines as rivers dug by intelligent creatures. This person is Lovel of the United States.
Lovel was fascinated by the discovery of Skia Parelli. In order to observe Mars, he built an observatory in Arizona at his own expense. After years of observation, it not only confirmed schiaparelli's discovery, but also discovered hundreds of new rivers, saying that the surface of Mars is as fine as a spider's web. He also wrote his observations into three books: Mars, Mars and its Canal, and Mars-the Residence of Life. He believes that because the air on the surface of Mars is very thin, resulting in water shortage, the Martian polar cap composed of ice and snow begins to melt in summer and become a water source. The purpose of the waterway on Mars is to lead the water from the polar cap to the arid tropical areas and irrigate the fields there. Judging from these waterways, they all converge to the center of the mainland, which is obviously purposeful. Its black spot is an oasis.
Lovel's theory aroused people's great interest and quickly swept the world. However, Lovel's theory is not one-sided, and it is constantly challenged. For example, Bayod of the United States thinks that the dark lines on Mars are not straight, irregular and unconnected at all. Anthony Adi of Greece supports Barnard's view through his own observation, and thinks that describing the dark line on Mars as a canal is purely an illusion of the eyes, "belonging to people with too rich imagination."
Because of the appearance of the above viewpoint, the myth about Martians gradually declined, and the American Mariner 9 probe further proved that the existence of the Mars Canal was false. However, Mariner 9 made an unexpected discovery, that is, there are many geological structures similar to river beds on Mars, and their positions are quite different from those described by Lovel.
Some people divide the riverbed on Mars into three categories: flowing riverbed, outflow riverbed and erosion riverbed, which are very similar to the riverbed on Earth. They split up. About a long time ago, there was a warm climate on Mars, with atmosphere and precipitation on it, which ensured the existence of rivers. Later Viking 1 (1976) not only confirmed the existence of canals on Mars, but also confirmed the existence of artificial buildings.
Shuishou valley
The largest canyon in the solar system has cut a wide hole on the surface of Mars. The majestic canyon named Mariner Canyon stretches for more than 3,000 kilometers from front to back, with the widest point reaching more than 600 kilometers, and it is about 8 kilometers down. In contrast, the Grand Canyon in Arizona is about 800 kilometers long, 30 kilometers wide and 1.8 kilometers deep. Although there is a main hypothesis that when the planet cooled billions of years ago, a crack later evolved into the present canyon, the real cause of Mariner Canyon is still uncertain. Recently, we have determined several geological evolution processes in this canyon.
References:
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launch
Mars is one of the eight planets, ranking fourth in the sun from near to far. To the naked eye, Mars is a striking lux star, moving slowly among the stars. On the earth, it moves forward and backward, and its brightness often changes. At the darkest time, the apparent magnitude is+1.5, and at the brightest time it is much brighter than Sirius, reaching -2.9. Because Mars is as bright as fire, its brightness changes frequently and its position is not fixed, so China called Mars "sparkling" in ancient times. In ancient Roman mythology, Mars was compared to the myth of Mars, the god of war, dressed in armor and covered in blood. In Greek mythology, Mars is also regarded as the god of war. Sometimes Mars is also called "Red Planet".