The information of Mercury, Saturn, Venus, Jupiter, Mars, Earth, Neptune, Pluto and Uranus is about 200 words each, and it is urgent to choose! ! !

Among the nine planets, Mercury, Venus, Earth and Mars are collectively called Earth-like planets. Their similarity is that they are mainly composed of stone and iron, with smaller radius and mass, but higher density. Jupiter, Saturn, Uranus and Neptune are called woody planets. Their similarity is that they are mainly composed of hydrogen, helium, ice, methane, ammonia and so on. , while stone and iron account for only a small proportion. Their mass and radius are much larger than that of the earth, but their density is lower. Pluto is a special planet. The distance from the planet to the sun is regular, that is, the distance from the planet to the sun (denoted by a) is a=0.4+0.3×2n (astronomical unit), where n is-∞, 0, 1, 2, 3, 4, 5, 6, 7 from Mercury to Pluto in turn. Note that 7 corresponds to Pluto, not Neptune, and Neptune has no n correspondence, which destroys the empirical formula of planetary distance. The rotation periods of the Earth, Mars, Jupiter, Saturn, Uranus and Neptune are about 12 hour to one day, but the rotation periods of Mercury, Venus and Pluto are very long, which are 58.65 days, 243 days and 6.387 days respectively. Most planets have the same direction of rotation and revolution, but Venus is the opposite. Except Mercury and Venus, all other planets have satellites orbiting them, forming a satellite system. In the solar system, more than 1600 comets have been found, most of which revolve around the sun in the same direction, but some of them rotate in the opposite direction. Comets will have strange shape changes when they orbit the sun. There are also a large number of meteoroids, large and small, in the solar system, some of which are in groups and are the products of the disintegration of comets. Large meteoroids fall to the ground and become meteorites. The solar system is a small part of the Milky Way. It's just one of hundreds of billions of stars with galactic coefficient. It is about 8,500 parsec from the center of the Milky Way, which is less than 30,000 light years. The sun takes the whole solar system around the center of the Milky Way. Visible, the solar system is not in the center of the universe, nor in the center of the Milky Way. The sun was formed by the collapse of a small piece of interstellar cloud 5 billion years ago, and its life span is about 65.438+0 billion years.

mercury

Mercury is the closest planet to the sun, and its angular distance from the sun never exceeds 28. In ancient China, Mercury was called a star. In ancient times, Westerners thought that Mercury was two planets. When they see it at dusk, they call it mercury, and when they see it at dawn, they call it Apollo. Later, people knew that Mercury and Apollo were the same star, so they called Mercury Mercury. Mercury was a messenger in Roman mythology who sent messages to the gods. He wears a hat with wings, flying shoes and a wand, and walks like a fly. He is omnipotent and unpredictable. Mercury, like mercury, is really changing and elusive. In another month and a half, it will run from the easternmost end of the sun to the westernmost end, with an average speed of 47.89 kilometers per second, making it the fastest moving planet in the solar system.

One day equals two years.

transit of mercury

When mercury walks between the sun and the earth, we will see a small black dot passing through the circle of the sun. This phenomenon is called the transit of mercury. The reason is similar to the solar eclipse, except that Mercury is farther away from the earth than the moon, and its apparent diameter is only one tenth of that of the sun 1.9 million. The area blocked by mercury is too small to weaken the brightness of the sun, so the transit of mercury is invisible to the naked eye and can only be observed through telescope projection. Mercury transits occur every 100 years 13 times on average. The next transit is at 5: 42 on June 6th 1999 1 16. Friends with binoculars should not miss the opportunity.

Venus

Venus was called Taibai or Taibai Venus in ancient China. It is sometimes the morning star, which appears in the eastern sky before dawn and is called "Qi Ming". Sometimes it is a dim star, which appears in the western sky after dusk and is called Chang Gung. Venus is the brightest star in the whole day except the sun and the moon, just like a dazzling diamond, so the ancient Greeks called it Aphrodite, the goddess of love and beauty, while the Romans called it Venus, the god of beauty. In astronomy, the symbol of Venus is the precious mirror used by the beauty god when dressing.

Venus, like the moon, has a round and round change, and once supported Heliocentrism of Copernicus. Venus is very similar to the earth: the radius is 6050 kilometers, only slightly smaller than the earth; The average density is about 95% of the earth; The mass is 865438+ 0.5% of the earth; In addition, Venus is surrounded by atmosphere and clouds. Like Mercury, it is the only two big planets in the solar system without natural satellites. Venus's orbit is very close to a perfect circle and coincides with the ecliptic plane. Its period of revolution is about 224.7 days, but its rotation period is 243 days. That is to say, Venus's "one day" is longer than its "one year". Venus is the only big planet in the solar system that rotates in the opposite direction. Venus's atmosphere is thick and strange, and its main component is carbon dioxide, accounting for more than 97%. Therefore, the "greenhouse effect" on Venus is extremely strong. Venus's atmospheric density is 100 times that of the earth, and its atmospheric activity is intense, and lightning and thunderstorms often appear in the atmosphere. Venus has almost no magnetic field. Its terrain is relatively flat, but the landform is complex. Theoretically, its internal structure should be similar to that of the earth, but it needs to be confirmed by observation. Venus has a transit phenomenon and a "Venus eclipse" phenomenon, both of which are once in a hundred years.

earth

The earth is one of the nine planets in the solar system, ranking third in the order from near to far from the sun. It has a natural satellite-the moon, forming a celestial system-the earth-moon system.

The earth rotates from west to east and revolves around the sun at the same time. The combination of the earth's rotation and revolution has produced the alternation of day and night and the change of seasons on the earth. The speed at which the earth rotates is uneven. At the same time, due to the gravity of the sun, the moon and the planets, as well as the various functions of the atmosphere, the ocean and the materials inside the earth, the direction of the earth's rotation axis will change in space and the earth itself. The inertial centrifugal force produced by the earth's rotation makes the spherical earth gradually expand from the poles to the equator, becoming a slightly flat ellipsoid of revolution at present, and the polar radius is about 2 1 km shorter than the equatorial radius.

The earth can be regarded as a series of concentric layers. The earth has a core, a mantle and a shell structure. There are hydrosphere, atmosphere and magnetosphere outside the earth, forming a sheath around the solid earth.

As a planet, the earth originated from the primitive solar nebula 4.6 billion years ago.

launch

From near to far from the sun, Mars is the fourth planet. To the naked eye, it is a striking bright lux star. It travels slowly among the stars. When looking at Mars from the earth, it sometimes goes straight and sometimes goes backwards. The darkest apparent magnitude of Mars is about+1.5, etc. And at the brightest time, it is brighter than the brightest star Sirius, reaching -2.9. This is because the Earth and Mars are in their respective orbits, and the distance between them is always changing. Mars is as bright as fire, its brightness is constantly changing and its position is uncertain, which is confusing. So China called Mars "sparkling" in ancient times. In western ancient Roman mythology, it was imagined as Mars, the god of war in armor and covered in blood, that is, Ares in Greek mythology. Ares had a noble life. His father is Zeus, the king of the gods, and his mother is Hera, the queen of heaven. Astronomically, the symbol of Mars is the combination of the spear and shield of Mars.

Mars has many characteristics similar to that of the earth. It is 227.94 million kilometers away from the sun, about 1.5 times the distance between the sun and the earth. The angle between the rotation axis and the orbital plane is 24, which changes all the year round like the earth. It is less than half the rotation of the earth, that is, 24 hours, 37 minutes and 22.6 seconds. So the length of day and night of Mars and Earth is basically the same, but the period of revolution around the sun is almost equal to two years for Mars. Because Mars is far from the sun, its period of revolution is 687 days. Mars is about half the diameter of the earth; 1/6 smaller than the earth; The mass is only110 of the earth; The atmosphere of Mars is much thinner than that of the earth. Its main components are carbon dioxide, accounting for 95%, nitrogen accounting for 3%, and a very small amount of oxygen and water.

The average temperature of Mars is minus 23 degrees Celsius. Due to the thin and dry atmosphere of Mars, the temperature difference between day and night is very large, which is much larger than that on the earth. Due to the low surface temperature and low air pressure on Mars, carbon dioxide and water in the atmosphere are almost saturated. As long as the temperature drops slightly, carbon dioxide and water vapor will condense. There is little water in the atmosphere of Mars. Scientists estimate that if all the water ice on Mars melts into water, only an ocean with a depth of 10 meter can be formed on the surface of Mars. Compared with the vast ocean on the surface of our earth, the water on Mars is negligible.

Jupiter

Jupiter is the most striking planet in the solar system. It is the oldest and the largest of the nine brothers. Its brightness is second only to Venus. In ancient China, it was called the "year-old star", which was used to date the years because it was known that its period of revolution was close to 12. The west calls Jupiter "Jupiter", the main god in Roman mythology. Equivalent to the king Zeus in Greek mythology.

The diameter of Jupiter is about 143000 km, which is 1 1.25 times the diameter of the earth, 13 16 times the volume of the earth and 2.5 times the mass of all other planets. The average density of Jupiter is quite low, only 1.33 g/cm3. The period of revolution of its orbit around the sun is about 12 years, and its rotation takes only about 10 hour. Because it rotates too fast, the star flattens, and its equatorial radius differs from the polar radius by as much as 5000 kilometers. Jupiter has no solid shell. It is a liquid planet composed of liquid hydrogen.

Jupiter's interior is a solid core composed of iron and silicon, called Jupiter's core, and the temperature is as high as 30000℃. The outer part of Jupiter's core is mostly hydrogen, and the molecular layer of liquid hydrogen is laminated with liquid metal, which is called Jupiter's mantle. Outside Jupiter's mantle is Jupiter's atmosphere with a thickness of 1000 km. It is almost entirely composed of hydrogen and helium, with only a small amount of methane, ammonia and water vapor. Methane in Jupiter's atmosphere can absorb ultraviolet rays. There are also very strong and frequent lightning phenomena in Jupiter's atmosphere, with an average of about 250 times a year. Jupiter has a dense atmosphere with a series of alternating light and dark clouds parallel to the equator. The bright ones are called bands and the dark ones are called stripes. One of the most striking is the Great Red Spot in Jupiter's southern tropics, which is egg-shaped, 20,000 kilometers long and 1 1 1,000 kilometers wide.

The magnetic field intensity on the surface of Jupiter is about 10 times that of the earth, and the direction is just opposite to the earth. Jupiter has the aurora phenomenon, which is the second celestial body besides the earth to discover the aurora phenomenon.

1 On March 4, 979, when the space probe navigator1flew near Jupiter, it was found that Jupiter had a ring similar to Saturn, which was 6500 kilometers wide and 30 kilometers thick, and was composed of many black stones. Jupiter is the largest planet in the solar system with the largest number of satellites except Uranus and Saturn. Up to now, 65,438+06 satellites have been discovered, and the four brightest satellites were identified by Galileo for the first time with a telescope, so they are called Galileo satellites. In fact, as early as the Spring and Autumn Period, China's Gander and Shi Shen had already discovered one of them, calling it Alliance.

Jupiter has outstanding characteristics among planets: large mass and large volume. Its mass is two and a half times that of the other eight planets in the solar system combined, which is equivalent to 13 16 times that of the earth. If you put the earth and Jupiter together, it will be as different as the proportion of sesame and watermelon.

Although Jupiter is huge, its rotation speed is the fastest in the solar system. The rotation period is 9 hours, 50 minutes and 30 seconds. Such a rapid rotation period causes an extremely complex pattern on Jupiter's surface, which makes the air flow parallel to the equator, resulting in a huge centrifugal force. The poles are relatively flat, the equator is raised, and a cloud belt parallel to the equator appears. Jupiter's cloud belt can be divided into several layers. The color and temperature of cloud bands are different, and there are differences between bright bands and dark bands. Clouds in bright areas are composed of brightly colored ammonia ice, which is called bands; Clouds in dark areas are made of ammoniated substances, which are called stripes. Ammonium compounds come in various colors: white, orange and brown, but most of them are reddish brown.

Saturn

Saturn is a beautiful planet, the sixth farthest from the sun. Anyone who has seen Saturn through a telescope will be surprised. Saturn's orbital radius is 65.438+0.4 billion kilometers, and its maximum brightness is 0.4 magnitude when it hits the sun. On Saturn's orange surface, there are bright and dark clouds floating, and the soft and shiny halo on the equatorial plane looks like a girl wearing a sun hat from a distance.

Saturn rotates once 10 hour 14 minute. Due to the rapid rotation, the equator bulges into a oblate sphere, and the equatorial radius is more than 6000 kilometers larger than the radius of the poles. Saturn's period of revolution is 29.5 years, which is about 28 nights. It stays in the town for one night every year, so it was also called "Town Star" in ancient China. Saturn has always been regarded as the boundary of the solar system, and it was not until Uranus was discovered in 178 1 that the solar system began to expand. Saturn moves slowly, so people regard it as a symbol of time and fate. In Roman mythology, he was called the Saturnalia, that is, Cronus in Greek mythology. He is the father of Zeus, the king of the gods, who overthrew his father and ascended the throne of the gods. Both the East and the West associate Saturn with agriculture. Symbols in astronomy are like scythes that dominate agriculture.

Saturn is second only to Jupiter in size, and they have many similarities. Its diameter is about 6.5438+0.2 million kilometers, 9.5 times that of the earth; The volume is 730 times that of the earth. But its average density is even smaller than that of water, only 0.7 g/cm3. If Saturn is put into water, it will float on the water.

Saturn's internal structure is similar to Jupiter's, and it also has a core made of rocks. Outside the core is a 5000-kilometer-thick ice shell and metallic hydrogen. Outside, like Jupiter, it is surrounded by colorful clouds. These colored clouds are mainly composed of hydrogen, helium and methane. If Jupiter's atmospheric motion is changeable, then Saturn's atmospheric motion appears calm, simple and fast. The fastest jet on Saturn's surface can be as high as 400 meters per second. But Saturn's real surface is invisible. What we see is Genting, whose temperature is below -200℃.

The Voyager probe found that Saturn also has a great red spot, which is 8,000 kilometers long and 6,000 kilometers wide, much smaller than Jupiter's. It may be caused by the disturbance and rotation caused by the updraft in Saturn's atmosphere falling into the clouds again.

Uranus

It is not difficult to watch Uranus on a clear night. Its magnitude is 5.7. Its period of revolution is quite long. It orbits the sun once every 84 years, moving only 46 inches a day on average. It is not easy to distinguish it from a star. In history, it has been mistaken for many times that stars are loaded into star maps.

Uranus ranks seventh in the solar system, about 2.9 billion kilometers away from the sun. Its size is very large, 65 times that of the earth, second only to Jupiter and Saturn, ranking third in the solar system; Its diameter is over 50,000 kilometers, four times that of the earth, and its mass is about 14.5 times that of the earth.

In ancient Greek mythology, Uranus was regarded as the first god who ruled the whole universe-Uranus. He combined with Gaia, the mother of the earth, and gave birth to the later God. He tried his best to make the chaotic universe harmonious and orderly. He has a prominent position, and the Chinese translation is Uranus.

Neptune

According to the average distance from the sun, Neptune ranks eighth. Its brightness is 7.85 and so on, which can only be seen in a telescope. Because it is a light blue planet, it is named Neptune according to the traditional planetary nomenclature. Neptune is the sea god who rules the ocean in Roman mythology. He is in charge of the universe of13, which is quite amazing. Neptune's astronomical symbol symbolizes the cold shiny fork in Neptune's hand.

Pluto

Among the nine planets of Pluto, Pluto is the farthest from the sun and has the smallest mass. It hobbles in the cold and dark space 5.9 billion kilometers away from the sun, which is very similar to proto, the god of the underworld in Roman mythology. So people call it Pluto, which is the first two letters of the English name of Pluto in astronomy, and the abbreviation of the name of Lovel, an American astronomer who promoted the discovery of Pluto.

Pluto is the latest planet to be discovered. Compared with the discovery of Uranus and Neptune, the discovery of Pluto is "a lot of trouble". Pluto's brightness is very weak, only 15 and so on. Even in the photos taken by large telescopes, it is no different from ordinary stars. Finding it among thousands of stars is like looking for a needle in a haystack.

In the process of searching for Pluto, Lovel, an American astronomer who is an astronomy enthusiast, calculated the position of this unknown planet in detail and searched it carefully with a telescope, which took more than ten years. Until19161.0616 suddenly died.

1925, Lovel's brother donated a large-field photographic telescope with a diameter of 32.5 cm, which provided excellent conditions for continuing the search for new planets. From 65438 to 0929, the director of Lovel Observatory invited clyde william tombaugh to join the search for unknown planets. They searched one by one, photographed a large number of negatives, and examined each one carefully. This job is hard and boring. 193065438+1October 2 1 day, Tang Bo finally found this new planet in the negative of Gemini.

Basic data of Pluto

Mass: 0.0024 Earth mass

Radius:1350km

Period: 90465 days

Half-length diameter of orbit: 39.87 astronomical units.