The information on Mercury, Saturn, Venus, Jupiter, Mars, Earth, Neptune, Pluto, and Uranus is about 200 words each. It needs to be carefully selected. Urgent! ! !
Among the nine planets, Mercury, Venus, Earth and Mars are generally called terrestrial planets. Their common feature is that they are mainly composed of stone and iron, with small radius and mass. , but the density is higher. Jupiter, Saturn, Uranus and Neptune are called Jupiter-like planets. Their unique characteristic is that they are mainly composed of hydrogen, helium, ice, methane, ammonia, etc., with only a very small proportion of stone and iron. Its mass and radius are much larger than those of Earth, but its density is lower. Pluto is a special planet. The distance of planets from the sun has regularity, that is, calculated from closest to far from the sun, the distance from the planet to the sun (expressed by a) a = 0.4 0.3 × 2n (astronomical units) where n is -∞ from Mercury to Pluto. ,0,1,2,3,4,5,6,7. Note that 7 corresponds to Pluto and not Neptune. Neptune does not have an N corresponding to it, which destroys the empirical formula for planetary distances. The rotation periods of the Earth, Mars, Jupiter, Saturn, Uranus, and Neptune are about 12 hours to one day, but the rotation periods of Mercury, Venus, and Pluto are very long, 58.65 days, 243 days, and 6.387 days respectively. The rotation directions and revolutions of most planets The direction is the same, but Venus is in the opposite direction. Except for Mercury and Venus, other planets have satellites orbiting them, forming satellite systems. In the solar system, more than 1,600 comets have been discovered. Most comets orbit the sun in the same direction, but some orbit in the opposite direction. Comets exhibit strange shape changes as they orbit the sun. There are also a large number of large and small meteoroids in the solar system. Some meteoroids are in groups. These meteoroid groups are the products of the disintegration of comets. Large meteoroids fall to the ground and become meteorites. The solar system is an extremely small part of the Milky Way. It is just one of the hundreds of billions of stars in the Milky Way. It is about 8.5 kiloparsecs, or less than 30,000 light-years, from the center of the Milky Way. The sun carries the entire solar system around the center of the Milky Way. It can be seen that the solar system is not at the center of the universe, nor is it at the center of the Milky Way. The sun was formed by the collapse of a small cloud after the disintegration of interstellar clouds 5 billion years ago. Its lifespan is about 10 billion years.
Mercury
Mercury is the planet closest to the sun. Its angular distance from the sun never exceeds 28°. In ancient China, Mercury was called the star. In ancient times, Westerners thought Mercury was two planets. When they saw it in the twilight, they called it Mercury, and when they saw it in the morning light, they called it Apollo. Later, people learned that Mercury and Apollo were the same star, so they called Mercury Mercury. Mercury is the messenger in Roman mythology who delivers messages to the gods. He wears a hat with wings on his head, wears flying shoes, holds a magic wand, and walks as fast as flying. His powers are vast and elusive. Mercury is indeed like Mercury, moving quickly and elusively. In one and a half months, it will run along a peculiar curve from the easternmost point of the sun to the westernmost point, with an average speed of 47.89 kilometers per second, which is The fastest moving planet in the solar system.
One day equals two years
Mercury transit
When Mercury goes between the sun and the earth, we will see a small circle on the sun's disk. The black spot passes through, a phenomenon called a transit of Mercury. The principle is similar to that of a solar eclipse, except that Mercury is farther from the earth than the moon, and its apparent diameter is only 1.9 million times that of the sun. The area that Mercury blocks the sun is too small to weaken the sun's brightness. Therefore, Mercury's transit cannot be seen with the naked eye and can only be observed through projection through a telescope. Transits of Mercury occur an average of 13 times every 100 years. The next transit will be at 5:42 on November 16, 1999. Friends with telescopes should not miss this opportunity.
Venus
Venus was called Taibai or Taibai Venus in ancient China. Sometimes it is a morning star, appearing in the eastern sky before dawn, and is called "Qiming"; sometimes it is an evening star, appearing in the western sky after dusk, and is called "Chang Geng".
Venus is the brightest star in the sky besides the sun and the moon. It is like a dazzling diamond, so the ancient Greeks called it Aphrodite, the goddess of love and beauty, and the Romans called it For Venus (Venus)---the goddess of beauty. The astronomical symbol of Venus is the mirror used by the goddess of beauty when dressing up.
Venus has waxing and waning phases like the moon, which supported Copernicus’ heliocentric theory. 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 81.5 of the Earth; in addition, Venus also has an atmosphere and clouds around it. Like Mercury, it is the only two large planets in the solar system without natural satellites. The orbit of Venus is very close to a perfect circle and closely coincides with the ecliptic plane. Its revolution period is about 224.7 days, but its rotation period is 243 days. In other words, Venus's "day" is longer than its "year". Venus is the only large planet in the solar system that rotates in the opposite direction. The atmosphere of Venus is thick, dense and peculiar. Its main component is carbon dioxide, accounting for more than 97%. As a result, the "greenhouse effect" on Venus is extremely strong. The density of Venus's atmosphere is 100 times that of Earth's, and its atmosphere is highly active, with frequent lightning and thunderstorms in the atmosphere. Venus has essentially no magnetic field. Its terrain is relatively flat, but the landform is complex. Its internal structure can be theoretically deduced to be similar to that of the Earth, but it has yet to be confirmed by observation. Venus has transit phenomena and "Venus eclipses" phenomena, both of which are rare in hundreds of years.
Earth
The Earth is one of the nine planets in the solar system. It is the third planet in order from closest to the sun. It has a natural satellite - the moon, and the two form a celestial body 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 produces the alternation of day and night and the changes of the four seasons on the earth. The speed of the Earth's rotation is uneven. At the same time, due to the gravitational effects of the sun, moon, and planets, as well as the various effects of the atmosphere, oceans, and internal materials of the earth, the direction of the earth's rotation axis changes in space and within the earth itself. The inertial centrifugal force generated by the Earth's rotation causes the spherical Earth to gradually expand from the poles toward the equator, becoming the current slightly flattened ellipsoid, with the polar radius approximately 21 kilometers shorter than the equatorial radius.
The Earth can be viewed as consisting of a series of concentric layers. The interior of the Earth has core, mantle, and shell structures. The Earth's exterior contains the hydrosphere and atmosphere, as well as the magnetosphere, which forms the mantle surrounding the solid Earth.
As a planet, the Earth originated from the primitive solar nebula 4.6 billion years ago.
Mars
Mars is the fourth planet in order from nearest to far from the sun. To the naked eye, it is a striking fiery red star. It travels slowly among the stars. When viewed from the Earth, Mars sometimes moves forward and sometimes retrograde. The dimmest visual magnitude of Mars is about +1.5, and at its brightest, it is brighter than the brightest star Sirius, reaching -2.9. This is because the Earth and Mars are running in their own orbits, and the total distance between them is is constantly changing. Mars is as bright as fire, its brightness is constantly changing, and its position is uncertain, which is confusing. Therefore, Mars was called "Yinghuo" in ancient China. In the mythology of ancient Western Rome, it is imagined as the god of war "Mars" wearing armor and covered in blood, which is the god of war Ares in Greek mythology. Ares was born into a noble family. His father was the god-king Zeus and his mother was the queen Hera. The symbol for Mars in astronomy is the spear and shield of Mars combined.
Mars has many features similar to 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 its rotation axis and the orbital plane is 24°, and it has the same changes in the four seasons of the year as the earth; its rotation takes more than half an hour longer than the earth, which is 24 Hours, 37 minutes and 22.6 seconds. Therefore, the length of day and night on Mars and Earth are basically the same, but the period of orbiting the sun is that one year on Mars is almost equal to two years on Earth. Because Mars is far from the sun, it takes 687 days to complete one revolution.
The diameter of Mars is about half that of the Earth; its volume is less than 1/6 that of the Earth; its mass is only 1/10 that of the Earth; its atmosphere is far thinner than that of the Earth, and its main components are carbon dioxide, accounting for 95%, and nitrogen accounting for 3 %, and a very small amount of oxygen and water.
The average temperature on Mars is -23°C. Because the atmosphere of Mars is thin and dry, the temperature difference between day and night is very large, which is much greater than the temperature difference between day and night on Earth. Due to the low temperature and low pressure on the surface of Mars, carbon dioxide and water in the atmosphere are generally saturated. As long as the temperature drops slightly, carbon dioxide and water vapor will condense. There is very little water in the atmosphere of Mars. Scientists estimate that if all the water ice on Mars were melted into water, it would only form a 10-meter-deep sea on the surface of Mars. The amount of water on Mars pales in comparison to the vast oceans on our planet.
Jupiter
Jupiter is the most eye-catching planet in the solar system. It is the eldest among the nine planetary brothers---the largest. Its brightness is second only to Venus. In ancient China, it was called the "Sui Star" and was used to mark the year because it was known that its revolution period was nearly 12 years. The West calls Jupiter "Jupiter", the main god in Roman mythology. Equivalent to the king in Greek mythology---the god Zeus.
Jupiter has a diameter of approximately 143,000 kilometers, which is 11.25 times the diameter of the Earth, its volume is 1,316 times that of the Earth, and its mass is 2.5 times that of all other planets. Jupiter's average density is quite low, only 1.33 g/cm3. It takes about 12 years to orbit the sun once, and only takes nearly 10 hours to rotate once. Because it spins too fast, the star becomes flat, and its equatorial radius differs from its polar radius by as much as 5,000 kilometers. Jupiter has no solid outer shell; it is a liquid planet composed of liquid hydrogen.
The interior of Jupiter is a solid core composed of iron and silicon, called the Jupiter core, with a temperature as high as 30,000°C. Most of the outside of Jupiter's core is hydrogen, and the layer of liquid hydrogen molecules and liquid metal is called the Jupiter mantle. Outside the Jupiter mantle is Jupiter's atmosphere, which is 1,000 kilometers thick and is almost entirely composed of hydrogen and helium, with only trace amounts of methane, ammonia and water vapor. Methane in Jupiter's atmosphere absorbs ultraviolet light. There are also very strong and frequent lightning phenomena in Jupiter's atmosphere, with an average of about 250 times per year. Jupiter has a dense atmosphere with a series of alternating light and dark cloud belts parallel to the equator. The bright ones are called bands and the dark ones are called streaks. The most eye-catching one is the Great Red Spot located in the southern tropical zone of Jupiter. It is egg-shaped, 20,000 kilometers long and 11,000 kilometers wide.
The magnetic field strength on the surface of Jupiter is about 10 times that of the Earth, and its direction is exactly opposite to that of the Earth. Jupiter has auroras, and it is the second celestial body after the Earth to have auroras discovered.
When the "Voyager 1" space probe flew near Jupiter on March 4, 1979, it discovered that Jupiter has a ring like Saturn. It is 6,500 kilometers wide and 30 kilometers thick. It is made up of many rings. Made of black stones. Jupiter is the planet with the most satellites in the solar system except Uranus and Saturn. So far, 16 have been discovered. The 4 brightest ones were identified by Galileo for the first time with a telescope, so they are called Galilean satellites. In fact, as early as the Spring and Autumn Period, my country's Gan De and Shi Shen had discovered one of them and called it an alliance.
Jupiter has outstanding characteristics among the 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 1,316 times that of the Earth. If you put the Earth and Jupiter together, they are as different as sesame seeds and watermelons.
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 has created extremely complex patterns on the surface of Jupiter, prompting the air flow to be parallel to the equator, generating huge centrifugal force. The poles are relatively flat, the equator is bulging, and cloud belts parallel to the equator appear. Jupiter's cloud belts can be divided into several layers. The cloud belts have different colors and temperatures, and are divided into light and dark bands. The clouds in the bright area are composed of ammonia ice and are brightly colored, called bands; the clouds in the dark area are composed of ammonia compounds, called banding.
Ammonium compounds come in various colors: white, orange, brown, but most are reddish-brown.
Saturn
Saturn is a beautiful planet that is the sixth farthest from the sun. Anyone who has seen Saturn through a telescope is amazed. The orbital radius of Saturn is 1.4 billion kilometers, and its maximum brightness is 0.4 magnitude at opposition. Saturn's orange surface is filled with colorful clouds of alternating light and dark colors, coupled with the softly glowing halo on the equatorial surface. From a distance, it really looks like a girl wearing a large-brimmed sun hat.
Saturn rotates once every 10 hours and 14 minutes. Due to the rapid rotation, the equator bulges into an oblate sphere, and the equatorial radius is more than 6,000 kilometers larger than the pole radius. Saturn's revolution period is 29.5 years, which is approximately the number of twenty-eight constellations. It is a constellation for one constellation every year. Therefore, in ancient times, our country also called it the "presence star". Saturn has long been regarded as the boundary of the solar system. It was not until the discovery of Uranus in 1781 that the solar system expanded. Because Saturn moves slowly, people regard it as a symbol of time and destiny. In Roman mythology, he is called the god Saturnus, which is Cronus in Greek mythology. He is the father of the god-king Zeus and ascended to the throne of the gods after overthrowing his father. Both the East and the West associate Saturn with agriculture. The symbol in astronomy is like a scythe that dominates agriculture.
Saturn is second only to Jupiter in size, and they have many similarities. Its diameter is about 120,000 kilometers, 9.5 times that of the Earth; its volume is 730 times that of the Earth. But its average density is smaller than water, only 0.7 g/cubic centimeter. If you put Saturn in water, it will float.
Saturn's internal structure is similar to Jupiter, and it also has a rocky core. The outside of the core is a 5,000-kilometer-thick shell of ice and metallic hydrogen. Outside, it is surrounded by colorful cloud bands like Jupiter. These colorful cloud bands are mainly composed of hydrogen, helium and methane. If the movement of Jupiter's atmosphere is changeable, then the movement of Saturn's atmosphere appears calm, simple and fast. The jet stream on the surface of Saturn can reach a speed of more than 400 meters/second at its fastest. But the real surface of Saturn cannot be seen. What we see are only the cloud tops, whose temperatures are below -200°C.
The Voyager probe discovered 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 have formed due to disturbances and rotation caused by updrafts in Saturn's atmosphere falling back into clouds.
Uranus
It is not difficult to see Uranus on a clear night. Its magnitude is 5.7. Its revolution period is quite long, orbiting the sun once every 84 years, and moving only 46" per day on average. It is not easy to distinguish from stars. It has been mistaken for stars and included in star charts many times in history.
Uranus ranks seventh in the solar system, about 2.9 billion kilometers away from the sun. It is very large, 65 times the size of the earth, ranking third in the solar system after Jupiter and Saturn; its diameter is 5 More than 10,000 kilometers, 4 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 to rule the entire universe--Ula. Uranus. He combined with the earth mother Gaia and gave birth to the future god. He worked hard to make the chaotic universe harmonious and orderly. He was translated into Chinese as Uranus.
Neptune
Neptune ranks eighth in order of average distance from the sun. Its brightness is 7.85 and can only be seen in a telescope. A light blue planet, according to the traditional planetary nomenclature, it is named Neptune. Neptune is the sea god in Roman mythology. He is in charge of 1/3 of the universe and has supernatural powers. Neptune. The astronomical symbol symbolizes the shining cross in Neptune's hand.
Pluto
Pluto is the farthest and smallest planet from the sun. Staggering forward in the cold and dark space 5.9 billion kilometers away from the sun, this situation is very similar to Pluto, the king of Hades who lived in the gloomy underground palace in Roman mythology.
Therefore, people call it Pluto, which in astronomy is the first two letters of Pluto’s English name and the abbreviation of the name of Percival Lowell, the American astronomer who contributed to the discovery of Pluto. .
Pluto is the latest planet discovered. Compared with the discoveries of Uranus and Neptune, the discovery of Pluto can be regarded as a "good thing that takes a long time." Pluto's brightness is very weak, only magnitude 15. Even in photos taken by large telescopes, it is no different from ordinary stars. Finding it among hundreds of thousands of stars is like looking for a needle in a haystack.
During the search for Pluto, Lowell, an American astronomer with a background as an astronomy enthusiast, calculated the position of the unknown planet in detail, used telescopes to search carefully, and spent more than ten years of hard work. Until November 16, 1916, he died suddenly.
In 1925, Lovell's brother donated a large-field photographic telescope with an aperture of 32.5 cm. It had very good performance and provided excellent conditions for continuing to search for new planets. In 1929, the director of Lowell Observatory invited Clyde William Tombaugh to join the search for unknown planets. They searched area after area, took a large number of negatives, and carefully inspected each negative. The work was hard and tedious. On January 21, 1930, Tombaugh finally discovered the new planet in the negatives of the Gemini constellation.
Basic data of Pluto
Mass: 0.0024 Earth mass
Radius: 1350 kilometers
Period: 90465 days
Orbital semi-major diameter: 39.87 astronomical units