Of the eight planets, namely Venus, Saturn, Jupiter, Mercury, Earth, Mars, Uranus and Neptune, Pluto is no longer a planet.

Brief introduction of 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 special 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.

Mercury Feng Guang

The orbit of a star around the sun is a relatively flat ellipse. When it is at perihelion and apohelion, the size of the sun it sees can be more than doubled. The sun moves very slowly in the sky of mercury. If you watch the sunrise on Mercury, you need patience for more than ten hours. Astronomers are very envious of being able to observe the corona and chromosphere carefully for a long time on Mercury, instead of chasing the moment of solar eclipse as on Earth. However, it is impossible to think of mercury. The distance between mercury and the sun is about 1/3 of the distance between the earth and the sun. In addition, the sun's light on Mercury is six times stronger than that on the equator of the earth without atmospheric shielding. Not to mention people, even some metals with lower melting point will melt. In addition, there is neither air nor water on Mercury, and the temperature difference between day and night is very large, reaching 427℃ at the hottest and-173℃ at the coldest. The area with the highest temperature is a basin centered at 30 north latitude and 0/95 west longitude, which is the highest temperature among the planets, hence the name "Calorie Basin", which means "Thermal Basin". Because it is very similar to the "rain sea" on the moon (the name of a basin on the moon), it is also called the "rain sea" on Mercury.

It looks like a moon ball.

Observing Mercury on the ground, you can hardly see its details. 1973165438+1On October 3, the United States launched the Mariner spacecraft 10 to conduct a close-range exploration of Mercury. This is the only spacecraft that has visited Mercury so far. During three meetings with Mercury, it sent back more than 5,000 photos to the ground. For the last time, it was only 372 kilometers away from the surface of Mercury, and it took a very clear TV image of Mercury. Astronomers were surprised to find that the surface of mercury is very similar to that of the moon. The surface of Mercury is littered with craters of all sizes, including mountains, plains and chilling cliffs. According to statistics, there are thousands of craters on Mercury, whose slopes are gentler than those on the moon. 1976, the international astronomical society hired some experts and scholars to name craters. 1987, the first batch of craters were officially announced, among which 15 craters were named after China people. Except Luxun, a great master of modern literature in China, other 14 are ancient writers and artists in China.

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.

One day equals two years.

Mercury revolves around the sun and rotates at the same time. 1889, the Italian astronomer Shapari observed Mercury for many years, and thought that the time of its rotation and revolution was 88 days. People have always believed in this. 1965, American astronomers Pettingill and Deiss, with the help of the world's largest radio telescope at Arecibo Observatory in the United States, measured the frequency difference of reflected waves at the two edges of Mercury, and successfully measured that the rotation period of Mercury was 58.646 days, which was exactly 2/3 of the period of revolution of Mercury. Every rotation of the earth is a day and night, while three rotations of mercury are a day and night. A day and night on Mercury is equivalent to 176 days on Earth. Meanwhile, Mercury has just made two revolutions. So people say that one day on Mercury is equal to two years. Because mercury always faces the sun with the same longitude at perihelion and with a longitude difference of 90 at apohelion, mercury changes seasonally with different longitudes.

Venus introduction

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.

The sun rises in the west. "

People often compare the impossible to "the sun rises in the west", but this sentence is absolutely true on Venus.

Venus is a hidden inverse, which means that it has thick clouds. Inverse means that it is the only planet in the solar system that rotates in the opposite direction. So from Venus, the sun naturally rises in the west and sets in the east, so it is not surprising that "the sun rises in the west".

The thick clouds of Venus blur the daytime on Venus. There are no familiar blue sky and white clouds here, and the sky is orange. It is very interesting that there will be lightning and thunderstorms over Venus, just like over the earth. The rotation period of Venus is 243 days, which is longer than that of period of revolution (224.7 days). A day and night on Venus is equivalent to 1 17 days on Earth. In the year of Venus, the sun can only be seen rising in the west and setting twice in the east on Venus.

Venus probes launched by the United States and the former Soviet Union are equipped with image radar sensors. Radar mapping shows that Venus, like the Earth, is also a planet with very complicated terrain.

Venus is relatively flat because of the protection of dense atmosphere. Venus is 70% flat, 20% low, 10% highland. The largest plateau is twice as large as the Qinghai-Tibet Plateau, with the highest peak 10590 meters, which is higher than Mount Everest. A grand canyon 1200 kilometers long, which runs through the equator from south to north, is the largest canyon among the nine planets. The geological structure of Venus used to be very active, and there are probably active volcanoes. From the investigation results of Venus 13 and Venus 14, it can be seen that the magma inside Venus contains water, which shakes the previous view that Venus is "naturally short of water".

At present, the spacecraft Magellan, the first planetary probe carried by the space shuttle in the history of human space exploration, is mapping more than 90% of Venus landforms with unprecedented visibility, clearly showing the map of Venus in front of people.

Phase transition of Venus

Venus, like the moon, does not shine by itself. The brilliance of Venus comes from the sunlight reflected from the surface of Venus. Venus, like the moon, will have periodic changes. This is because the relative positions of Venus, the Earth and the Sun are constantly changing. The part of Venus illuminated by the sun from the earth is sometimes more or less, which is called phase transition. In fact, all planets in Earth's orbit (such as Mercury) have this change. /kloc-At the beginning of the 7th century, Galileo discovered the phase transition of Venus, which provided strong evidence for Heliocentrism of Copernicus.

Introduction to The Good 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 Seen by Apollo Spacecraft The Earth Seen by Apollo Spacecraft rises on the horizon of the moon and can be considered 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.

Basic data of the earth

The equatorial radius is 6378140m.

Smoothness coefficient 298.257

The mass is 5.976× 1027g.

The average density is 5.52g/cm3.

Surface gravity acceleration (equator) 978.0 cm/s 2

Surface gravity acceleration (polar) 983.2 cm/s 2

The rotation period is 23: 56: 4 (when the sun is flat).

The half-length diameter of the orbit is 149597870 km.

The eccentricity of the orbit is 0.0 167.

Period of revolution 1 sidereal year

The intersection of yellow and red is 23 degrees and 27 minutes.

Introduction to Mars

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.

The surface of Mars

The dry surface of Mars is full of red soil and rocks. Due to the effect of wind and sand, the surface of Mars is covered with sand dunes, and there is a similar riverbed topography. This riverbed topography is distributed in the southern hemisphere and near the equator, indicating that rivers and "water" flowed on Mars about 3 billion years ago, just like on the earth now.

Through the analysis of the composition of Martian topsoil, we know that Martian soil contains a lot of iron oxide. Due to long-term exposure to ultraviolet rays, iron will form a layer of red and yellow oxides. The whole Mars is a rusty world. The features of the surface of Mars are similar. Desolate desert, rolling hills and depressions have been extended to the distance; Rocks dot the surface of Mars, ranging from small pebbles to huge boulders. These are intertwined with the Grand Canyon, the Great Volcano and the potholes, forming a piece of red soil.

Sandstorm on Mars

Another strange thing about Mars is that unimaginable storms blow every year, and the wind speed is indescribable. The wind speed of big typhoons on the earth is more than 60 meters per second, while the wind speed on Mars is as high as 180 meters per second. Great storms sometimes sweep the whole planet. Sandstorm on the surface of Mars is a unique phenomenon in the atmosphere of Mars, and Mars is covered with flying sand for14 of the year. Because of the high iron content in the Martian soil, the Martian dust storm is orange, and the air is full of red dust, which looks like an orange cloud from the earth.

197 1 year, just halfway through the American Mariner 9 Mars probe, the whole of Mars was surrounded by a big sandstorm. The height of 70 ~ 80 kilometers on the surface of Mars is covered with dust, which is too white to be observed. Except for the four potholes vaguely seen near the equator, everything else is very vague and you can't see anything clearly. The sandstorm lasted for half a year before it gradually subsided. This has never happened on earth. It turns out that the four potholes seen during the sandstorm are actually four large volcanoes with a height of more than 25 kilometers. The largest volcano, named Olympus Volcano, is 26 kilometers high and 600 kilometers in diameter, which was formed in nearly 654.38 billion years. Located below the equator is a huge canyon, which is one of the most spectacular landforms on Mars-the Sailor's Valley Grand Canyon. The famous Mariner Valley is 4000 kilometers long, about 300 kilometers wide and 7 kilometers deep. The geological structure of the northern and southern hemispheres of Mars is very different. The great volcano and the grand canyon are both in the northern hemisphere.

The polar cap of Mars

In the telescope, the poles of Mars are white and the temperature is below freezing point. These ice sheets are called polar ice caps. Recently, scientists confirmed that the polar cap is not water ice, but dry ice formed by the condensation of solid carbon dioxide. Its range changes with the seasons from bright areas to dark areas. From the polar regions of Mars to winter, due to the temperature drop, carbon dioxide in the atmosphere begins to condense, which makes the polar cap increase and the color gradually fade. The polar cap can extend to 65 north latitude and the Antarctic cap can extend to 57 south latitude. As soon as the snow and ice melt in summer, the range of polar cap will be reduced, and the dark area will gradually expand and darken. The polar caps of the two poles extend to 80 north latitude and 84 south latitude respectively.

mystery of life

In the past, people thought that Mars was a planet similar to the Earth. The four seasons changed, and the poles were covered with ice, which changed periodically. The existence of ice and snow proves the existence of water, which is the premise of life. Others think that the dark area above Mars may be a plant area. Therefore, the mystery of life on Mars deeply attracts people. In order to explore the secrets of Mars, more than 20 probes have made scientific explorations on Mars in the past 30 years, mainly including American Mariner 9, Viking 1 and Viking 2. These detectors took thousands of photos. Each detector can automatically collect soil samples from Mars for experiments and send the experimental results back to Earth. The experimental results show that there are no rivers, lakes and oceans on Mars, there are no traces of plants, animals or microorganisms in the soil, and there is no intelligent life like "Martians".

199665438+In February, American scientists announced that1the ALH8400 1 meteorite discovered in Antarctica came from Mars. The study of its rock composition shows that these meteorites may contain microfossils of primitive life. This shows that Mars billions of years ago was probably quite warm and humid, suitable for the existence and maintenance of life.

The satellite of Vulcan

Phobos and Phobos run almost on the equatorial plane of Mars. Phobos is 9450 kilometers away from the center of Mars, with a diameter of more than 20 kilometers, and period of revolution is 7.7 hours. Seen from Mars, it rises in the west and sets in the east twice a day. Phobos is about 23,500 kilometers away from the center of Mars, with a diameter of only 15 kilometers, which is 30.3 hours in period of revolution. In the night sky of Mars, you can see the spectacle of "double moon hanging in the sky". 197 1 year, mariner 9 arrived on mars. After the Martian dust storm, Phobos and Phobos were photographed. They look like two "sick potatoes" with craters on the surface and low reflectivity.

Introduction to 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.

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.

In a word, Jupiter has great charm and will fascinate more and more people.

Jupiter stripes

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 ammonia ice with bright colors, which are 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.

Invisible wooden star ring

1 In March, 979, Voyager1sent back a large number of precious photos at a distance of 600 million kilometers from the Earth when crossing the equatorial plane of Jupiter. Surprisingly, both Jupiter and Saturn have rings. Four months later, Voyager 2 flew to Jupiter to confirm this conclusion.

161065438+10 In October, Galileo discovered the four brightest moons of Jupiter. So they are named Galileo satellites. They are surrounded by an orbital belt 400 ~ 1.9 thousand kilometers away from Jupiter. From the inside out are Io, Europa, Garimei and Callisto. They are called io, Europa, Ganymede and Callisto for short.

Introduction of 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. It 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'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.

The most fascinating thing about Saturn is its beautiful light ring.

Galileo observed Saturn with a self-made telescope in 16 10 and found that Saturn had two "ears". He mistakenly thought that Saturn might be composed of three celestial bodies, one big, two small, and suspected that these two ears were two satellites. But he has been afraid to publish the observation results, because the "satellite" does not revolve around Saturn and seems to be stationary forever. What surprised him even more was that the two "satellites" disappeared two years later and reappeared three years later.

The structure of Saturn's rings was discovered from 17 to 19 century. By the early 1980s, at least three probes had a cursory look at Saturn and found that its ring structure was extremely complicated.

According to ground observation and space exploration, Saturn's rings are divided into seven layers. The closest thing to Saturn is the D ring, which is the darkest. Followed by the C ring, the transparency is the highest; Ring b is the brightest; Finally, the a ring. Between ring A and ring B is the famous Cassini ring seam, which is about 5000 kilometers wide. Outside the A ring, there are three rings: E, F and G. The outermost ring is E ring, which is very thin and wide.

After Voyager 1 and Voyager 2 sent back close-up photos of Saturn's rings, scientists were very surprised: it turns out that each layer can be subdivided into thousands of small rings, although there are several small rings in the Cassini seam, which are considered to be empty. In the photo, you can see that the F ring has five small intertwined rings. The overall shape of Saturn's rings is similar to a huge compact record, extending from Saturn's cloud top to 320 thousand kilometers away. The color of the halo is reddish brown from a distance, but in fact each layer is slightly different. The C ring is blue, the inner layer of the B ring is orange, the outer layer is green, the A ring is purple and the Cassini seam is blue.

Introduction to 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

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.

Accidental planet

British astronomer William? Herschel, 178 1 March 13 was in the yard with her sister Caroline at night? When Herschel observed the starry sky with a self-made reflective telescope, she accidentally found a distinctive pale green star in Gemini, and her heart trembled. Which star is it? He asked his sister Caroline to record the observation. After several days of follow-up, he decided that what he found must be a celestial body in the solar system, possibly a comet. So he submitted a paper entitled "Report of Comet" to the Royal Society.

Two years later, the French scientist Pierre-Simon Laplace identified and published William? Herschel discovered new planets in the solar system. Astronomers calculated the orbit of the star outside Saturn. Since then, Uranus, the seventh largest planet in the solar system, has been discovered. The discovery of new planets caused a sensation throughout Europe, and the Royal Society awarded William? Herschel was awarded the copley Medal. At this point, his life has undergone major changes, from an amateur astronomer to a professional astronomer. His life has made outstanding contributions to the development of astronomy, and his achievements go down in history.

primary data

Mass: 8.686×1025kg

Equatorial radius: 25,559 km

Average density:1.29g/cm3.

Average surface temperature: 59K

Surface gravity acceleration (equator): 7.77cm/s2.

Rotation period: 17.9 hours

Angle between equatorial plane and orbital plane: 97.86.

Half-length diameter of orbit: 19. 19 14 astronomical unit.

Period of revolution: 84.0 1 year.

Track eccentricity: 0.046 1

Track inclination: 0.774.

1986 65438+1On October 24th, Voyager 2 found 1 1 rings of Uranus when flying over Uranus at a speed of 72,000 kilometers per hour, and revised the understanding of nine rings. Uranus has 20 rings, and different rings have different colors, adding new luster to this distant planet.

Introduction to Neptune

The average distance from the sun is arranged from near to far, and 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.

Uranus' twin brother

The half-length diameter of Neptune's orbit around the sun is 4.5 billion kilometers, and it takes 165 years to make a revolution. From the discovery of 1846 to today, Neptune has not completed a whole journey. Neptune is 49,400 kilometers in diameter, similar to Uranus, but slightly heavier than Uranus. Neptune and Uranus are mainly composed of hydrogen and helium, and their internal structures are very similar, so Neptune and Uranus are twin brothers.

Uranus has a beautiful light ring. Does Neptune have a halo? This is a question that people are very interested in. 1846 10 at the beginning of this year, British astronomer william russell reported that he had seen Neptune's ring, but was it there? Astronomers have different opinions 1984. American and French astronomers observed the occultation on July 22 at two observatories at the same time, and came to the conclusion that Neptune has a discontinuous ring with a length of only 100 km and a width of only 10 ~ 15 km.

Mercury-mercury mercury

Venus Venus (Roman goddess of love and beauty)

Earth-Earth

Mars-Mars myth (Roman god of war).

Jupiter-Jupiter (Roman God)

Saturn-Saturn Sadus (Rome Saturn)

Uranus-Uranus Uranus (the incarnation of the Greek sky)

Neptune-Neptune (Poseidon, Rome