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Open Category: astronomy, solar system, asteroids, ,],[ 3 http://www. beauty-宝贝疙瘩.com.cn http://magic-u.cn 2 http://www.plbbzs.com http://www.beauty-宝贝疙瘩.com Further reading: 1 http : / / xkcq.lamost.org http://www.souezu.cn/Item/50246.aspx dinosaurs have also died. American scientists in 1991, with the radioisotope method, the measured Gulf of Mexico, Yucatan Peninsula, a large crater (diameter about 180 km) of the age of about 6505.18 million years. Found that the surface crater from the point of view, there is likely to occur every three million years for the 500-meter diameter asteroid hitting the Earth event. Greater probability of an asteroid strike, even smaller. Probability of an asteroid hit the Earth may hit the Earth in 2014 is 90 parts per million chance BEIJING, Sept. 3, 2003 Xinhua research arm of the United Kingdom and the United States, warned that an asteroid could hit Earth in 2014, but the probability is 90 more than a million. According to the BBC news, the British government's Near Earth Objects Research Center, said the U.S. astronomers discovered a size However, scientists estimate, 杩欓 known as They further pointed out one after another to collect the latest data show that the risk of potential impact will continue to decline. Although the probability of the asteroid hitting Earth is very low, based on the volume of Fengyun small trekking and speed, it is worth it for the scientists observed. This However, its speed is 20 miles per second, per minute at up to 120 miles. As the speed quickly, and if hit Earth, it can have catastrophic effects on Earth. U.S. astronomers will be closely observed in the next two months, Asteroid hit the Earth in the eyes of the artist scene of a British space expert has said that a giant asteroid named 2002 NT7 will hit the Earth 17 years, when life on Earth will suffer a devastating blow. The asteroid was allegedly detected so far the biggest threat to the Earth objects, its diameter about two kilometers, is expected to hit speeds of up to 28 kilometers per second, regardless of colliding with the Earth in any one place on five continents, are sufficient to destroy block the entire continent and cause global climate upheaval. Atlas Atlas entry for more reference materials 1 asteroid : The asteroid 75百分之百 of all asteroids, and therefore the largest number of asteroids. C-asteroid's surface carbon, albedo is very low, only 0.05 or so. Generally believed that the composition of C-asteroids and carbonaceous chondrite (a stony meteorite) the composition of the same. General C-asteroids are distributed in the outer asteroid belt. S-Asteroids: The Asteroids for 17百分之百 of all asteroids is the second most asteroids. S-asteroids generally distributed in the inner asteroid belt. S-asteroid albedo is relatively high, from 0.15 to 0.25. Their composition and similar to ordinary chondrites. Such meteorites are generally composed of silicide. M-Asteroids: Most of the rest of the asteroids fall into this category. These asteroids may be relatively large asteroids in the past the metal core. Their albedo and S-like asteroids. They may be related to the composition of nickel - iron meteorite similar. E-asteroids: asteroid's surface mainly by this type of enstatite composition, their albedo is relatively high, generally above 0.4. They may be related to the composition of enstatite chondrites (another type of stony meteorite) is similar. V-asteroids: This very rare asteroid composition and S-asteroid almost, the only difference is that they contain more pyroxene. Astronomers suspect that these asteroids Vesta is in the upper separated silicide. The surface of Vesta has a very large crater, possibly formed in the course of its V-asteroid was born. Occasionally, the earth is very rare to find a stony meteorite, HED-non-chondrites, their composition may be similar with the V-asteroids, they may also come from Vesta. G-asteroids: they can be seen as a kind of C-asteroids. Their spectra are very similar, but in the ultraviolet part of the G-asteroids have different absorption lines. B-asteroids: they and G-C-asteroids and asteroids are similar, but different UV spectrum. F-asteroids: asteroid is a C-. Spectrum in the ultraviolet part of their different absorption lines and the lack of water. P-Asteroids: These very low albedo asteroids, but mainly in the red part of its spectrum. They may be caused by the composition of carbon silicide. They are generally located in the very outer asteroid belt. D-asteroid: P-type asteroids and the asteroid is similar to a very low albedo, spectral red. R-asteroids: V-type asteroids and the asteroid is similar to their spectra that they contain more pyroxene and olivine. A-asteroids: asteroid with a lot of this type of olivine, which, mainly in the inner asteroid belt. T-asteroids: the distribution of these asteroids in the asteroid belt lining. Their spectrum of dark red, but with the P-and R-asteroids of different asteroids. The past people thought that the asteroid is a complete single stone block, but the asteroid's density, lower than the stone, and they are huge craters on the surface of the ,Tiffany Charms, larger asteroids that organization is relatively loose. They are more like the enormous combined gravity rubble. This loose objects would not impact the large fragmentation, and can impact energy absorption over. Complete a single object in a large shock wave will be crushed under impact. In addition a large asteroid's rotation speed is very slow. If the rotation speed of their high, they may be centrifugal disintegration. Today, astronomers generally believe that asteroids larger than 200 meters is mainly composed of this rubble. And some smaller fragments of asteroids have become some of the satellite, for example: it has two satellites 87 asteroids. Probe into the age of space travel before the asteroid even the largest telescopes in the only spot the size of a needle, so their shape and topography are still unknown mystery. The first is to o变态ain close-up asteroid 1971 Mariner 9 photographed Fu Boss and Dai Mosi photo, the two small bodies, though they are a satellite of Mars, but may have been asteroid captured by Mars. These images show "cczwqmddn",Cheap Tiffany Jewelry, that the majority of the asteroid with irregular shapes like a potato. Voyager program after the gas giant plans to get more small satellite images. The first true asteroid close-up to Jupiter by the Galileo spacecraft flying in 1991, passing the 951 Gaisipula (Gaspra), then 243 in 1993 and his actress Ai satellite set g Pacific (Dactyl). The first dedicated asteroid probe space program is the rendezvous - Shoemaker Road, he was on his way to 433 Eros, taken in 1997 show de 253 M (Mathilde), in orbit around the probe after the completion, in 2001 The successful landing on the Eros. Once the spacecraft in the other head to the flight of asteroids briefly visited there 9969 Blair (Braille) (Deep Space 1 in 1999) and Anne Frank (Annefrank) (Stardust in 2002). In September 2005, the Japanese spacecraft Hayabusa arrived at 25143 Itokawa in detail the detection, and may bring back some samples back to Earth. The Hayabusa mission has encountered some difficulties, including three guide wheels bad, two, makes it hard to maintain the direction of the sun to collect solar energy. The next asteroid detection program is the European Space Agency's Rosetta (launched in 2004), expected in 2008 and 2010 Year 2867 艩teins detection and 21 Lutetia. In 2007, the National Aeronautics and Space Administration launched the Dawn spacecraft will be in 2011 and 2015 around Ceres and Vesta, and may extend the mission to probe the Pallas. Asteroids have been proposed as the future use of Earth resources, the mining of raw materials as a rare field, or open space station construction materials. Launch from Earth is very cumbersome and expensive materials, the future may be able to directly from the space located in the asteroid factory direct manufacturing and mining. Asteroid belt asteroid orbit about 90百分之百 of known asteroids orbit in the asteroid belt. Asteroid belt is located in a fairly wide zone between Mars and Jupiter. Ceres, Pallas and so the first to be found within the asteroid belt asteroids are asteroids. Mars orbit of the asteroid asteroids within the orbit of Mars is divided into three general groups: Amor-type asteroids: asteroids cross the orbit of Mars in this category, and came near the Earth's orbit. The representative of the asteroid was discovered in 1898 asteroid 433 asteroid from the Earth can reach a distance of 0.15 astronomical units. 1900 and 1931 near Earth asteroid 433 astronomers to use this opportunity to determine the size of the solar system. 719 asteroids discovered in 1911 and later disappeared, until 2000 it was rediscovered. Group named the asteroid 1221 Amor asteroids orbit of stars from the Sun in astronomical units from 1.08 to 2.76, which is fairly typical of this group as a track. Apollo asteroids: asteroid groups of asteroids that orbit between Mars and Earth. Some of the group orbital eccentricity of the asteroid is very high, they have reached perihelion inside the orbit of Venus. Typical of this group of asteroids orbit asteroids are discovered in 1932, Apollo 1862, its orbit in between 0.65 to 2.29 astronomical units. Asteroid 69230 is only 1.5 lunar distances in the fly a little earth. Aten asteroids: asteroid's orbit in this group generally less than in Earth orbit. Star named asteroid discovered in 1976, 2062 Arden. Some of this group,Tiffany Bracelet, is relatively high eccentricity of the asteroid, they may be from Earth orbit to cross the Earth orbit. These asteroids are collectively referred to as the near-Earth asteroids. In recent years, studies of these asteroids are better because they at least theoretically possible to collide with Earth. Compared results of the project are the Lincoln Near-Earth Asteroid Research Program (LINEAR), Near-Earth Asteroid Tracking (NEAT) and the Lowell Observatory Near-Earth Object Search program (LONEOS) and so on. In the other planets orbit the asteroids in the Lagrangian points of the other planets orbit the asteroid is called on to run the Trojan asteroids. First to be found in the Jupiter Trojan asteroids orbit asteroids, some of them before in Jupiter, some run after Jupiter. Jupiter's Trojan asteroids representative and asteroids are asteroids 588 1172.1990 on a Mars Trojan asteroid 5261 asteroid was discovered, then there are other four Martian Trojan asteroids have been discovered. Asteroid between Saturn and Uranus, Saturn and Uranus is among a group of asteroids known as the Centaur asteroids asteroids, and their eccentricities are quite large. Centaur first asteroid discovered asteroid 2060 asteroid group. Estimated that these asteroids in the Kuiper belt from the gravitational interference by other planets fall into an unstable orbit. Kuiper Belt asteroid belt: full name Yiji Worth - Kuiper Belt (English: Edgeworth-Kuiper belt; EKB, generally referred to as the Kuiper Belt, Kuiper Belt or translation, Cooper band, etc.) yellow dot ring as the Kuiper Belt ( Kuiper Belt) TNOs and similar objects: Centaurs TNOs Kuiper asteroid belt object class offerings in the object class QB1 2:1 resonant objects Scattered disc objects Oort cloud beyond Neptune Oort Kuiper belt asteroids are, where astronomers found that the largest asteroids, such as asteroids 50000 and so on. Asteroids within the orbit of Mercury (water within the asteroid) Although there has been some speculation within the orbit of Mercury also has an asteroid group, but so far not confirmed this speculation. [Line into] some distance from the near-Earth asteroids close to Earth, they had some small meteorites but after suck the Earth is gravity, which is near-Earth asteroids. Collision asteroid collision that said that: about 65 million years ago, about a kilometer in diameter asteroid collision with Earth, a violent collision rolled up a lot of dust, so that the earth's atmosphere is filled with dust and gathered into a dust cloud, a thick cloud of dust enveloped the entire planet over, blocking the sun, the earth a The lack of sunlight, the survival Tiffany Jewelry Outlet, of plant photosynthesis have been destroyed, a large number of plants have withered and died, a large herbivorous dinosaur body consume each day a few h,Tiffany Sets, undred kilograms of dry plants, they simply can not adapt to this flare-up causes variation of the living environment, and only in the starvation and hopelessness to fall; to herbivorous dinosaur meat for food sources asteroid quality even smaller than the moon. Astronomers believe that today the formation of asteroids in the solar system there is no residue to form planets. Jupiter in the solar system formed when the quality of the fastest growing, it prevents the asteroid belt region today the formation of another planet. Asteroid belt region of the asteroid orbit by Jupiter's interference, they continue to impact and crushing. Other substances were driven out of their orbits collided with other planets. Large asteroid in the formation of radioactive isotopes of aluminum after the 26Al (radioactive isotope of iron and possible 60Fe) the decay of hot. Heavy elements such as nickel and iron in this case sank to the asteroid's interior, light elements such as silicon is floating. As a result of the asteroid on the separation of the internal material. In the subsequent collision and produced by the breakdown of the new composition of the asteroid and therefore different. Some of these pieces was a meteorite landed on Earth. Structure of the data o变态ained by spectral analysis of the asteroid's surface composition can prove very different. The characteristics of their spectral types of asteroids are divided: C-asteroid planet with 15000 CCD 17000 Medvedev (exception) 21000 20000 Varuna encyclopedia boast aure 25000 56000 50000 astrometry Mesopotamia 71000 Hughdowns (exception) because permanent number has more than 100,000, some of the original program to cope with five numbers can not support, so there are some letters in ten thousand with the number of representation, that is, A = 10, B = 11 ... ... Z = 35; a = 36 ... ... z = 61, in this arrangement, the 619,999 the following number of asteroids that can still be used 5. Well-known part of the asteroid with the Chinese on Chinese soil on the first one discovered asteroid: 139 Jiuhua stars (Juewa) (discoverer JC Watson) its first asteroid discovered by the Chinese people: 1125/3789 Chinese (China) (discoverer Zhang Yu Zhe, after the 1125 changes to 3789) the first one in China, named after the asteroid: 1802 Zhang Heng (Zhang Heng) (Purple Mountain Observatory, discoverer) its first asteroid named after Chinese: Beijing 2045 ( Peking) (Purple Mountain Observatory, discoverer) first named a county of China's asteroid: 3611 Tai Po (Dabu) (Purple Mountain Observatory, discoverer) to its first asteroid named after the people of Taiwan: 2240 Cai (Tsai ) (Tsai, Xian) (discoverer of the Harvard Observatory) spacecraft, the first one to name the asteroid China: 8256 Shenzhou (Shenzhou) (Purple Mountain Observatory, discoverer) of Hong Kong secondary school students in recognition of the invention Chan Yik-hei's achievements in the name of the asteroid: 20780 Chan Yik-hei stars (Chanyikhei) (discoverer LINEAR team), named to commemorate the Beijing Olympic Games: the 2008 Beijing Olympic star formation, the beginning of the asteroid Ida is an asteroid that astronomers in the planet between Mars and Jupiter from rupture , but all the asteroids in the asteroid belt's total mass asteroid asteroids are at the traditional God of the Roman or Greek to name, such as Pallas, Vesta, Astraea and so on. However, as more and more asteroids were found, the last classical names of God used up. So was the wife of the discoverer of asteroids with the names of historical figures or other important people, cities, fairy tale characters and the name of God or other mythology named. Such as asteroids Clio 216 is based on the Egyptian queen named Petra, asteroid 719 Albert was named by Albert Einstein, asteroid 17744 was named by actress Jodie Foster's , asteroid 1773 is based on the Brothers Grimm a dwarf named, and so on. As of March 6, 2007, has calculated the orbit (that is, by the temporary number) a total of 679,373 pieces of asteroids (query), number of asteroids have been a total of 150,106 permanent teeth (query), the asteroid has been named a total of 12,712 pieces. For some number is a multiple of 1000 asteroids, it is customary to particularly important people, things to name. (But occasional exceptions) such as: number is a multiple of 1000 asteroids have been named Herschel 3000 1000 Pia Qi Da Vinci 4000 2000 5000 Hipparch,Tiffany Rings, us 7000 United Nations, the International Astronomical Union Curie 8000 6000 Newton 9000 HAL ( exceptions) 10000 Myriostos (exceptions) asteroid asteroid after the formation of the aluminum in the radioisotope 26Al (radioactive isotope of iron and possible 60Fe) of the decay and heat up. Heavy elements such as nickel and iron in this case sank to the asteroid's interior, light elements such as silicon is floating. As a result of the asteroid on the separation of the internal material. In the subsequent collision and produced by the breakdown of the new composition of the ,Tiffany Watches, asteroid and therefore different. Some of these pieces was a meteorite landed on Earth. Overview of C-type asteroid named 253 Mathilde asteroid's name consists of two parts: the front part of a permanent number, a name is part of the back. Each tablet was first confirmed asteroid will be a permanent number, discoverer of the asteroid can suggest a name. The name to be approved by the International Astronomical Union was formally adopted, because the naming of asteroids have a certain routine. Therefore, some asteroids have no names, particularly in the permanent number in the tens of thousands of asteroids. If the asteroid's orbit can be determined accurately enough, then even if it is confirmed that. Prior to this, it will have a temporary number, it is found that by the year and two letters, such as the 2004 DW. Pia Qi is the first asteroid was discovered in 1801 in Sicily, he gave the stars named Ceres Ferdinand stars. The first part is the patron saint of Sicily, named Ceres, is the latter part of King Ferdinand IV of Naples named. However, this international scholars are not satisfied, so the second part removed. So the first official name of an asteroid is an asteroid 1 Ceres. Since then discovered the asteroid Ida It is. October 1991, Galileo Jupiter probe visited the asteroid 951 Gaspra, the first high-resolution shot of the asteroid photos. August 1993, Galileo flew another asteroid 243 Ida, making it the second pieces of asteroids visited by spacecraft. Asteroids Gaspra and Ida are rich in metals, are S-type asteroids. June 27, 1997, NEAR asteroid 253 Mathilde pass detector. This rare opportunity allows scientists to closely observe the first Fengyun C-type asteroids are rich in carbon. NEAR detector because its not a special inspection that the visit be carried out so far its only visit. NEAR is used in the January 1999 inspection of the asteroid Eros. Ground observation of many asteroid astronomers have made the ground observation. Some well-known asteroids have Toutais, Castalia, Vesta, and Geographos and so on. For the asteroid Toutatis, Castalia, and Geographos, astronomers in their proximity to the sun, on the ground through the observation of their radio. Vesta asteroid was discovered by the Hubble Space Telescope. From the beginning of the astronomers that the asteroid is a planet between Mars and Jupiter from broken, but all the asteroids in the asteroid belt's total mass much smaller than the quality of the moon. Astronomers believe that today the formation of asteroids in the solar system there is no residue to form planets. Jupiter in the solar system formed when the quality of the fastest growing, it prevents the asteroid belt region today the formation of another planet. Asteroid belt region of the asteroid orbit by Jupiter's interference, they continue to impact and crushing. Other substances were driven out of their orbits collided with other planets. Large asteroid line, it is easy to be determined. Moreover, with the film's sensitivity to enhance their soon to be sensitive than the human eye, even darker asteroids can be found. The introduction of photography made was found a huge increase in the number of asteroids. 1990 charge-coupled device photography technology has been introduced, together with computer analysis of electronic photography technology have improved the asteroid makes more in a very short period of time was found. Today, the number of known asteroid about 22 million. The orbit of an asteroid has been identified, astronomers can brightness and albedo of its analysis to estimate its size. In order to analyze the albedo of an asteroid astronomers generally use both visible light is also used infrared measurements. However, this method is less reliable, because each asteroid's surface structure and composition may differ, so the albedo of the errors are often relatively large. More accurate data can be used to o变态ain radar. Astronomers use radio telescopes as a generator of high power radio waves to the strong projection of the asteroid. By measuring the reflected wave reaches the speed of asteroid's distance can be calculated. On other data (diffraction data) of the asteroid can be deduced from the shape and size. In addition, the observed asteroid occultation can be more precise to calculate the asteroid's size. Non-manned spacecraft studies of asteroids now have a series of non-manned spacecraft around the asteroid in a number of them have studied: in 1991 Galileo Jupiter in its distance on the fly flying to the asteroid 951 , 1993, asteroid 243 fly. NEAR asteroid No. 253 flew in 1997 and in 2001 landed at the asteroid 433. 1999, Deep Space 1 asteroid flyby in 9969, 26 km away. In 2002, Stardust flew by asteroid 5535 3300 km distance. Because asteroids are left over from the early solar system material, scientists are very interested in their composition. After space probe found the asteroid belt, asteroid belt is actually very spacious, the distance between the asteroid and the asteroid is very far away. Prior to 1991, it is through ground-based observations to o变态ain the number of asteroids asteroid 邮件群发 In January 1801 the first day, Giuseppe Piazzi discovered an object, at first he thinks it will not again be a comet. But when it was determined orbit, they found it was not a comet, but rather is a small planet. Piazzi called Ceres (Ceres, goddess of grain and farming is grain beauty of Sicily), also known as Ceres. The other three small bodies also were found in successive years (they are Pallas, Vesta, and Juno). The nineteenth century have been discovered a few hundred. Has been found more than 7,000 asteroids, and now this figure is still an annual growth rate of a few hundred. No dou变态, there must be hundreds of asteroids as too small to observe on Earth. For now known, there are 26 asteroids of diameter greater than 200 km. Of these visible observations of asteroids have been basically completed, to our knowledge, about 99百分之百 of the asteroid's diameter is less than 100 kilometers. For those 10 to 100 km in diameter asteroid between the catalog has been completed in half. But we know there are some smaller, perhaps there are nearly one million of around 1 km in diameter asteroid. The quality of all the asteroids and the quality of the moon is smaller than [1]. Early speculation that the study of history in 1760 there was speculation within the solar system planets distance from the sun to form a simple number series. By the series between Mars and Jupiter there is a gap between these two planets should have a planet. The late 18th century, many people started looking for Fengyun undiscovered planets. Well-known Titius - Bode is set is one example. European astronomers at the world's first international organization of research projects, under the leadership of the Observatory in Gotha day is divided into 24 districts, the European astronomers who systematically search the area in the 24 Fengyun known as the But this project without any result,Tiffany Cufflinks, s. Pia Qi findings January 1, 1801 the evening, Zhu Se Pupi Aceh Palermo Observatory in Sicily were found in the inner Taurus in the chart can not find a star. Pia Qi I did not participate in looking for He will report his findings to the Gotha Observatory, but at first he said he found a comet. This Houpi Ya Qi sick, unable to continue his observations. And report his findings to the use of a very long time Da Geda, this time the star has been direction to the sun, can not be found. At this point the research Gauss Gauss invented a method of calculating orbits of planets and comets method, this method requires only a few points we can calculate the position of a celestial body's orbit. Pia homogeneous Gaussian read after the discovery of the location of the object calculated Fengyun sent Gotha. Olbers on the evening of 31 December 1801 re-discovered the star. Later it acquired the name Ceres. 1802, Olbers discovered another one objects, he named it Pallas. 1803 Juno, Vesta was discovered in 1807. Until 1845, the fifth asteroid Astraea was discovered, but since then many asteroids were soon discovered. 1890 so far have been about 300 known asteroids out. Photography into astronomy photography into astronomy in 1890 for the development of astronomy given a huge boost. Prior to discover an asteroid astronomers have suspected for a long time record of each star's position stars, compare them with the changes between the location of the surrounding stars. However, photographic film, on an asteroid relative to the movement of stars on the film pulled out a asteroid found Ceres close to the sun, on the ground by radio observations of them. Vesta asteroid was discovered by the Hubble Space Telescope. The discovery of asteroids with the Titius - Bode set is closely linked to the proposal, according to the set is, at a distance of 2.8 astronomical units from the sun should be a planet at the 1801 New Year's Day Piya Qi is really found in the area the first asteroid Ceres. In the following years with a similar orbit Ceres Pallas, Juno, Vesta have been found. The introduction of astronomical photography and flash, as the comparator, it allows the discovery of the asteroid's rate rose significantly, to 1940, with a permanent number of asteroids have been 1564. Among them, the German astronomer Encke and longer than the orbital calculations by Hansen, Wolf and Laiyinmute the observation that there are many contributions to the discovery of particularly great. Asteroid naming rights belong to the discoverer. Early like to use the name of the goddess, and later switched names, nickname and even the organization name of the acronym to name. Some asteroids and the asteroid is very famous, such as off Loyang group, Apollo Group, Icarus, Eros, Hedo Hidalgo and so on. By Orbital for statistical analysis, at about 5 degrees inclination and eccentricity of about 0.17 the largest number of asteroids. Kirkwood gap is based on the average heliocentric distance of the asteroid by the best-known statistical distribution. N and the average number of red asteroid magnitude m at the statistical relationship between the logN = 0.39m-3.3, an asteroid with diameter d between the absolute magnitude of g satisfy the statistical formulas logd (km) = 3.7-0.2g. The distribution of the number of asteroids with diameters of about 30 km in diameter near the discontinuity. Ceres Number of asteroids may be about 50 million. The largest asteroid is only about 1,000 km in diameter, miniature asteroid the size of pebbles only. Diameter of more than 240 km asteroid about 16. They are located inside Earth's orbit to the orbit of Saturn, the outer space. The vast majority of asteroids are concentrated in the orbits of Mars and the asteroid belt between Jupiter. Some of the asteroid's orbit and the Earth's orbit intersect, there have been some of the asteroid collision with Earth occurred. Asteroids are remnants of the material after the formation of the solar system. There is a speculation that they may be the remains of a mysterious planet, the planet in ancient times suffered a huge cosmic collision destroyed. However, the characteristics of these asteroids of view, they do not like once assembled together. If all the asteroids put together to form a single object, then it's less than 1500 km in diameter - smaller than the radius of the moon. Since the early solar system, asteroids are material, the scientists are very interested in their ingredients. After a space probe found the asteroid belt, asteroid belt is actually very open, asteroids and the asteroid separated very far between. In 1991, the asteroid before the data o变态ained only through ground-based observations. October 1991, Galileo Jupiter probe visited the asteroid 951 Gaspra, which won the first high-resolution photographs of asteroids. August 1993, Galileo flew by the asteroid 243 Ida, making it the second pieces of asteroids visited by spacecraft. Asteroids Gaspra and Ida are rich in metals, are S-type asteroids. We know many of asteroids falling to Earth's surface through the analysis of space rubble. The asteroid that collided with the Earth as meteorites. When high-speed meteoroid broke into our atmosphere, its surface due to friction with the air temperature and evaporation, and glared, this is the meteor. If the meteoroid is not completely burned and fell to the ground, then known as meteorites. After analysis of all the meteorites, of which 92.8百分之百 of the composition is silicon dioxide (rock), 5.7百分之百 iron and nickel, the remainder is a mixture of these three substances. Stone meteorites with known large meteorite, a large quantity of iron meteorites called siderite. Because meteorites and Earth rocks are very similar, so difficult to identify. June 27, 1997, NEAR asteroid 253 Mathilde pass detector. This opportunity allows scientists to closely observe the Fengyun first carbon-rich C-type asteroids. Visit the NEAR detector is not designed to study them and become the only one visit. NEAR is used in the January 1999 inspection of the asteroid Eros. Astronomers have already made a lot of ground observation of the asteroid. Some well-known asteroids have Toutais, Castalia, Vesta, and Geographos and so on. For the asteroid Toutatis, Castalia, and Geographos, astronomers in their asteroids Gaspra and Galileo spacecraft 002 years of glory found in Norbert Ore (Quaoar) diameter is 1280 kilometers, discovered 2004 DW 2004, even up to 1800 kilometers in diameter. Discovered Sedna in 2003 (asteroid 90377) is located outside the Kuiper Belt, its diameter is about 1,500 km. According to estimates, the number of asteroids may be about 50 million. The largest asteroid is only about 1,000 km in diameter, miniature asteroid the size of pebbles only. The largest asteroid now reclassified to be defined as a dwarf planet. Diameter of more than 240 km asteroid about 16. They are located inside Earth's orbit to the orbit of Saturn, the outer space. The vast majority o,Tiffany Pendants, ,Tiffany Earrings, f asteroids are concentrated in the orbits of Mars and the asteroid belt between Jupiter. Some of the asteroid's orbit and the Earth's orbit intersect, there have been some of the asteroid collision with Earth occurred. Asteroids are remnants of the material after the formation of the solar system. There is a speculation that they may be the remains of a Tiffany Accessories, mysterious planet, the planet in ancient times suffered a huge cosmic collision destroyed. However, the characteristics of these asteroids of view, they do not like once assembled together. If all the asteroids put together to form a single object, then it's less than 1500 km in diameter - smaller than the radius of the moon. So far in the solar system have found a total of about 700,000 asteroids, it could be all the asteroids is only a small part, only a few of these asteroids larger than 100 kilometers. Until the 1990s was the largest asteroid Ceres, but in recent ye,Tiffany Necklaces, ars found some of the Kuiper belt asteroid Ceres, the diameter is larger than, for example discovered in 2000 Varuna (Varuna) 900 km in diameter, 2002 Norbert Ore found in Quarry (Quaoar) diameter is 1280 kilometers, discovered 2004 DW 2004, even up to 1800 kilometers in diameter. Discovered Sedna in 2003 (asteroid 90377) is located outside the Kuiper Belt, its diameter is about 1,500 km. According to estimates, asteroid Toutatis Introduction to the History of early speculation that the discovery of homogeneous Gaussian Pia research into astronomy, photography unmanned spacecraft on the asteroid named an overview of sources of ground observation number 1000 multiples of some asteroids have been named with the Chinese on the formation of structures known asteroids orbit the asteroid belt asteroid probe orbits Mars on other planets within the asteroid orbit asteroid collision asteroid that hit Earth Introduction chance asteroid, minor planet or planetoid in the solar system planets around the sun like sports, but the volume and quality of much smaller objects than planets. So far in the solar system have found a total of about 700,000 asteroids, it could be all the asteroids is only a small part, only a few of these asteroids larger than 100 kilometers. Until the 1990s was the largest asteroid Ceres, but in recent years found some of the Kuiper belt asteroid Ceres, the diameter is larger than, for example discovered in 2000 Varuna (Varuna) 900 km in diameter, 2 < p> Asteroid directory 锘?p> asteroid (asteroid) is similar to the solar system planets around the Sun campaign, but much smaller volume and mass ratio of planetary objects. Most asteroids in our solar system orbit between Mars and Jupiter called the asteroid belt. Also outside the orbit of Neptune is also the distribution of asteroids, this area called the Kuiper belt (Kuiper Belt).