Solar system a collision event

<wbr> <p> Solar system <wbr> www.thebeijingnews.com collision events · 2008-1-1310: · 23: 16 Source: Beijing News </ p> <p> <wbr> </ p> <p align .= "center"> </ p> <p> <wbr> </ p> <p> Recently, astronomers a series observations speculated that a spatial impact may well after 10 days. </ p> The performance of the protagonist is a .numbered asteroid 2007WD5. It is possible this month, 30, hit Mars. 2007WD5 diameter of about 50 m, impact will produce the equivalent of 300 million tons of TNT explosive energy. If this event occurs, will become the human study asteroids and space impact .of important samples. <p> <wbr> </ p> <p> 1 impact probability: 3.6% </ p> <p> <wbr> </ p> <p> This asteroid numbering is 2007WD5. </ p> .November 20, 2007, in the United States, Arizona, near the city of Tucson, Italy astronomers Boattini (AndreaBoattini) with a diameter of 1.5 m telescope implementation of NASA (NASA) in a search. This task began in 1998 with the aim of .monitoring all the possible impact earth asteroid. On this day, Boattini found a later named "2007WD5" asteroid. <p> <wbr> </ p> <p> Soon, astronomers discovered that this asteroid has in November 2007, and the Earth .. </ p> However, it is to fly to Mars, and possibly in 30 January hit Mars. <p> <wbr> </ p> <p> 21 December last year, NASA astronomers Chesley (SteveChesley) after the projection that .the collision probability in 1.33%. </ p> Then, astronomers discovered back in early November, is located in the United States Mexico Apache point Observatory telescope has photographed some of the image. 2007WD5 They will show these images included in the calculation of the .data and found that the likelihood of collision rose to 3.9%. Astronomers continue watching this dangerous "wanderers". 2008 new year's day, Magdalena Mountain Observatory a diameter 2.4 m telescope acquire some new observational data. As a result, the collision probability be overwritten .for current 3.6%. <p> <wbr> </ p> <p> At present, the asteroid is moving away from Earth, this increases the difficulty of observation. </ p> However, scientists still hope to continue to receive new .observational data to better observe the possible impact. In the coming weeks, all United States Hawaii Island diameter 2.2 m telescope and the United States, Arizona, MMT Observatory telescope 6.5 meters in diameter will be put into the search. <p> <wbr> .</ p> <p> National Observatory researcher Li Jing pointed out that the asteroid hitting Mars event is not nothing new. </ p> The Earth's surface is at least 140 craters of the Moon, of which more than 90 were knocked out of .the asteroid. However, these impacts are basically takes place in the solar system formation in the early years. Beijing Astronomical Observatory associate researcher David explained, "we see the crater some have millions of years of history." <p> <wbr> < ./ p> <p> NASA near-Earth object program leader Dan · Yeomans pointed out that, in General, through more observation data correction, the probability of impact will disappear. </ p> This time the impact hypothesis may also be the case .. <p> <wbr> </ p> <p> 2 never get rid of the threat </ p> <p> <wbr> </ p> <p> As of November 21, 2007, the International Centre has to .asteroids 735942 conducted a number of asteroids, asteroid obtained permanent 171475, 14226 asteroid named received. </ p> <p> <wbr> </ p> <p> These asteroids will run around the day. </ p> They are largely .concentrated in the orbits of Mars and Jupiter, orbiting, averaging approximately half the track length diameter is 2.8 astronomical units, the same day and the average distance of 2.8 times. <wbr> "There are also some special asteroids orbit, such as in the .Sun than Neptune more distant orbit 'Kuiper belt' of the celestial bodies, as well as track can reach the Earth's orbit around the 'near-Earth asteroids'. "Beijing Planetarium Director Jin-pointed out. The so-called near-Earth asteroids ., refers to the running rail and close to the Earth's orbit, even intersect the asteroid. They are threatening the security of the Earth. <p> <wbr> </ p> <p> Zhu Jin said, according to its orbit astronomers the .different features of the near Earth asteroid into three categories: Roatan-(Aten), Apollo-type (Apollo) and Amor (Amor). </ p> As of November 24, astronomers have found near Earth asteroid 4251. If an asteroid's orbit .and the Earth orbit distance less than 0.05 astronomical units (about 750 million meters), and absolute magnitude brighter than 22, etc., are considered "potentially hazardous asteroids". Such an asteroid at least 810. Some astronomers believe that one known as the .Dreyfus Awa (Apophis) is likely to be in 20 years after the encounter with the Earth. <p> <wbr> </ p> <p> Why the asteroid will pass from the asteroid belt, invading the Earth's orbit? asteroid "derailment ."there are two main ways. </ p> <p> <wbr> </ p> <p> First, the impact. </ p> If the asteroid collision between, some of which will change the original tracks, or even .be playing near the Earth. <p> <wbr> </ p> <p> The second is gravity. </ p> Some asteroids and giant Jupiter revolves around the Sun's cycle formation simple proportional relationships, such as Jupiter's revolution around the time .the revolution of a planet just three laps, then they formed the "orbital resonance". In this case, the moons of JupiterGravity will be on this planet have a significant impact to track deformation and gradually invade the Earth orbit. <p> <wbr .> </ p> <p> Beijing Planetarium Director Jin-is further noted that the source of near-Earth asteroid more complex. </ p> "In fact, an asteroid at run time, subject to the influence of various celestial bodies gravity ., these factors will affect the evolution of the asteroid's orbit. "<p> <wbr> </ p> <p> 3 the asteroid that elusive? </ p> <p> <wbr> </ p> <p> In .order to prevent asteroid impact Earth, some countries have already started the asteroid observing projects. </ p> The most important of which is NASA's space defense survey program, a $ 400 million per year by large observation plan, major work was the search for .Earth diameter near the small body of several kilometers. <p> <wbr> </ p> <p> Although a sophisticated monitoring system, but astronomers still don't know whether the asteroid will hit Earth. </ p> <p> .<wbr> </ p> <p> At the end of 2004, astronomers gave people a bad news. </ p> They found a name of "Dreyfus Awa" asteroid. This asteroid with a diameter of about 250 meters. Worse, .astronomers calculate that 1% could hit the Earth in 2029. Further projected to impact probability to about 3%. However turn soon appear, now, a growing number of astronomers think "Dreyfus Awa" does not pose a threat to Earth. To the year .2029, it will rub shoulders with the Earth. <p> <wbr> </ p> <p> Why asteroids so elusive? Li Jing explained that this is not the same as astronomers speculate asteroid orbits of the method. </ p> .<p> <wbr> </ p> <p> In observing, if astronomers observed within ten days to three different operating points, they would form a paragraph, and then run an arc pursuant to this section of the arc projection out asteroid orbits .. </ p> "If this arc is shorter, derived from the rough running track; the longer the arc, the track more accurately," Li Jing pointed out that, as the astronomers continue in-depth observations with an asteroid's orbit will have .different big face before and after, it increased the forecast asteroid will hit Earth. <p> <wbr> </ p> <p> In addition, the current observation system for those who have a diameter less than 100 meters of small celestial bodies .or his ambition. </ p> And once found, these small celestial bodies have also been very close from the Earth, then take measures also weakness. In 1998, the United States Congress asked NASA selected diameter over 1 km of near-Earth asteroid .. They have destroyed most of life on Earth. After the inventory, astronomers found near Earth asteroid only 200. However, also some heads smaller asteroids, the greater their number. These asteroids are diameter 100-1000-metre rock blocks, each of which .can lead to millions of casualties. In 2006, the United States Congress to extend the mandate of the NASA, it must now monitor and catalog diameter more than 140 metres near Earth asteroid, tasks to be completed in the year 2020, the number of asteroids .in more than 2 million. <p> <wbr> </ p>.