A diameter of about 140 metres, codenamed “2011AG5″ near small objects (NEO) February 2040 may be passing near the Earth, its chances of collision with the Earth is approximately one-six hundred and twenty fifth. In early February of this year in Austria Vienna, the United Nations Committee on the peaceful uses of outer space (COPUOS) group meeting of science and technology, how to take effective measures to prevent the near small objects hit the Earth as scientists hot on the topic.
United States the Discover magazine once voted “threats to human survival in 21st century 20 great danger”, where small objects hit the Earth in the first place.
United States foreign policy magazine has listed “five kinds of situations which may lead to the end of the world”, near to small objects hit the Earth in the first place.
Shi in the determination of the United Nations “world’s four emergency disaster”, near to small objects hit the Earth was ranked first.
Visible near small objects of potential threats to Earth.
Famous scholar Professor Zhou Haizhong has repeatedly been invited to participate in the International Symposium on the collision of celestial bodies. A few days ago, China invited invite professors to do a interview in popular science on small celestial bodies threatens the Earth. According to Dr Yang Jianhua interview recording and arrangement are as follows:
China: what is near to small objects? It is said that they had collided with the Earth, and cause trauma to the Earth. Some of you talk about this situation.
Zhou Haizhong: small objects are those at or near the Earth’s orbit and the Earth’s orbit intersects the small objects, such as near-Earth asteroids, near-Earth comets (commonly known as the comets).
According to expert estimates, about 2000 of the solar system near small objects larger than 1 km in diameter and the nearly 100,000 greater than 100 meters in diameter and small objects. Near-Earth objects like that whether it hit land, was also hit the ocean, is going to be a global catastrophe of mankind cannot afford to ignore the risks of. Not long ago, the United Kingdom famous theoretical physicist Stephen Hawking in a media interview that: because of the threat of small celestial bodies, to suitable for survival of mankind must immigrate to other planets to get rid of the demise of fate.
So far from the formation of the Earth is 4.6 billion years. In the long months and years, there have been countless small objects hit the Earth. According to expert estimates, nearly 100 million years, the Earth was to small objects near the impact crater larger than 1 km in diameter, there are more than 10,000. Due to the protection of the Earth’s atmosphere, near the volume and quality of small objects tends to burn out even before the ground in the fall, or a small meteorite, meteor showers, and so on, but will cause ruin to the Earth.
Mainstream scientists believe about the end of the Cretaceous period 65 million years ago, about 10 km in diameter, the quality to 10 billion tons on the surface of the asteroid hit the Earth, which is now Mexico Northeast Yucatan coast. According to expert estimates, the impact released energy equivalent to 100 trillion tons of high explosive (TNT) exploded 5 billion times times the Hiroshima atomic bomb explosion, caused when the global climate, environment, and ecology of disaster, have been dominating the world of dinosaurs and many other species extinct.
On June 30, 1908 at 7 o’clock in the morning, a star diameter about 50 m of Comet in Russia Siberia pass ancient Republika card area over 5 km Department explosion, its destructive equivalent to 500 star Hiroshima atomic bomb, by produced of high temperature, and high pressure, and shock wave razed has square more than 2000 more square kilometers range within of about 60 million tree trees; this star Comet destroyed of is a no area, no caused more serious of social damage, this can said is lesser evil. 4 hours if it falls, St Petersburg will hit.
On April 22, 1989, a diameter of about 10 km of the “siweifute-Tuttle” comets sweep, and missed the time difference with the Earth for 10 days only because of its big, surprised many astronomers at that time out of the sweat. The periodic comets and walked past the Earth every 76 years, is a very dangerous “man”.
On November 8, 2009, a star diameter about 10 m, and run speed for each seconds 20 km of asteroid in Indonesia Su Laxi Island southern over of atmosphere in the explosion, issued detonation days loud, a section huge bent shaped dust cross had sky, caused large residents panic; this a explosion release out of energy has 3 star Hiroshima atomic bomb explosion of power; by fortunately of is, due to explosion of height in ground above 20 km around, so no caused any damage.
On November 9, a diameter of about 400 metres, codenamed “2005YU55″ asteroid with over 48,000 km per hour speed from the middle of the Earth and the Moon, with the closest for the 322,000 km of Earth; in the scale of the universe, which is very dangerous “close”. “Slip away” makes astronomers nervous throughout the world. “2005YU55″ is the first time in the last 35 years have similar sized asteroids so close to the Earth, the last time was in 1976, but astronomers do not know at the time that the fly sweep events until later notice. This cycle an asteroid within the next 100 years there will be several opportunities for closer contact with the Earth, 2,075 and approximately 240,000 km to nearest to the Earth.
Passing a to: near to small objects and Earth Zhijian distance has “cordon”, is 0.05 days text units, is 7.5 million km; Dang near to small objects crossed “cordon”, it on has may hit to Earth; if hit to Earth, it first to through near to space a is called “gravity keyhole” of regional, and is may in Earth gravity role Xia impact Earth; impact release of energy size depends on it of volume, and quality, and density, and structure features, and movement features, and flight speed, and impact angle, factors. Due to the effect of other celestial bodies, and the passage of time, close to small objects hit the Earth likely will change.
China: will not occur in the future, small body collided with the Earth?
Zhou Haizhong: according to historical records and scientific predictions, nearly collided with the Earth is the likelihood and severity of small celestial bodies; collision is just a matter of time, and will not issue. Unless human capacity in the future, there is a way to avoid “world collision” occurred, otherwise the consequences would be unthinkable.
According to expert estimates, 10 kilometers in diameter near the size of small objects around 100 million will collide with the Earth on average; approximately 1 km in diameter near the small celestial bodies is likely to hit the Earth every 100,000 years; approximately 100 meters in diameter near the small celestial bodies is likely to hit the Earth once every 10,000 years. Such impact will be to Earth with devastating effect. Even a small celestial body has not hit the earth near enough, just from us near the crossing, it would change the Earth’s orbit, so that humans suffer.
In June 2004, found that “abofeisi” asteroids are known to the greatest threat to small objects near the Earth, its diameter is about 400 metres; as soon as it hits the Earth, will release 100,000 times higher than Hiroshima atomic bomb of energy. According to expert estimates, it will be August 2029 walked past the Earth due to their orbits by the Earth’s gravity to change, it will restart in August 2036 “to” Earth, and Earth collision probability is 1/, in astronomy, which already belongs to the “very high probability”.
“Abofeisi” has been ranked the “Torre North grade” 4th grade, 10 means an inevitable collision of global destruction; it’s near small objects found on the danger of the highest level. If it crashed into a densely populated place, would have caused a major disaster to mankind; even if you hit the sparsely populated places, with serious damage to the local ecological. “Abofeisi” is the key monitoring object in the field of astronomy, at present there are more than 100 research working group is currently engaged in the study of dangerous asteroids, when you want it close to earth can reduce or exclude the possibility of a collision. In addition, the United States Space Agency, the European Space Agency and a number of related have jointly set up a 50,000-dollar bonus, collection tracking in the world “abofeisi” as well as the exact best way to detect its trajectory.
Scientists recently using software lists a copies in Earth suffered near to small objects impact of situation Xia loss most heavy of national of list, which part national will faced serious of personnel casualties, and also some national of Foundation facilities is will damage serious that cannot recovery power; listed of national including United States, and United Kingdom, and Sweden, and Japan, and India, and Brazil, and Philippines, and Canada, and Italy, and Nigeria and Indonesia, and China also is included which. In case of collision, the consequences for ranking countries, will be very intense. The main purpose of this list is to remind these countries prepare for disaster.
Fortunately is yet found on Earth in the near future pose a real threat to small objects, so people don’t have to be too concerned. In passing that “the 2012 ‘ effort than asteroids ‘ hit the Earth and destroy humanity” has no scientific basis, is purely rumor.
China: how to do a good job to prevent small objects hit the earth near? If found “killer” small objects, scientific organization which should be reported to the relevant situation?
Zhou Haizhong: first, should established a global of information, and analysis and warning system (only observation network is enough of), control world around of ground and space telescope to observation and track those may will to Earth brings disaster of near to small objects, this is prevent disaster occurs of Foundation; second, should developed a disaster risk of emergency plans, to do rainy day, before they happen; again, should equipped with more advanced of observation device, training more of senior specifically talent, while increased science publicity efforts. Finally, disaster preparation, disaster threat reduction.
Any organizations or individuals if “killer” small objects should be taken to the International Astronomical Union (IAU) report confirmation is verified, reported to the relevant departments of the United Nations by the International Astronomical Union; and to inform Member States of the United Nations, and global science and technology forces to take defensive measures.
China: the international community’s reaction to small objects near the threat? What is the action of the scientific community?
Zhou Haizhong: starting from the 90 ‘s of the last century, the international community, in particular the scientific community is very concerned about the possibility of small objects hit the Earth and risk issues. United States Science magazine has called on political leaders to give attention to this issue. Scientists are held almost every relevant international academic seminar to discuss measures for the resolution of the threat to small objects near Earth.
In April 1993, international scientists in Italy Miranda eeles convening a special international conference to discuss issues that may impact small objects, and issued a declaration of the Miranda eeles, trying to raise awareness on the issue of high priority. In July the same year, I was invited to participate in the Korea Seoul’s “mutant theory collided with the celestial bodies” international seminar, participants on the danger level near running mathematical model of small objects, the resulting energy, how to use equations to describe the collapse process of Exchange and discussion on issues such as.
Small near-Earth objects on the Earth’s threats have caused many countries attach great importance to. Current United States Space Agency, the European Space Agency, Russia space agency, Japan Aerospace Exploration Agency in strengthening that may endanger the planet near to closely monitor and track small objects, while seeking to avoid their impact solutions. In space, the Hubble telescope, wide-angle infrared measurement probes are continuously monitoring their activities. Located in United States, Hawaii island of Maori PS1 telescope (has the world’s largest digital camera, you can get a picture every 30 seconds) have also started the clock to search for traces of them; in Chile sailuopaken of LSST telescope will be put into use in 2014, at which time its search capability is PS1 telescope 24 times.
According to media reports, funded by the European Union, and Germany aerospace Project Center is mainly responsible for the defense of small celestial bodies “near-Earth orbit protection shield” is expected in the next 3-year assessment test, if funds are available, before 2020, will be formally implemented. Russia Planetary Protection Center that, if funding is essential to protect, Russia current technology all can be completed in 5 years small planetary protection system to protect the Earth from near-Earth objects of attack. United States is external space research most attention of national, for near to small objects will to Earth brings hurt of trends more is especially sensitive; under United States Congress 1998 of a items resolution, United States NASA started has name for “space guardian” of project, seeks to positioning earth around 90% above diameter does not is less than 1 km near to small objects of run track, and confirmed which near to small objects may will on earth caused threat. Chinese Academy of science in action, Purple Mountain Observatory, telescope time searching for and monitoring of the Beijing Astronomical Observatory and other units could break into the Earth’s “uninvited guests”, additional defense to small objects hit the earth near method of conceptual studies are also underway.
Although near to small objects hit the Earth is currently a small probability events, but to those at risk and destruction of the “invaders” is the need for a high degree of vigilance.
China: If you find that there is a potential threat to small objects near the Earth, what defence programme of the scientific community? Feasibility and reliability of the programme?
Zhou Haizhong: at present, the scientific community has a variety of defensive schemes, and some are ready to be put into action. “Theoretical feasibility” programme are:
Is using nuclear weapons to blow it, but the trouble is the explosion is likely to turn it into a number of small “killers”, unpredictable with a radioactive object into orbit, and some small loose structure of near-Earth objects, the role played by the explosion is very limited. This approach has been mixed.
Was the second spacecraft impacting it, change its orbit or breaking it. This comparison is valid, but as with nuclear weapons, it could expanded the disaster several times.
Three aircraft is to put pressure on it (that is, using mechanical force), speeding up or slowing down, thus changing the direction of its flight. This approach is ideal, but it is not easy to implement, and there is a certain amount of risk.
Four are surface using a laser material emanates, resulting in reverse acceleration to make it change the flight direction; or ultra intense laser to destroy it into small fragments of Earth-friendly. This method is also ideal, but have to have super high power laser systems.
Five are made of paints to change its color, effect it absorbs sunlight and heat, by changes in thermal energy to change its orbit. This method worked more slowly, also required a lot of paint delivered to is also a problem.
Six is a rocket sent to a giant kite-shaped solar sail above it, and opening rebound solar sail uses solar photon pressure gradually pushed it off the track. This method of high technical requirements, is quite difficult.
Seven is the insertion of a rocket-like device on the surface of it, let the device constantly emit substances, like jet planes, by reaction to change its direction of flight. This method seems a bit romantic.
Of course, there are other defensive scheme. However, all stage programmes now remain in the theory of ideas; whether they are practical and reliable, also depends on the future practice of testing.
[The respondents introduction]
Zhou Haizhong: 1983 graduated from the Guangdong University of foreign studies, current Professor of Sun Yat-sen University, Stanford Institute for forecasting consultancy. In addition to teaching mathematics, linguistics, cross-frontier scientific research work in the areas of science,. 1988-awarded the first ten outstanding youth of Guangzhou, Guangdong provincial people’s Government issued certificate of meritorious service in the same year, 2nd in 1990, Fok Ying Tung Education Foundation of young teachers in colleges and universities in China (research) award, 1992 enjoy the State Council issued special Government allowances.