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A Russian scientist predicts that one day in 2036, an asteroid will hit the earth, and the energy generated by its explosion is equivalent to 1 10000 atomic bombs exploding in Hiroshima, and life on earth will be destroyed.
According to the Russian newspaper Izvestia, at the symposium on the safety of asteroids and comets held in St. Petersburg, Russia on October 3, 65438, Russian astronomer Shor announced his conclusion that this asteroid named Apophis will hit the earth in 2036.
According to Shore's calculation, in 2029, after asteroids pass the earth at an altitude of more than 30,000 kilometers from the earth's surface, their own state and orbit will change due to the gravity of the earth. This change is enough to cause it to "hit" the earth six years later, in 2036.
Apophis has a diameter of about 320 meters and a mass of about 42 million tons. When approaching the earth, it runs at a speed of 5.9 kilometers per second. If it hits the earth, it will generate energy equivalent to 1 10000 Hiroshima atomic bombs.
According to the model made by Shore, if Apophis hits the Pacific Ocean, it will set off a 200-meter-high wave, and the dust raised by its shock wave will cover the 1/4 area of the earth, and the animals, plants and humans in this area will die because of the cold and the destruction of the food chain. ...
Expert interview
The impact is inevitable, and mankind is ready.
Will Shore's prediction come true? Our reporter interviewed Dr. Zhu Jin, curator of Beijing Planetarium.
Zhu Jin said that at present, scientists in China have not got the exact data of whether the Apophis asteroid will hit the Earth, but it is only a matter of time before a similar impact event is inevitable. At present, among the more than 300,000 asteroids in the solar system, the probability that more than 70 asteroids will hit the Earth in the next 100 year is "greater than zero".
An asteroid with a diameter of 1 km will directly kill the global population of14; Asteroids with a diameter of more than 20 kilometers are enough to make 90% of the species on the earth completely extinct. Apophis is only 320 meters in diameter. If you hit the earth, it will not cause the complete extinction of mankind, but the consequences will be "very serious."
However, human beings have come up with many ways to prevent asteroids from colliding with the earth. Among them, the most classic and exciting method is "blasting method", that is, launching missiles or filling explosives at celestial bodies that threaten the earth and blowing them into pieces, so that the pieces deviate from the original orbit. Of course, this method can only be used to deal with rocky celestial bodies, and the use of nuclear weapons in space may also bring very serious consequences to the earth.
Some scientists suggest that spacecraft can "walk side by side" with asteroids at the same speed and direction. When they are relatively static, the mechanical arm can be used to "push" and change its orbit.
Others proposed to place a "giant rocket driver" on an asteroid to change its orbit; Or put a huge condenser in space to reflect sunlight and evaporate asteroids.
Although some of these whimsy are only conceptual schemes, with the development of science and technology, human beings should be able to find ways to avoid the disaster on the earth.
Background link
Naughty asteroids give scientists a headache.
"Turin Collision Risk Grade" is a standard used by the astronomical community to evaluate the collision probability of "whisperd" with the Earth, and it is divided into 10 grades. Most of the "naughty" asteroids are only 8 or 9, and the probability is only a few ten thousandths. However, this probability is enough to make scientists have a headache. It is necessary to determine or rule out the possibility of "kissing" the earth through repeated observation and calculation.
In July, 2002, Russian astronomers announced that an asteroid would collide with the Earth in February, 20 19, and the probability of hitting the ground was as high as 1/9000. However, within a few days, scientists completely ruled out the possibility of hitting the ground.
In September 2003, American astronomers warned that an asteroid with a diameter of 1 km and a mass of 2.6 billion tons was flying towards the earth, and its probability of hitting the ground was about1/900,000. After further calculation by scientists, the possibility of it hitting the ground was finally ruled out.
Will asteroids really hit the earth?
Will asteroids really hit the earth?
From the photos of the earth taken by satellite, we can clearly see a strange circular crater, the most representative of which is the "Balinger Crater" with a diameter of1.250m in Arizona, USA. People have always speculated that this pit is the result of meteorite collision. At the beginning of the 20th century, an American engineer, barringer, made a lot of arduous explorations around the pit, drilling to a depth of 400 meters, but never found any trace of the supposed meteorite. In memory of him, the American Meteorological Society named this crater "Balinger Crater".
Why didn't the "Balinger Crater" leave traces of meteorites? As we all know, meteors can burn out completely when they pass through the atmosphere. But the main components of large meteorites are silicon and iron. Once they land, they will gradually cool down and will not continue to burn. It is hard to imagine that a meteorite that smashed a huge pit of thousands of square meters would evaporate and disappear. Logically speaking, the quality of meteorites should be proportional to the diameter and depth of craters, and various meteorites can be found in craters formed by meteorite impact, which has been verified by a large number of facts. For example, after 1967 in meteorite shower, Jilin Province, a stone meteorite of 1770 kg was found in a pit with a diameter of only 6 meters.
To explore the origin of this circular crater, we should start with the evolution of the earth. Because of the thermonuclear reaction in the earth, the energy keeps accumulating, and when the earth's crust can't bear the pressure, lava erupts. When the magma cools and solidifies, with the support of water and steam mixed in the magma, cavities will be formed in the rock stratum (just like bubbles left when firing glass). Because some caves are shallow from the surface for a long time, the water and steam in the caves will be lost along the cracks in the rock strata, and the top of the caves will collapse without internal pressure support, forming a sunken annular pit. Because this kind of pit is formed by the collapse of molten cave, the inner wall is steep, even in the shape of an urn with a small mouth and a big bottom. Like Qixiping Giant Pit in Shennongjia, Hubei, China, the diameter of the pit mouth is about 4 10/0m, and the diameter of the pit bottom is about 530m. On the edge of the pit above the pit, there are two stones left by the collapse of the molten hole.
As for the slightly higher lip around "Balinje Crater", it is because this molten cave is a dome, which expanded to the ground before it collapsed, and the lip is the residual edge after the dome collapsed. At present, there are many such ground domes in the western United States, where the underground is a molten hole. This kind of giant pit and molten cave are two forms of a geological structure in different periods, and their formation reasons are closely related to the geological evolution inside celestial bodies, and they also exist on other planets. So it is understandable that barringer can't find meteorites here.
The collision of celestial bodies in the universe is frequent and common, but it is also conditional. There are countless asteroids around the earth, and a collision with any one of them will bring disaster. However, the premise of celestial collision is that there must be a very large mass gap between two celestial bodies, so that the gravity and centrifugal force between celestial bodies can be out of balance and collide. Although humans have not yet calculated the exact value of the mass gap between celestial bodies, the earth can only attract celestial bodies with a mass of less than one trillion. Therefore, in theory, there is no possibility that a massive celestial body will hit the earth, and it has never happened in reality. The largest meteorite found on the earth is a 60-ton iron meteorite in Namibia, Africa. Even the impact of comet 1994 only left a dark spot in Jupiter's dense atmosphere and had no substantial impact on Jupiter.
Since the historical records of mankind, those frequent "whispers" have not and will not bring any great harm to the future earth, so there is no need to worry about it.
Author: Kenichi
Excerpted from the book Changes in Natural Matter-Revealing the Mysteries of Life, the Earth and the Universe.
Will an asteroid hit the earth?
[Jane 1] was released on June 0113: 43: 04, 2006.
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Will an asteroid hit the earth?
The absurd story that the earth was hit by an asteroid and human civilization was instantly destroyed was once a common content in many science fiction works. 1994 The astronomical spectacle of "comet hitting wood" and repeated meteor showers caused some concerns. "Asteroids hitting the earth" seems to be a very realistic and serious problem. In addition to the above phenomenon, there is another important factor that worries about the threat of celestial bodies from outer space, that is, the "crater" on the earth's surface.
Among these craters, the most representative one is the hemispherical crater located in Arizona, USA, with a diameter of about1.240m and an average depth of1.80m.. Many scientists believe that this crater is a crater caused by the impact of a huge iron meteorite. At the beginning of the 20th century, barringer, an American mining engineer, took a keen interest in this circular crater, so he used huge financial resources to drill in the crater, but he didn't find the mysterious iron meteorite that seemed to be hidden except the layers of broken debris. Finally, barringer's efforts had to end in failure. Mining in barringer is not successful, but it is undoubtedly meaningful in scientific research. In recognition of his achievements, the American Meteorological Society named this crater "Balinger Crater".
Why is there no trace of meteorites in "Balinje Crater"? We know that the atmosphere is the earth's thick "body armor". Most small meteorites burn up in the air because of the high temperature caused by friction when they don't reach the earth's surface. The dazzling meteors are the remnants of their lives. Large meteorites (mainly composed of silicon and iron) can fall from the sky through the atmosphere, but they will gradually cool down and stop burning after landing. Usually, the quality of meteorites is directly proportional to the diameter and depth of craters. Generally, all kinds of meteorites can be found in craters formed by meteorite impact, which has been verified by a large number of facts. For example, in 1976, a meteorite weighing 1770 kg was found in a crater with a diameter of only 6 meters in meteorite shower. It is hard to imagine that an iron meteorite will burn and disappear without a trace when it hits a huge crater of several hundred square meters. It can be concluded that "Balinger Crater" is not a meteorite impact crater.
To explore the cause of the "Balinje Crater", we should start with the change of the crust. Lava erupts when the earth's crust can't bear the pressure accumulated by the energy generated by the nuclear reaction inside the earth. After the Big Bang at the end of Cretaceous, numerous mountain canyons and a large number of lava caves were formed on the earth's surface. A molten cave is a cavity formed in a solidified rock layer due to the support of water vapor wrapped in magma (like bubbles left in products when firing glass), in which the surface magma solidifies to form a shell first, and a large amount of water vapor is enclosed in the rock layer. Lava caves are located in the mountains on the surface of the earth, and there are also twists and turns hidden deep underground. Just like the picturesque mountain peaks in Yamazaki, southwest of China, there are caves in every mountain. People walk in the underground maze built by lava, and can't help sighing at the ingenuity of nature.
In some areas where the surface rocks are limestone and sandstone, some underground lava caves are very shallow from the surface. After a long geological age, the water and steam in the cave lost along the cracks in the rock, and the top of the cave collapsed without internal pressure support, thus forming various surface depressions. The formation of "Bahrain Street Crater" is a loose limestone and sandstone structure, and the unique geographical environment makes this giant crater unique.
It has been noticed that the thick limestone and sandstone layers around the "Balinger Crater", which constitutes the stone wall, were broken by a terrible force and turned outwards. Some rocks at the bottom of the pit have broken marks caused by violent impact, and stone walls, stone walls and the bottom of the pit are covered with stone particles, all of which show the characteristics of rock collapse. Because the top of the molten cave before the collapse was a dome rising to the ground, an annular pit lip with a height of 30 meters around the pit edge was formed at the edge of the dome left after the roof collapsed.
Because this kind of giant pit is formed by the collapse of lava caves, the inner walls are mostly steep, and some even take the shape of an urn with a small mouth and a big bottom. Like the "sinkhole" in Qixiping, Qiyan Peak, Shennongjia, Hubei Province, China, the diameter of the pit mouth is about 4 10 meter, and the diameter of the pit bottom is about 500 meters. There is a 5-meter-long stone strip named "Eagle Mouth Stone" on the west edge of the crater (it should be hung above the crater when the molten cave collapses). Looking down from the stone bar, the bottom of the pit is a lush thousand-year-old tree, and the intermittent fountain is crystal clear. In the rolling mountains of leye county, Guangxi, there is also the world's largest "Tiankeng" group, which, like a huge funnel, is densely arranged within more than 20 kilometers of Fiona Fang. There are holes in the pit, which are connected with each other, showing the magical essence of the violent activity of lava to human beings.
This crater and underground lava cave are two different forms of the same geological structure, and their formation is closely related to lava activity in the crust and has nothing to do with meteorite impact. Not only on the earth, but also on other later planets. When you look at the moon through a telescope, the first thing you see is a crater, surrounded by dense mountains and with depressions inside. Although the structure of the crater is not consistent, it basically has the characteristics of concentric circles similar to the crater, and even more circular craters with flat bottoms are exactly the same as the "Balinger Crater". Such unusual planetary forms (such as Mercury and Venus). And pits on asteroids) all originated from the same reasons as craters and craters on the earth.
When the planet experienced an early continuous shell explosion. As the crust thickens, the internal pressure decreases, and the degree of eruption weakens, the lava is not enough to accumulate into a towering cone-shaped fire peak, so the low craters and craters are all over the planet in the later period. Of course, not all craters on the earth are formed by the collapse of molten caves. But most of them are pits formed by the direct collapse of the eruption center when lava erupts. Because of the different internal pressure, rock thickness and magma composition, the shape of the annular pit is also different.
Collisions between celestial bodies in the universe are frequent and common, as evidenced by meteors in the night sky (tens of thousands of meteorites fall on the earth every year). There are countless asteroids shuttling around the earth, but the celestial bodies are regular, not arbitrary. The premise of celestial collision is that two celestial bodies must have a very large mass gap and a very close distance, so that the gravity and centrifugal force between celestial bodies can be out of balance and collide. If the mass of the Earth and the asteroid are not much different, because their magnetic fields repel each other, they can keep a relative distance, and even if they cross the Earth's orbit, they will not collide.
At present, humans can't calculate the exact proportion of the mass gap between celestial bodies. The largest meteorite found on the earth so far is the 60-ton "Hoba" meteorite from Namibia, Africa. From this calculation, a celestial body as big as the earth can attract 1 trillion or less celestial bodies equivalent to the weight of the earth's 6 trillion tons. Therefore, in theory, there is no possibility of a relatively massive celestial body hitting the earth, and in reality, there has never been an example of a meteorite hitting the earth causing a serious disaster.
1In July, 1994, the striking comet Shoemaker-Levi 9 flew to Jupiter at a speed of 60 kilometers per second, and 2 1 comet nuclei landed on Jupiter one after another. The diameter of fireballs produced by the magnificent "collision of comets with trees" was 10 kilometers. However, such a huge explosion only formed a dark black dust cloud at the top of Jupiter's dense atmosphere, and did not have any substantial impact on Jupiter's structure and operation. The mass of Jupiter is 365,438+07.89 times that of the Earth, and the energy and gravity of the Earth cannot be compared with that of the giant Jupiter. Jupiter can attract much more objects than the earth, and the objects that hit the earth and Jupiter are completely different in mass. Therefore, an object that can land on Jupiter does not mean that it will land on the earth.
Since ancient times, it is not "space rocks" from outer space that pose a direct threat to the earth, but frequent volcanic eruptions and earthquake disasters. These disasters destroy cities and devour life because of crustal changes. The subjective prediction that asteroid impact will bring disaster to human beings is exaggerated and has no objective factual basis.
Kenichi
Excerpted from the book Changes in Natural Matter-Revealing the Mysteries of Life, the Earth and the Universe.
It is available in the online bookstore of Beijing Book Building.