This paper takes part in the series essay competition of “great science” of Recordunkown.
The earth was born 4.6 billion years ago. After more than 1 billion years of evolution, the earth finally became stable. At this time, the suitable ecological environment began to breed life. About 3.8 billion years ago, the early single cell life began to be born on the earth.
After the birth of simple life, and after a long period of evolution, life forms become more and more complex, with the later rich species, with the later birth of human. From the birth of life on earth to the birth of human beings, it has experienced billions of years of evolution and evolution, which shows how difficult the birth of human beings is.
In the evolutionary history of the whole life on the earth, it is not that the sails are not smooth. During this period, there have been five mass extinctions, each of which has wiped out most of the life on the earth. The reason for the mass extinction of these organisms is that the earth’s ecological environment has undergone great changes. These great changes may be the earth’s own environmental changes or plate movement. For example, when Pangea split, it triggered the fourth mass extinction.
In addition to the earth’s own reasons, the asteroid impact from space has also become an important reason for the earth’s ecological changes. Through geological survey, scientists have found ten major craters on the earth. These craters are still very magnificent. Through them, we can imagine how huge the meteorites that hit the earth at that time were.
So it is not sure whether the impact of these meteorites is related to the five mass extinctions. Through the detection of the crater, scientists only know that the time of the fifth mass extinction is basically the same as that of the chicxulubo crater, which is the second largest crater in the world, with a diameter of 150 kilometers. Many scientists speculate that the dinosaur mass extinction event 66 million years ago was caused by the impact of a huge asteroid.
Although the other four mass extinctions did not exactly coincide with the appearance of the top ten craters, we do not completely rule out that there is no connection between them. We should know that after a huge asteroid impacts the earth, sometimes it can’t bring the mass extinction to the earth immediately. What’s more, a huge impact will bring a series of side effects, such as crustal movement, volcanic eruption and so on.
These follow-up effects may cause great changes in the earth’s ecological environment, leading to subsequent mass extinctions. Scientists have found a rule through the time interval of five mass extinctions. It seems that mass extinctions occur every tens of millions of years on average, and the time interval between the ten major craters on the earth also shows a certain regularity.
If the impact of asteroids, mass extinctions on the Earth presents a periodic appearance, then the earth may also usher in the sixth and seventh mass extinctions in the future. If the earth ushers in the sixth mass extinction event in the future, can mankind escape?
Before the emergence of human beings, once there is a huge ecological disaster, creatures can only passively accept the fate of destruction. For example, in the age of dinosaurs 66 million years ago, although dinosaurs were the overlord at that time, they only relied on brute force to achieve the status of overlord. Once they encountered natural disasters or other huge disasters, they could only face the fate of extinction.
But since the birth of mankind millions of years ago, after millions of years of development, we have entered the era of science and technology. However, the powerful power of science and technology is likely to change many things. Can mankind survive the sixth mass extinction by relying on the power of science and technology? To know the answer, we need to analyze the possible causes of the sixth mass extinction.
As we have said above, there are only two reasons for mass extinction: one is the great changes in the environment of the earth itself, and the other is the threat from space, mainly asteroid impact.
Under normal circumstances, the structure of the earth is very stable. Although the movement of some plates often causes some earthquakes, it can not cause huge changes of the whole plate. It is estimated that the great changes like the Pangea breakup more than 200 million years ago will not happen in the future. Therefore, we don’t need to consider that the global huge movement of the earth plate will cause the mass extinction.
Of course, there is another situation of great changes in the ecological environment, that is, great changes in the climate, such as the rising global temperature, which will eventually lead to a series of huge disasters, and may also bring about mass extinction of organisms. However, this is a long time. Human beings have enough time to remedy and respond, and it will not pose much threat to human beings.
In fact, asteroid impact is likely to pose a great threat to human beings. Although mankind has entered the era of science and technology, and also began to explore space, but in the face of asteroid impact, we still have no good way to intercept and respond.
Someone may have seen some disaster movies, in which scientists use nuclear bombs to blow up asteroids and remove the threat to the earth. So can the nuclear bomb, the most powerful weapon of mankind, intercept asteroids? In fact, it is very difficult. If some small asteroids enter the earth orbit, they can be intercepted by nuclear bombs. But if it’s some giant asteroids, there’s nothing we can do about it.
For example, the diameter of each of the top ten craters on the earth is more than tens of kilometers. If such a huge asteroid collides with the earth, the only hope is that it will be intercepted before it enters the earth orbit. However, with the current space technology of human beings, there is little hope of successful interception. Even if a nuclear bomb successfully hits a huge asteroid, it will be very difficult It’s hard to do any damage to asteroids.
Once a huge asteroid enters Earth orbit, there is no possibility of successful interception. Moreover, the time from asteroid impact to earth impact is very short. Even if it is detected in advance, it may only take a few months. In a few months, we can’t think of a good way to deal with it. The only thing we can be sure of is the area where it hit, and then evacuate people there.
However, if the diameter of the asteroid reaches more than 30 km, it is useless even if people are evacuated, because once such a huge asteroid hits the land, a series of effects will lead to the sixth mass extinction of the earth, and the probability that human science and technology can survive is very small. If it’s an asteroid with a diameter of more than 100 kilometers, we don’t have any expectations. It will completely destroy all living things on the earth and may directly turn the earth into a barren planet like Mars.
Thus, asteroid impact is the greatest threat to human beings. Although this probability is very small, according to scientists’ research on the top ten craters, it seems that there is a certain periodicity in the impact of a giant asteroid on the earth, which may be related to the rotation of the sun. If so, the earth may encounter the impact of a huge asteroid in the future.
If human beings want to survive in the future, they can only rely on science and technology. As long as the power of science and technology is strong enough, we can intercept asteroids of any level, so that they can not threaten the survival of the earth and human beings. In this way, we can effectively avoid the mass extinction caused by asteroid impact.
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