I believe that people who know a little about the history and military will not be unfamiliar with the power of nuclear weapons, and the Second World War, a war that caused great harm to all mankind, ended with the two atomic bombs dropped by the United States in Japan. If there had been no two atomic bombs at that time, the end of the war might have been postponed, and the power of the atomic bomb itself shook the world.
Never before in human history has a weapon capable of completely destroying a city in such a short period of time that would cause enormous harm to all traces of civilization and to life itself. As a result, people have since become more cautious about the use of nuclear weapons, and only a few countries have been able to legally possess nuclear weapons so far.
China is also one of the legitimate nuclear powers, but we will never easily use such a powerful weapon, because we know that once a nuclear war occurs, no country will be able to retreat completely, and even the entire human civilization will be destroyed. Obviously, we cannot yet imagine what kind of fate humanity will face when more powerful objects descend upon this world.
In fact, such a thing did not happen on the earth, but at that time, human beings had not yet appeared, and the "master" of the earth's biosphere was not a human being, but another animal that we are familiar with and unfamiliar with - dinosaurs. It is said to be familiar because we can see dinosaur fossils and introductions everywhere, and strange because none of us have ever seen a really living dinosaur.
< h1 class= "pgc-h-arrow-right" > terrifying asteroid impact</h1>
75 million years ago, when the Earth was a world full of dense plants, the absolute advantage in nature was a creature called dinosaurs, which belonged to the reptile category, with many different varieties. Although dinosaurs did not create their own civilization, they firmly "suppressed" other types of organisms such as mammals.
But on a seemingly ordinary day, an asteroid with a diameter of ten kilometers fell to the earth, causing an unprecedented huge explosion. But that's not the end of it, the dust and debris stirred up by the asteroid explosion entered the atmosphere, blocking the sunlight, and the Earth's climate changed drastically after that, and most of the world's organisms went extinct in this asteroid impact event.
Dinosaurs are no exception. The scientific community believes that this asteroid impact is one of the most important reasons for the overall extinction of the dinosaurs, and the mammals and other small creatures that "sneaked up" in the great catastrophe eventually became the masters of the earth in the following days, including our ancestors.
From the objective result, human beings must also "thank" the asteroid, otherwise the people living on the earth now may still be "fearful". Some people wonder: why can an asteroid with a diameter of ten kilometers be less than the size of a city cause the result of a global mass extinction on Earth? In fact, we may have greatly underestimated the power of meteorite falls.
< h1 class="pgc-h-arrow-right" > why is the meteorite falling so powerful? </h1>
Earth is a planet that orbits the sun regularly, and the other major planets in the solar system have their own trajectories, and everyone does not disturb each other. However, there are also many less "disciplined" objects in the universe, which are captured by the gravitational pull of other celestial bodies in the process of traveling, resulting in impacts, so the planets are often "scarred".
Earth is no exception, relying on its own gravity to attract a large number of tiny stars, but we do not see meteorites falling on the earth all the time, that is because the earth has the protection of the atmosphere. Most stars are so small that they burn out in the atmosphere due to frictional heat, so we rarely see meteorites fall.
In addition to the atmosphere, the Moon is one of the reasons why we are less exposed to direct impacts from celestial bodies. Today we can see that the moon is full of craters, in fact, a large part of them are directly hit by the earth, and the moon is worthy of our "satellite".
Of course, even with the addition of "double insurance", there are still some meteorites that will land on the earth, and the reason why they are so powerful is because unlike the general impact, meteorites will explode when they fall, and the shock wave generated is comparable to nuclear fission. Therefore, we generally do not see meteorites in "craters", and most of the meteorites we can collect on the market are fragments after the explosion.
<h1 class="pgc-h-arrow-right" > Why do meteorites explode when they land? </h1>
After analyzing many meteorites, we will find that the main component of most meteorites is silicates, and some of them also contain other minerals, such as iron ore, copper ore, gold ore and so on. But in general, these minerals are basically found on the earth, and the chemical properties are very stable, simply speaking, it is just a stone.
So why does an ordinary stone fall from a high altitude and explode like a nuclear bomb? How does it work? This starts with the "energy" of the meteorite itself. The explosion itself is a process of releasing a huge amount of energy in a very short period of time, and its essence is the transformation of one or several energies into another.
Meteorites enter the Earth from the atmosphere, and the acceleration of gravity allows the meteorites themselves to carry a large amount of kinetic energy, which will burst out instantaneously when they hit the ground. The stone we usually see does not explode when it falls to the ground, because the kinetic energy it carries is not enough, and the speed of the meteorite can reach tens of kilometers per second during the landing process, so the kinetic energy is naturally terrible.
At the time of impact, the internal energy and potential energy contained in the meteorite itself will explode, not only will the meteorite and the objects on the ground become fragments due to the strong impact, but also release extremely amazing thermal energy at that moment, so the meteorite we see landing on the ground is as amazing as the explosion of a nuclear bomb.
So some people may ask, is the energy of the meteorite explosion comparable to the power of a nuclear bomb? The answer is that large meteorites are much more terrifying than nuclear bombs. We assume that the meteorite falls at a rate of 50 kilometers per second, so the energy produced by a one kilogram meteorite is equivalent to a 300-ton explosive explosion.
If we compare this unit with the asteroid that destroyed the dinosaurs, we conclude that it is equivalent to 10 billion atomic bombs that exploded in Hiroshima. Just one atomic bomb can destroy a city, and 10 billion atomic bombs can completely destroy Earth's civilization.
< h1 class = "pgc-h-arrow-right" > the outcome of a meteorite</h1>
Of course, there are also some meteorites that do not explode because of the potential energy hitting the ground, and some meteorites begin to burn and explode in mid-air, which is also because the meteorites accumulate enough energy during flight, such as compressing the air in front of them, so that they explode before landing. So, what does a meteorite become after it hits the ground and explodes?
The Earth has been formed for 4.6 billion years, and there should be a lot of meteorites that have landed on the Earth, so why are we able to find very few now, and most of them are meteorites that landed relatively late? In fact, many of the composition of meteorites are also familiar minerals, which gradually merge with the surface after landing on the ground, and gradually disappear in the process of geological changes.
Meteorites themselves form part of the Earth. There was no atmosphere or ocean on the primordial Earth, and at that time there were many meteorites that landed on the Earth, and these meteorites brought moisture to the Earth, and later they were able to combine with the water originally contained in the Earth's interior to form a primitive ocean, and gradually formed an atmosphere rich in water vapor.
In addition to water resources, many minerals on the earth are also brought by meteorites, and some researchers believe that the gold on the earth is "alien visitors", which is not unreasonable, because humans have repeatedly discovered gold meteorites known as "dog head gold".
<h1 class="pgc-h-arrow-right" > how do humans face meteorite impacts? </h1>
As the saying goes, "there's an unexpected storm in the sky," and people studying paleontology that have disappeared, or meteorites, might wonder what would happen if we had another asteroid impact like the one 75 million years ago. Is there a way for humans to resist?
The first thing to understand is that we don't have to sit at home now to "worry about the sky", because the current astronomical observation technology is already very developed, and our scientists can't wait until the asteroids have fallen like dinosaurs. Previously, a celestial body called "Oumuamua" had broken into the solar system, and although it was far from Earth, we still monitored it throughout the process.
Even if we find an approaching asteroid, we can inform people in advance for evacuation and preparation, such as building an underground city and so on. While asteroids may wipe out the vast majority of life, this process does not happen instantaneously, but gradually over the next few million years as the Earth's overall climate changes.
In such a long time, human beings have been able to develop their own technological level to a higher level, and may already be able to collectively take refuge in aliens, so we don't need to start panicting now.
< h1 class="pgc-h-arrow-right" > concluding remarks</h1>
Although human life is indeed fragile, we should not underestimate the viability of our own race. In the great catastrophe of the disappearance of such powerful creatures as dinosaurs, our mammalian ancestors have also stubbornly survived, not to mention the present that has evolved for so many years and has created civilization?
I believe that even if such a thing really happens, the tenacity and unity of mankind will certainly be able to overcome many difficulties, continue to continue our race, and eventually move towards a broader cosmic space full of opportunities and challenges. That is why we should continue to develop our science and technology and strive to take more initiative in the face of nature.
Of course, in addition to the need to continue to develop our technology, it is also a very important point not to "kill each other". We may not be wiped out by asteroids, but our civilization could be destroyed by nuclear war. Once the relationship between people and people, nations and nations falls apart, it is only we who will ultimately suffer the catastrophic outcome.
Someone once said that "the third world war was a nuclear war, and the fourth world war can only use stones and wooden sticks", which is exactly the truth. Therefore, we must also cherish the hard-won peace in which we live.