3.8 billion years ago, primitive life was born on a beautiful blue planet in the habitable zone of the solar system, which is the earth. After billions of years of long evolution, life on earth finally gave birth to intelligent human beings millions of years ago.
In the life span of 3.8 billion years, the road of life evolution is not smooth sailing, but has experienced countless frustrations and disasters, including five mass extinctions and many small extinctions. Every extinction is a great renewal of life. Old life disappears and new life is born.
Throughout the earth’s 3.8 billion years of long life history, no creature can span endless years and continue to the present. The beginning of every era of life also means that it will come to an end in the future and be replaced by a new era of life. 300 million years ago, the earth was an era of giant insects. There are huge insects everywhere, and insects dominate the earth.
After the end of the giant insect era, the age of dinosaurs came. Another 160 million years later, 65 million years ago, an asteroid hit the earth, driving dinosaurs from the earth’s throne. After the extinction of dinosaurs, there was the rise of mammals and the birth of human beings millions of years ago. So, in a sense, the birth of mankind is thanks to the asteroid 65 million years ago.
Human beings have replaced dinosaurs and become the overlord of the new life era. The life era of human beings is different from other life eras, because we are intelligent life. Relying on wisdom, we become the new masters of the earth. Through wisdom, human beings embark on the road of scientific and technological development, walk out of the earth with the help of science and technology, and begin to explore the universe.
Although human beings are very great, through the law of life evolution and the law of entropy increase, no age of life can last forever. Sooner or later, the earth will also usher in the sixth mass extinction. In the new mass extinction of life, mankind, as the master of the earth, may not be spared, and will also embark on the same fate as dinosaurs. If human beings disappear, how can we prove that human beings once existed?
After the disappearance of human beings, and after a long period of evolution, there may be a new intelligent civilization on the earth. Can the new intelligent civilization know that human beings once existed? Maybe in the eyes of many people, time is a merciless knife, which can erase all traces of life. Thousands of years can turn a brilliant civilization into dust. If human beings disappear, after a long time, the traces of human existence may basically disappear. How can the new civilization prove that human beings once existed?
In fact, there are many ways to prove that an era of life once appeared. Especially for the scientific and technological civilization like human beings, even if it disappears for a long time, it will leave some traces. So what are the traces of human existence?
We study the life history of the earth mainly through the exploration of fossils, which is the most direct proof. The reason why human beings have a lot of knowledge about the life history of the earth is that scientists have found fossils of various life periods all over the world. Through these fossils, we can “travel through time and space” to understand part of the life history.
The glorious age of dinosaurs 65 million years ago was due to the discovery of a large number of dinosaur fossils around the world, so that scientists knew that before the birth of human beings, there was a glorious age of dinosaurs, which lasted for 160 million years. Under natural conditions, fossils can be preserved for more than you think. Theoretically, they can be preserved for billions of years. At present, the oldest fossil discovered on the earth is a microbial fossil, about 3.77 billion to 4.29 billion years ago.
If human extinction disappeared, then with the huge number of human population, there will be a large number of bone fossils, and these fossils will be sealed underground for hundreds of millions of years, there will be no problem at all. When the new civilization finds human fossils, then we can know that there was a brilliant human civilization on the earth.
2、 Electromagnetic wave
I believe we are not unfamiliar with electromagnetic waves. After entering the era of science and technology, the application of electromagnetic waves is more and more in-depth, especially in the past 100 years, the development of electromagnetic waves is changing with each passing day. The stronger the civilization is, the stronger the development of electromagnetic wave is. Electromagnetic wave is a kind of broad and powerful energy. When human beings enter the space age, a large number of electromagnetic wave signals spread from the earth to the universe.
The scientific and technological activities of human beings have formed a “radio layer” centered on the earth. Within this “radio layer”, wireless electromagnetic waves are constantly transmitting all the time. Even if human beings disappear, these wireless electromagnetic waves will exist in the universe for a long time. If a new civilization enters the era of science and technology, it is possible to receive these signals from human beings, so as to know that before them, another civilization has also embarked on the road of science and technology.
3、 Interstellar probe
In 1977, scientists launched Voyager 1 and Voyager 2 into the universe. They both carried a gold record of human information. The goal of Voyager spacecraft is to go all the way out of the solar system until it stops by accident. At the speed of Voyager 1, it will take tens of thousands of years to get out of the solar system and at least hundreds of thousands of years to reach the nearest star system.
After the disappearance of human beings, the interstellar probes launched by these scientists will not disappear and will continue to move forward in the universe. When the newly born civilization enters the space age and has the ability to walk out of the solar system, we may find these two detectors. We can know their origins through the gold records left on the detectors, and we will know that human beings once existed.
In addition to the above three kinds of human traces, there are other traces of human existence that can also be preserved for a long time, such as nuclear reactors. The decay cycle of uranium can reach hundreds of millions of years. As long as human beings have used nuclear reactors, the traces will not disappear even after hundreds of millions of years. As long as new civilizations discover these decaying uranium, they will be able to know the existence of human beings.
The more powerful human science and technology are, the more powerful the traces of civilization will be and the longer they will be preserved. Therefore, after the disappearance of human beings, it is difficult for years to completely erase all traces. There will be proof of human existence. That’s why many people deny the existence of prehistoric civilization. If a powerful prehistoric civilization really existed, how could it not leave any trace?
We can’t find any trace of the existence of prehistoric civilization. It can only show that without prehistoric civilization, human beings are the only intelligent civilization that has ever appeared on the earth. Although we know that the final outcome of human civilization will be the end and disappearance, human beings still have to strive for rapid development. Only when the strength of science and technology is strong enough to spread the pace to all corners of the universe, human civilization can last for a longer time.
If we have been shrinking on a small earth, it is too risky for human beings. Any disaster from the universe can easily erase human beings from the earth. Only when we go to the starry sky and put the eggs in different blueberries, will the survival ability of human civilization be stronger and last for a longer time.