Today’s earth has only one intelligent civilization, humans, but the earth has a long life history of 4 billion years. In such a long time, is there really only one civilization of human beings on the earth? We must know that human beings have evolved from the ancient apes to the present, and it has only been a few million years.
Millions of time have created today’s human science and technology civilization, so the life history of 4 billion is thousands of times the time of human evolution. If there is a cycle of civilization every hundreds of millions of years, there may be more than ten civilizations that have appeared on the earth. Of course, this is just a kind of wild conjecture of ours, whether prehistoric civilization ever existed, there is no definite trace to prove it.
And after human beings walked out of the earth, from the perspective of the vastness and time of the universe, there should be many interstellar civilizations that are much stronger than human beings. The universe should be very lively, but the real result is that we see a quiet The lonely space of the universe.
Since there is a high probability that there are many intelligent civilizations in the universe, which are very lively, why is it so lonely now? Some people speculate that the past universe may indeed be very lively, there are many intelligent civilizations, but these intelligent civilizations have been extinct and disappeared in various disasters.
If the alien civilizations in the universe cannot develop forever, they will become extinct and disappear in the process of civilization, then humans may also have such a day in the future. So a friend raised the question: If humanity disappears from extinction one day, will the newly born civilization know that humanity once existed?
Countless years after the extinction of mankind, a new intelligent civilization has appeared on the earth. In the eyes of the new intelligent civilization, we are prehistoric civilization. Can they know that humans once existed? Perhaps the new wisdom civilization will also speculate that other wisdom civilizations may have appeared based on the long life history of the earth billions of years.
How can we prove that humans once existed? At this time, it is necessary to look for all traces of human existence. Some people may say that years are a ruthless knife that will erase all traces of human existence. Is this really the case?
Time can erase the traces of civilization. There is nothing wrong with it, and as time goes by, it will erase the cleaner. However, no matter how strong the years are, for a human civilization that has entered the age of science and technology, it will not be able to completely erase the traces of science and technology. There will always be some clues.
If human civilization disappeared before it entered the technological age, then hundreds of millions of years later, there may really be nothing left, and all traces will be erased. However, human beings have embarked on the path of scientific development hundreds of years ago, and the emergence of technology will make many things extraordinary.
If a new intelligent civilization is born after tens of millions of years after the disappearance of human beings, the traces of human existence will be easy to find. We all know that 65 million years ago, before the birth of mankind, there also existed a glorious era of hegemony. At that time, it was the dinosaurs who dominated the earth as tall creatures. They were found in every corner of the earth, and the number of races was very large, accounting for more than 80% of the earth’s creatures at that time.
Later, an asteroid with a diameter of 10 kilometers hit the earth, triggering a drastic ecological change, which caused the dinosaurs to become extinct and disappear on the earth. Now that 65 million years have passed, scientists have discovered a large number of dinosaur fossils all over the world before they know the glorious age of dinosaurs.
In 65 million years, although the years have erased the traces of a large number of dinosaurs, those fossils cannot be erased. Scientists have seen the prosperity of dinosaurs at that time through dinosaur fossils. In the same way, human beings are now the overlord of the earth, they are spread all over the world, and their numbers are also very large.
If humans disappeared due to a disaster, then tens of millions of years later, human fossils can be preserved. And the newly born intelligent civilization, through these human fossils, you will know that before they appeared, there was a glorious human civilization on the earth.
But what if the emergence of a new intelligent civilization is hundreds of millions of years later? Will there be traces of human existence? If the time span reaches hundreds of millions of years, the fossil traces of human existence may also be erased by the years. Even if they are left, they are likely to be in the depths of the earth and are not easy to be discovered by new civilizations.
If the time reaches hundreds of millions of years, then the traces that can prove that humans have existed on the earth may only be nuclear reactors. We all know that the most powerful energy source for human science and technology is nuclear energy, and the raw material of nuclear energy is uranium. As long as we use a substance like uranium, it will leave a long trace.
The reason is that the half-life of uranium is very long, basically over hundreds of millions of years. Scientists in Africa once also discovered a natural nuclear reactor. At that time, scientists mistakenly thought that it was evidence that a prehistoric civilization existed, but later studies found that it was a naturally formed nuclear reactor that had existed for 2 billion years.
Scientists were able to discover this natural nuclear fusion reactor based on the half-life of uranium. It can be seen that as long as uranium has been used, it will leave long traces. There is a huge gap between natural nuclear reactors and man-made reactors in terms of energy levels. Therefore, after the disappearance of human beings, the used nuclear reactors will still leave very obvious traces even if hundreds of millions of years have passed.
As long as a new intelligent civilization can discover nuclear reactors used by humans, it can prove that humans once existed through the half-life of uranium. In addition to the traces of human civilization on the earth, there will also be traces of human exploration in space and other planets.
Compared with the earth’s environment, the space environment and the environment of some alien planets are more conducive to the long preservation of traces. Space is an environment close to a vacuum. After human technology products arrive in space, they can be stored for a long time. If a new intelligent civilization has also entered the age of science and technology and out of the earth, then it will be able to see the space junk and know the glory of mankind.
In addition, our probes reach other planets and use nuclear energy. For example, the Mars probe Curiosity uses nuclear energy. As we said before, nuclear energy can leave traces even after hundreds of millions of years. Therefore, once a new intelligent civilization starts the exploration of Mars, it may be able to find traces of human existence on Mars.
The stronger the technological strength of a civilization, the longer it will last for the things left behind. If it reaches the second level of civilization, it will have the ability to build the Dyson Sphere. This kind of magnificent man-made structure that wraps the stars will leave a very obvious trace even if the civilization has disappeared for hundreds of millions of years.
And there may be many traces of such a powerful civilization in the universe. As we said earlier, the reason why human beings can’t find an alien civilization is that the alien civilization has disappeared. If an interstellar civilization is extinct and disappeared due to a disaster, it is estimated that there will be many traces of civilization in the parent galaxy where they live. As long as we can find such traces, it is of great significance to mankind.
Of course, to search for the remains of alien civilizations, you need to go to other galaxies, and to achieve this ability, our spacecraft must at least achieve sub-light speed. This speed is still too far away for the current humans, and we don’t know when humans will hope to achieve interstellar navigation.