Note: is there a civilization in prehistory? (Figure / Regis / Reuters) NASAs Goddard Space Science Institute is a world class Institute of climate science, and Gavin Schmidt is the director of the Institute. One day last year, Adam Frank came to the Goddard Institute. He came here to exchange with an unusual idea. Adam Frank is an astrophysicist. In order to better carry out his work, he began to study global warming from the perspective of astrobiology. The so-called astrobiology is the study of the existence of biological conditions on the celestial body and the existence of biological objects on the celestial body, which can bring a greater vision to scientists. Now, the question of the research is that Frank and Schmidt are trying to understand whether the industrial civilization on the planet will cause specific changes in the planets climate because of a specific activity. Frank went to the Goddard research institute that day. He hoped to get some insights from climate science, and he thought he might find a partner. Then Frank came to Gavins office. While Frank was talking excitedly, Gavin interrupted him. You stop first, the earth has a history of billions of years, how long have we been human, perhaps there have been other industrial civilizations on earth before we appear! Gavin said. Frank stopped and his chin fell on the floor. Before that, we should have heard and paid attention to the topic of extraterrestrial civilization, but now Gavin is talking about prehistoric civilization. The prehistoric civilization may have existed hundreds of millions of years ago, even hundreds of millions of years ago, after a glorious period of glory to destruction, and then new glory and new destruction, thought of this, Frank can not help a gust of dizziness. Then Frank went on to Gavins words and said, yes, no one can deny this possibility. But can we prove that industrial civilization existed really long ago? At least for now, we cant go back to the past. But after the first dialogue between Frank and Gavin, a new study was launched, which is published in the latest issue of the International Journal of astrobiology. We need to note that Gavins acute problem is not only studying the past of mankind, but also helps us predict and face the future better. Before that, we were accustomed to guess the vanishing civilization based on archaeological discoveries, such as the wreckage of a statue or underground building. Prehistoric artifacts can really help us to study, but if we only rely on these things, we can only trace back thousands of years. If we want to study tens of millions of years or even billions of years ago, things will become very complicated. For example, even with industrial civilization, the devices made by these civilizations may have turned into powder in the millions of years. What is the direct evidence of industrial civilization? According to the present society, we will think of cities, factories and roads. But even if these traces existed about 2000000 years ago, it is hard to find them today. 2 million 600 thousand years ago, that is, the Quaternary period in the geological period. For a specific example, scientists found the oldest extant mass of earths surface monuments on the earth in the inner gaff desert in southern Israel, and this oldest trace is only 1 million 800 thousand years old. There are also traces of older ones, such as the geological cross sections we can observe, such as some cliffs or cross sections of stones. But after tracing back to the Quaternary, everything on the earth has become dust under the action of external forces such as geological movement and climate movement. Moreover, if we want to discuss the events of millions of millions of years ago, the civilization we talk about (if it exists) is different from what we are now. Modern Homo sapiens left traces on the earth, but the earliest traces of Homo sapiens we found were only about three hundred thousand years old. Therefore, Gavins prehistoric civilization means that we are talking about another species, which Gavin calls the Silurian conjecture. The Silurian was the last period of the early Paleozoic, and the third period of the Paleozoic. It began about 440 million years ago and ended 410 million years ago. Perhaps some intelligent reptiles appeared at this time. Therefore, if an ancient animal had established an industrial civilization in a certain period of time long before our time, could our researchers find the exact and clear evidence? For example, in the Paleocene period around 60 million years ago, some early mammals that had briefly appeared may have created civilization. So, there will be fossils left. But the proportion and possibility of fossilization after extinction are minimal, because fossilization will have many conditions, such as time and habitat. Therefore, if an industrial civilization existed for 100 thousand years, it would be difficult for us to find traces of modern civilization. You may feel that 100 thousand years are too short, but you have to realize that the first industrial revolution started around 1760 is only 260 years away. That is to say, the industrial civilization of our generation has only existed for 260 years. All the direct evidence will disappear in millions of years. Considering this, what kind of evidence will exist? The best answer is to look at the modern man himself: if we die, what will we leave behind for the longest time? What clues will be left for our activities? Our industrial civilization has globalized, and the collective activities of human beings have left a variety of traces, with modern technology as a reference, and the scientists of the next 100 million years can also detect our traces. For example, in order to meet 7 billion people to have something to eat, a large and extensive use of chemical fertilizer is needed, but it also means that we turn the nitrogen on the earth into food production. Some of the use of nitrogen fertilizer in the farmland will flow into the river, and the nitrogen fertilizer can produce higher concentration of microbial activity in the river sea intersection area, which causes a large number of algae in the intersection area to absorb the oxygen in the water, and the scope of the dead zone of the ocean is also expanded, and these changes should be revealed in the sedimentary layer. Researchers in the future world should be able to detect the characteristics of nitrogen left in our time from sediments. For example, in order to produce electronic products, we will use a lot of rare earth elements, and the rare earth ore in nature will be exploited in large quantities. Nowadays, there are many such elements on the earths surface, which is the result of human activities. These elements may also be shown in future sediments. Even the synthetic steroids we invented and used will become common. These characteristics can also be detected in the geological layer 10 million years later. And then the plastic that can be seen everywhere. Research shows that more and more plastic garbage is accumulated around the worlds seabed, some of which are in the coastal areas, some in the deep sea basins, and even in the Arctic. The wind, the sun and the ocean current ground the pile of plastic into powder, which makes the ocean full of tiny plastic particles that eventually sink to the bottom of the sea to form a special layer that can be kept for quite a long time and can be calculated in geological time. The biggest question is, how long will our civilization traces last? In this study, scientists found that every trace of modern man has the potential to become a future sediment. Ironically, however, the most likely symbol of the existence of human advanced civilization may be plastic, which is our by-product and has been a threat to the ecological environment. When we burn fossil, we will discharge carbon into the atmosphere, and the atmosphere is necessary for our life. The more fossil fuels we burn, the greater the balance of these carbon isotopes will happen. Atmospheric scientists call this transformation the Hughes effect or the suus effect, which can also be referred to as the industrial effect, that is, the history of fossil fuels such as coal and petroleum is very long, and the time of existence is very long, most of which have been decayed, so the proportion of C12 in fossil fuels is relatively high. Since the industrial revolution, the burning of a large number of fossil fuels has made the high concentration of C12 into the atmosphere, resulting in a decrease in the ratio of C14 in the atmosphere and the change in the ratio of carbon isotopes. In addition, the increase of temperature also leaves isotope signals. Future chemists will be able to detect these obvious changes through chemical analysis of the rock strata that we are exposed to in this era. In addition to the peak values of elements and ratios, the human strata may also present a brief peak in nitrogen, plastic nanoparticles, and even synthetic steroids. So if our remains can be left to the future and to be detected by future scientists, is the signal in modern rocks telling us the prehistoric civilization? Are these events indicative of the existence of non human industrial civilization? Almost certainly, not. Although there is evidence that the warmest climates of the Paleocene Eocene may be caused by the release of a large amount of buried fossil carbon into the air, the time scale of these changes is the key. The isotopic peak values of the Paleocene Eocene climatic warmest period also rise and fall in the hundreds of thousands of years. But what makes the human world so remarkable in the history of the earth? The answer is the speed at which we discharge fossil carbon into the atmosphere. In a period of geological time, the earths carbon dioxide is even higher than it is today, but in a history of billions of years back to earth, there has never been so much buried carbon in the atmosphere at such a fast speed. Therefore, the isotopic peaks we have seen in geological records may not be sufficiently abrupt, nor can they sustain the grand assumption of industrial civilization in the Silurian period. But there is still a problem. If the industrial civilization of an early species existed for a relatively short period of time, we might not be able to find the trace of civilization easily. The peak of the Paleocene Eocene warmest climate shows us mainly the response of the time scale of the earth to the cause of this situation, but not necessarily the time scale that causes the cause, which means that the two sentences may be more complicated, meaning that we can see the corresponding change of the earth through the peak, but it is not easy. See the reason for the change, because the length of the time span is not well established. Therefore, in order to find the evidence of some kind of short-term civilization in prehistory through ancient sediments, we need to take advantage of enough professional and innovative methods. This is a big problem, not a general paper. Neither Gavin nor Frank believed that the earth had carried a Paleocene civilization with a history of 50 million. But if someone asks us if we can really observe the traces of ancient industrial civilization, we can only answer honestly, that we can speculate on the general influence of any civilization on the earth. This is also the perspective of astrobiology for climate change. Civilized architecture means collecting energy from the earth to carry out construction work. Once civilization reaches the real planetary timescale, the civilization will generate some feedback on its system. This is especially in line with young civilization, such as human civilization, which is still developing in technological capability. But there is no such thing as a free lunch. Civilization may be a savage success. For example, although the use of fossil fuels provides power for industrial civilization, it also has an impact on human health. Although some energy, such as solar energy, has a lower negative impact, human beings will not be able to drive a global civilization if it does not have a certain impact on the earth. As climate change intensifies, people need to find energy that has less impact on the environment, so that the negative impact of the individual will also be reduced. Therefore, if a civilization becomes more persistent, the less the civilization has on the region, the signal and traces left by the civilization will be smaller and more difficult to find. In addition, the work of Gavin and Frank has also opened up a speculative possibility that some planets have ever staged the construction and collapse of civilization, and these civilizations may have been driven by fossil fuels. If a civilization uses fossil fuels, the climate change triggered by the civilization may lead to a significant drop in oxygen content in the ocean. This level of hypoxia, also known as ocean hypoxia, will create necessary conditions for the generation of fossil fuels such as coal and petroleum. In this way, the destruction of a civilization will sow the seeds of a new civilization in the future. But even if civilization is gone, we must protect our homeland and our earth. Source: NetEase science editor: Guo Hao _NT5629 As climate change intensifies, people need to find energy that has less impact on the environment, so that the negative impact of the individual will also be reduced. Therefore, if a civilization becomes more persistent, the less the civilization has on the region, the signal and traces left by the civilization will be smaller and more difficult to find. In addition, the work of Gavin and Frank has also opened up a speculative possibility that some planets have ever staged the construction and collapse of civilization, and these civilizations may have been driven by fossil fuels. If a civilization uses fossil fuels, the climate change triggered by the civilization may lead to a significant drop in oxygen content in the ocean. This level of hypoxia, also known as ocean hypoxia, will create necessary conditions for the generation of fossil fuels such as coal and petroleum. In this way, the destruction of a civilization will sow the seeds of a new civilization in the future. But even if civilization is gone, we must protect our homeland and our earth.