Shulou(Shulou.com)11/24 Report--

Introduction:

"the state is in danger of tiring the eggs, and the living creatures are in urgent need." The urgency of being upside down is often used to describe the extremely difficult situation, which comes from the ugliness of Mencius and grandson of Mencius in the warring States period: "Today, in the country of Wansheng, the policy of benevolence and the pleasure of the people is like solving the problem of hanging upside down." The natural laws of pros and cons, north and south, and left and right have constructed the safe house for the survival of life on earth. They not only provide the natural law for natural evolution, the growth of all things and the reproduction of life, but also fix the definition of the rise and fall of our civilization in the east and the west, north and south and the square. When some natural rules are broken, people will inevitably panic.

Since explorers first pinpointed them in the early 19th century, the magnetic North Pole has been crawling northward-more than 600 miles (1100 kilometers). In fact, it is moving faster now, and scientists estimate that the North Pole moves about 40 miles a year, rather than 10 miles a year at the beginning of the 20th century. We need to accept the fact that the earth's north and south poles are changing, perhaps until one day ushered in a geomagnetic reversal. At first glance, it seems that the Creator really wants to "hang" the creatures of the earth, but will this be the new sword of Damocles on the head of human civilization?

The magnetic pole path, which was directly observed after 1831, reconstructed 01 for paleomagnetic data before 1831. What is the Earth's magnetic field? The geomagnetic field produces a natural magnetic phenomenon in the interior of the earth. The earth's normal magnetic field accounts for about 99% of the earth's magnetic poles, similar to a magnetic dipole (magnetic dipole): one pole is near the north pole and the other is near the south pole. Unlike classic bar magnets or decorative magnets on refrigerators, the material that controls the earth's magnetic field moves around, resulting in the remaining 1% of the external magnetic field and magnetic anomalies. Geomagnetism and geomagnetism existed at the beginning of the birth of the earth, and modern physics also regards magnetism as one of the four basic physical forces that dominate the physical universe.

Schematic diagram of the earth's magnetic field, but where does the earth's magnetic field come from? This outstanding problem not only perplexes the research of theoretical physicists, but also shakes the foundation building of geophysics. In order to answer this question, scientists have successively put forward permanent magnet theory, internal current theory, charge rotation theory and so on. Finally, electromagnetic induction theory, also known as generator theory, is widely accepted.

Astronomer Larmor proposed through the observation of the sun: "the internal cyclic motion may work in the form of a self-excited motor and keep the magnetic field permanent at the cost of some energy from the internal cycle." This view was later applied to the study of the geomagnetic field and gradually developed into a generator theory: the earth can magnify the geomagnetic field to its present state through the flow of liquid iron in its outer core. In order to maintain such a geomagnetic field, the source of energy is the thermal convection caused by the temperature difference between the core and the mantle. Simply put, geomagnetism is formed because the earth's solid iron core is surrounded by a fluid ocean of hot liquid metal-liquid iron generates an electric current in the flow of the earth's core, which in turn produces a magnetic field. Compared with other theories, generator theory (also known as MHD generator theory) has been more confirmed in observation, experiment and theoretical research, and has become a more accepted point of view in geophysics at present.

Magnetic field generation map 02 geomagnetic reversal is a rule, but not an exception. In recent years, observations have found that there are some abnormal regions of the magnetic field on the earth, which are generally regarded as a precursor of a major shift or even reversal of the earth's magnetic field. The intensity of the magnetic field in the earth's region is constantly weakening, and the attenuation rate has increased rapidly in the past decade. For example, the annual attenuation rate of the geomagnetic anomaly in the South Atlantic is ten times that of other anomalies. At the same time, the area of other geomagnetic anomaly areas also tends to expand. For a moment, the panic of geomagnetic reversal attracted global attention, and even many apocalyptic theorists believed that geomagnetic "abnormal" changes could lead to the destruction of the earth.

In fact, contrary to the perception in our daily life, geomagnetic reversal is the rule rather than the exception. Scientists estimate that there have been at least hundreds of reversals in the past 3 billion years. If you lived about 800,000 years ago, with a compass in your hand and facing what we call the north, the pointer would point to the south. In the past 2000 years, the earth has entered a mode of pole reversal about every 200000 to 300,000 years. In the long geological history, change is eternal.

The closest long-term geomagnetic reversal to mankind was the Brennis-Songshan reversal, which occurred 780,000 years ago; the polar reversal of the geomagnetic field lasted about 20,000 years. However, not all geomagnetic reversals last for tens of thousands of years, and sometimes the geomagnetic field reverses twice in a short period of time, geologically known as "geomagnetic drift". For example, the Laschamps geomagnetic reversal 410, 000 years ago lasted only 1, 000 years, and the poles reversal lasted only 250 years. From the data of geomagnetic changes, it is not difficult to see that magnetic pole reversal is a common phenomenon on the geological time scale, but it is actually relatively difficult to encounter in the scale of human life; at the same time, geomagnetic reversal is a slow process that occurs in hundreds or thousands of years, which is not an one-time complete reversal, so it can be predicted to a certain extent. What is the effect of geomagnetic reversal? Now it seems that magnetic compass manufacturers will be looking forward to this new business opportunity. But there is no denying that we human beings still know very little about the earth, and we have to guard against some risks, even if the probability of it is very small.

03 what is the most important earth resource affected by geomagnetic reversal? Many people's first reaction is water or oxygen, and few people mention geomagnetism, but in fact, the role of geomagnetism is far beyond public imagination. Because the solar wind contains a large number of high-energy charged particles, it will be affected by the magnetic field and bypass the earth. If the earth's magnetic field disappears, then the high-energy charged particles will enter the atmosphere, which will bring a devastating blow to the earth's life. Geomagnetic field is not only like a shield to protect the survival and development of human beings, it is also the cornerstone of many modern science and technology. With the introduction of the compass into the western world, the geomagnetic field has not only provided extremely important help for human navigation, but also promoted the development of many science and technology-the relative stability of the geomagnetic field is also an important reason why it has become the carrier of information exchange.

The reason for concern about the magnetic field is simple: to protect us out of concern for the geomagnetic field, some cautious scientists have begun to remind people of the dangers of geomagnetic reversal. Cooper (2) of the University of Adelaide and others analyzed the correlation between radiocarbon records of New Zealand swamp spruce trees and magnetic field intensity before and after geomagnetic polarity conversion, and used supercomputers to simulate the consequences of Laschamps geomagnetic reversal about 41, 000 years ago. They found that the weakening of the geomagnetic field affected the atmosphere's absorption of sunlight, leading to dramatic climate changes, which lowered the earth's temperature at that time, and eventually led to the extinction of many large mammals in Australia, such as woolly mammoths and giant wombats. This study confirms that the reversal of the geomagnetic field has contributed to the extinction of species, and many people worry that the same tragedy will happen to humans. At the same time, Alanna Mitchell warns "the force that created the world, and could bring about its end" in her book The Spinning Magnet. If the stability of the location and intensity of the geomagnetic field no longer exists, then what awaits the earth is a future without power grids and electronic communications. This will be a "doomsday" blow to modern society.

42000 years ago, humans left more and more red ochre handprints in cave paintings. Ochre is an ancient sunscreen, which is believed to be evidence of enhanced ultraviolet radiation, which is confirmed by the weakening of the earth's magnetic field leading to the weakening of ozone. There is no need to argue that if a geomagnetic reversal occurs, it will indeed bring about an ecological disaster. But the question is whether the geomagnetic reversal has occurred. When will it happen? Will it happen on the scale of human civilization?

Conclusion: human society is indeed faced with "upside down", but it is far from the degree of "urgency". People always have to face the predicament that is certain to happen, rather than challenging the illusory opponent. In fact, current observation techniques and prediction methods do not confirm the urgency of the imminent geomagnetic reversal, and our sense of crisis may only occur in science fiction. Instead of worrying about the possible end of the world caused by geomagnetic reversal, it is better to reduce mental internal friction and find a new way to observe geomagnetic changes.

Excessive anxiety will become pessimistic in the future!

reference

1. J. Larmor, in A Source Book in Astronomy and Astrophysics, 1900-1975, R. L. Kenneth, G. Owen, Eds. (Harvard University Press, Cambridge, MA and London, England, 1979), pp.

2. A. Cooper et al., A global environmental crisis 42000 years ago. Science 371,811,818 (2021).

This article comes from the official account of Wechat: stone popular Science Studio (ID:Dr__Stone), author: Shao Jingying, American editor: Liu Yuling

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