Earth Sciences

Focusing on the question of why there is a Great Rift Valley in East Africa, this paper introduces the scale, shape and branches of the Great Rift Valley in East Africa, as the largest continental rift system on earth, and expounds two different hypotheses and evolutionary predictions about its formation mechanism based on plate tectonics theory in the scientific community.

Focusing on the question of why there are very ancient rocks on land but not on the ocean floor, this paper introduces the definition, scope and composition of the continental crust and the oceanic crust. By explaining the life journey of the oceanic crust from the new generation of the mid-ocean ridge to the subduction and extinction of the trench, and the characteristics of the continental crust. The low density and difficulty in subduction and remelting explain the reason why there are rocks more than 3.8 billion years old on the land and the oldest rocks on the ocean floor are no more than 200 million years old.

Focusing on the question of "why can continents drift", this paper introduces that the dynamic mechanism of tidal force and centrifugal force proposed in the Wigner Continental Drift Hypothesis is not recognized due to weak power. With the development of geophysics, scientists have proposed the theory of ocean expansion and developed the theory of plate tectonics through multiple ocean exploration evidences, explaining that the driving force for continental drift comes from material convection in the asthenosphere. At the same time, it introduces the basic theory of plate tectonics and the characteristics of crustal movement at plate junctions.

Focusing on the question of whether the continent was once a single piece, this paper introduces the early understanding that the shapes of the continents on both sides of the Atlantic Ocean could be pieced together at the end of the 16th century, to the process and core content of the German meteorologist Wigner's proposal of the continental drift hypothesis based on various fossils and geological evidence, and then to the development of paleomagnetism, remote sensing, electronic computers and other technologies after the 1950s providing new evidence for continental drift. In turn, a complete history of seabed spreading theory and plate tectonics theory was developed.

Focusing on the question of "why can scientists know the age of rocks", this paper introduces the principles, characteristics and application scenarios of the two rock age determination methods, relative geochronology and absolute geochronology, and explains that scientists can accurately determine the age of various rocks by selecting appropriate minerals and isotope decay systems.

This paper focuses on "Why do rocks also have ages" and introduces the formation opportunities of the three types of rocks on the earth: igneous rocks, sedimentary rocks, and metamorphic rocks. It shows that rocks have ages. The oldest known one is the 4.4 billion-year-old rocks found in Australia. Moreover, the earth continues to produce new rocks through volcanic activity, sedimentation, etc., and it also expounds the significance of studying rock age, that is, rocks are the most important records left by the earth's evolution process. It can reveal major events in the earth's evolution and their timing.

This article explains the reason why marble has beautiful patterns. It introduces that the scientific name of marble is marble. It is a metamorphic rock formed by the metamorphism of limestone. Because different impurities such as magnesium, iron, and clay mixed in the limestone react differently during the metamorphism process, various beautiful patterns are formed on the white marble. At the same time, it is mentioned that marble can be used as a building decoration material, including Taj Mahal, white marble carvings, etc.

This paper focuses on the question of "why are rocks on the earth so different?" and points out that rocks are composed of various minerals or amorphous compounds in different forms. They can be divided into three categories: igneous rocks, sedimentary rocks, and metamorphic rocks. The formation mechanisms of the three types of rocks are introduced respectively, and it shows that the three major rock types are both obviously different and related to each other, and can transform into each other to form interlocking circular chains.

Focusing on the question of "Why are there beautiful auroras over the polar regions", this paper introduces the appearance, origin of their names and relevant historical hypotheses of auroras, and explains in detail the three major elements of the formation of auroras (solar wind, Earth's magnetic field, atmosphere) and the principle of luminescence, explaining the factors influencing the color and intensity of auroras.

Focusing on the question of "why does the geomagnetic pole reverse", this paper introduces the concept of geomagnetic pole reverse, the occurrence of magnetic pole reverse in the history of the earth, especially in the past 4.5 million years, and the current two mainstream views in the scientific community on the causes and laws of geomagnetic pole reverse, pointing out that scientists have not yet reached a unified conclusion on this.

Focusing on the question of "why does the earth have a magnetic field", this paper introduces the important attributes and early applications of the earth's magnetic field, combs various hypotheses explaining the causes of the earth's magnetic field, and focuses on explaining the content, research progress and two major problems that still need to be solved.

Focusing on the question of how the composition of the earth's interior is revealed, this paper introduces the current situation of limited depth of human drilling into the earth's interior, explains the methods of using surface rocks and xenoliths, seismic waves, and simulated high temperature and high pressure experiments to explore the earth's interior, and explains the current Known conclusions on the main components of the earth's crust, mantle, and core layers.