Earth Sciences

This paper focuses on the depth at which humans can drill underground, pointing out that existing technology can only drill to the earth's crust. It introduces the Moho plan, the specific situation of ultra-deep drilling in many countries, and drilling results, such as confirmation of seabed expansion and discovery of high-temperature resistant anaerobic bacteria in deep underground.

This paper introduces that scientists use seismic waves to study the interior of the earth. Through the discovery of Moho surface and Gutenberg surface, the earth is divided into crust, mantle and core. After subdivision, the outer core of the earth core is liquid, so the earth is compared to an uncooked egg with liquid outer core. The scientific basis of this analogy is explained.

This article focuses on "Why should we set a standard time zone?" It introduces that in the past, people relied on the sun to determine time. In the railway era, traffic chaos was caused due to solar time changing with longitude. Britain took the lead in adopting Greenwich Mean Time, and later, international conferences determined time zone division rules, and countries gradually implemented, China changed from multiple time zones to unified Beijing time and other core contents.

This paper focuses on the reasons for the earth's rotation. First, it explains that the alternation of day and night stems from the earth's rotation and Copernicus's related theories. Then, based on the law of conservation of angular momentum for the formation of the solar system, it explains the rotation of celestial bodies due to the initial rotation and conservation of nebulae. It is also mentioned that the earth's rotation speed will change due to the influence of gravity, internal matter, impact, etc.

This article sorts out the context of the exploration of the age of the earth: from mythological speculations such as the creation of the sky at Pangu and the creation of Christianity, to early scientific explorations such as Halley and Kelvin (although rough, breaking through religious constraints), to isotope dating methods based on radioactive decay. Finally, the age of the earth was determined to be about 4.57 billion years through meteorites and lunar rocks, and it also involved key nodes in the earth's evolution.

The earth's "childhood" was full of disasters. It was baked at high temperatures and hit by meteorites. The surface of the earth formed a magma sea above 2000 degrees Celsius (about 1700℃), which was not suitable for life. After the large-scale impact ended 3.8 billion years ago, the earth became slightly more peaceful. Although there were small impacts in the future, life evolved tenaciously and mass extinctions also provided development opportunities for vulnerable organisms.

This article focuses on the issue of land formation, showing that the Earth is the only planet in the solar system that has both continental and oceanic crusts. Through research on zircon from Jack Mountain in Western Australia, it is pointed out that the oldest crust of the earth appeared 4.4 billion years ago, and the permanent continental crust was formed in large quantities in the Archean era. It is also mentioned that water is crucial to the formation of the continental crust.

This paper discusses the source of Earth's water, but there is no definite answer at present. It is known that volatile matter precipitation from the magma sea during cooling or mantle exhaust can form primitive water. There is also speculation that it is brought by water-containing comets in the outer solar system; it is also mentioned that the preservation of water requires gravity, magnetic field and other conditions, compared with the lack of water on Mars due to lack of magnetic field.

This paper focuses on the relationship between the earth and the sun, and introduces the nebula hypothesis of the origin of the solar system put forward by the German philosopher Kant in 1755. It explains that the nebula of the solar system formed the sun through processes such as supernova explosion 5 billion years ago, and the collision formation mechanism between the earth and the moon. The final conclusion is that the earth is the sun's "follower" and the moon is the earth's "follower".

The article "Why Study the Earth" points out that the Earth is the only planet in the universe with humans. It breeds life and contains infinite mysteries. Humanity needs to explore its laws to deal with challenges such as resources and the environment. Earth science is an important support for promoting development and achieving sustainability.