4.5 billion years ago, the dust floating in space was the first rocky planet that ended its life because of the explosion of a huge ancient star.
Since its establishment, the earth can also be divided into five "descendants", which have existed since ancient times: Archean, Proterozoic, Paleozoic, Mesozoic and Cenozoic. Some representatives are further divided into "disciplines". For example, Paleozoic is divided into Cambrian, Ordovician and Silurian, Devonian, Carboniferous and Permian, Mesozoic is divided into Triassic, Jurassic and Cretaceous, and Cenozoic is divided into Tertiary and Quaternary. This is a rough division. The historical period of the earth is called "geological age", and different geological periods have different characteristics.
It can be traced back to 240 million years ago. Lithosphere, hydrosphere and atmosphere have been formed on the surface of Archean earth, but the crust is very unstable, volcanic activity is frequent, magma is 4 smirnoff, a vast ocean area, and bare mountains are everywhere on the land. Iron ore In this important era, the lowest primitive life began to emerge.
It can be traced back to Proterozoic from 240 million to 6 billion years ago. At this time, most planets are still hidden in the ocean. In the later period, there appeared a large area of land, seaweed and marine invertebrates with average Proterozoic primitive life on earth. about
Tracing back to 600 million years ago, 250 million years was Paleozoic. "Paleozoic" refers to the era of ancient life. At this time, there were thousands of animals in the ocean, and marine invertebrates flourished unprecedentedly. Later fish animals, fish, and a large number of breeding fish crawled and landed on land, becoming the ancestors of terrestrial vertebrates. Amphibians also have terrestrial ferns in the northern hemisphere, some as high as 30 meters. These tall and dense forests later turned into large coalfields.
The Mesozoic of the first 250-700 million years lasted about 65.438+800 million years, and reptiles and dinosaurs dominated for a while. At this time, there were primitive mammals and birds. Declining ferns and gymnosperms. Dense plants and large animals in Mesozoic, which later became huge coalfields and oil fields. Metal deposits formed in Mesozoic. & ltBR/ The latest stage of the Cenozoic era on earth has a history of only about 700,000 years in the shortest time. The surface of the earth at this time is basically the same as today. The great development of Cenozoic angiosperms has brought unprecedented prosperity to various herbivorous and carnivorous mammals. The development of natural creatures eventually led to the emergence of human beings, and ancient apes gradually evolved into modern humans. It is generally believed that human beings lived in the Quaternary, about 24 billion years ago.
Humans living on the earth have developed step by step to the present, gradually, at first glance.
Why is the earth round?
The earth is round, other planets are round, and we see that the bubbles in the air are round.
Due to the surface tension of liquid, bubbles and droplets are round.
Why the earth. The high temperature, high energy consumption and high density materials of the original BIGBANG are the same for every planet since the birth of the wheel on the earth. In an instant, this planet is a high-temperature liquid, and the same effect of surface tension on these planets lasts for a round. After hundreds of millions of years of cooling, the surface temperatures of some planets gradually decreased, and then protein gradually appeared. There is life, and this planet is the earth. Without this, it becomes the shape of other reasons, so it has been kept in a circle until now, in various sports.
How to prove that the earth is round?
Magellan's voyage around the world is an important achievement in the history of world navigation. From June 15 19 to September 1522, Magellan's successful voyage around the world not only opened up a new route, but also took risks. His expedition fleet proved that the earth is round and the earth is a sphere.
How big is the earth?
Humans live on this planet, the earth, which is one of the eight planets in the solar system. The average distance of the sun is 149597870 km (1 astronomical unit), which is the third on the planet and the fifth on the earth, and its equatorial radius is 6378.2 km.
The equatorial radius of the earth (1) is 6378.438+040km.
The average radius of the earth is R(A2B)637 1.004 km.
Equatorial circumference (2лa)40075 km
Earth surface (4 л R2) 510100 934km2/>; The volume of the earth is 4 π R311082 billion cubic kilometers =1.083 207 3x1kloc-0/2km3.
Earth mass: 5.9742×10.24 kg.
Average density is 55 15.3kg/m br/ > equatorial gravity: 9.780m/s 2 (0.997 32g).
The temperature of the earth
The core temperature is about 6880℃, which is higher than the surface temperature of the solar photosphere (6000℃). The highest explosion temperature of a hydrogen bomb on the earth can reach 1000000℃, which is the coldest place on the earth than the core temperature of the sun (1400℃, 16667℃). "Cold" in the northern hemisphere, East Siberia 167. "Cold" in the Southern Hemisphere of Antarctica, temperature1August 24th, 960. -88.3 degrees Celsius.
negative charge
Reason: The earth rotates from west to east, and the external geomagnetic field is negatively charged from the south magnetic pole to the north magnetic pole (that is, the north pole) to the ring current rotating in the opposite direction to the earth.