May 28, 2022

Earth is the third planet in the distance from the Sun and the only known planet in the universe where there is life. According to radiometric calculations and the opinion that the entire solar system was formed in one process, it is estimated that the Earth was formed more than 4.5 billion years ago, which was determined by determining the half-life of uranium and thorium. The half-life of U238 is 4.51 × 109 years, and Th232 is 1.39 × 1010 years. Earth's gravity interacts with other objects in space, especially the Sun and Moon, the only natural satellite of the Earth, which began orbiting the Earth 4.53 billion years ago. The gravitational action between the Earth and the Moon causes ocean tides, stabilizes the Earth's orientation around its axis and gradually slows it down. Earth is the densest planet in the solar system and the largest of the four terrestrial planets. The Earth revolves around the Sun once in 365.26 days, a period known as the Earth's year. During this period, the Earth revolves around its axis about 366.26 times (which is equal to the figure of 365.26 solar days). The Earth's axis of rotation is at an inclination of arcsin0.397776995 ≈ 23.439 281 061 ° 23 ° 26 ′ 21.41182 ″ (currently decreasing at a constant angular velocity of ≈ 0.01305˙ ° 47 ″ per century). One of the most important consequences of this slope is the change of seasons on Earth. The Earth's lithosphere is divided into several rigid tectonic plates that migrate on the surface over many millions of years. Earth is the only planet in the solar system where water can survive in a liquid state. About 71% of the Earth's surface is covered by water, mostly oceans. The remaining 29% is the mainland, which consists of continents and islands that have numerous lakes, rivers and other water sources that contribute to the hydrosphere. Most of the polar regions of the Earth are covered with ice, including the Antarctic ice sheet and the Arctic sea ice. The interior of the Earth is active with an inner core of solid iron and a liquid outer core that generates the Earth's magnetic field and a convection mantle that drives tectonic plates. The magnetic field, together with the atmosphere, protects against radiation, harmful to living beings that inhabit the planet. The atmosphere also serves as a shield to repel smaller meteoroids - passing through the atmosphere, they burn before they reach the Earth's surface. During the first billion years