Earth's Characteristics and Atmospheric Layers

Characteristics of Earth as a Planet

Source: Earth was formed approximately 4.6 billion years ago by the agglomeration of matter subject to gravitational attraction.

Mass: Approximately 5,976 trillion tons (estimated from the formula of universal gravitation and gravitational acceleration).

Gravity: This force influences the arrangement of materials according to their density (less dense at the top, more dense at the bottom). On Earth, air, water, and rocks are arranged in this way.

Greenhouse Effect

Visible solar radiation penetrates the atmosphere and warms the Earth's surface. The Earth radiates heat as infrared radiation into the atmosphere; some of it escapes into space, and some is sent back to the surface. Increasing greenhouse gases in the atmosphere increases the temperature of the Earth's surface; the oceans warm, increasing the level of water vapor and reinforcing the impact.

Atmospheric Layers

• Troposphere: This is the layer that is in contact with the surface. Its thickness varies from 8 km at the poles to 16 km at the Equator, and its temperature decreases with increasing height (about 0.65°C per 100m altitude). Most meteorological processes take place here, including the greenhouse effect.
• Stratosphere: This layer rises to 50 km. The temperature remains constant at first and then increases with height. It contains the ozone layer, which filters ultraviolet radiation from the Sun, which is very harmful to living things. Because of this absorption, the temperature rises in the upper stratosphere.
• Mesosphere: This layer has a thickness of approximately 40 km. The temperature drops to -77°C at its upper limit. It contains no ozone or water vapor, although there are heaps of ice and dust. In this layer, meteorites that reach Earth become incandescent, forming what are known as shooting stars.
• Ionosphere/Thermosphere: This layer extends to 500 km. In it, gases are transformed into ions by absorption of solar radiation, a fact that allows the transmission radius around the curved surface of the Earth because the ionized gas acts as a reflector of some lengths. Radio waves are reflected in this layer, and polar auroras occur, a phenomenon that can only be seen near the poles.

Functions of the Atmosphere

1. Regulates the Earth's temperature through the greenhouse effect, maintaining it at an average of 15°C.
2. The upper layers of the atmosphere absorb short-wave radiation (X-rays and gamma rays), and the ozone layer absorbs ultraviolet radiation, protecting living things.
3. The atmosphere, in its interaction with the hydrosphere, forms the water cycle and determines the climate, while the interaction of these two systems with the Earth's surface results in the processes of weathering, erosion, and sedimentation.