A layer of atmosphere surrounds the Earth, often referred to as an “insulating blanket”. Humanity and all forms of life exist at the bottom of this invisible and intangible layer. Within this atmosphere, many fascinating natural phenomena occur, ensuring the survival of life.
The composition of the atmosphere is quite complex. In addition to oxygen and nitrogen, it contains hydrogen, carbon dioxide, helium, neon, argon, krypton, xenon, ozone, and more. Nitrogen makes up 78.09% and oxygen constitutes 20.95% of the total volume of air, while the remaining gases account for less than 1%. The atmosphere also contains a certain amount of water vapor and various types of dust particles. These substances are crucial for the formation of clouds, rain, fog, and snow.
Although the air in the atmosphere is invisible, it has immense weight. According to scientists’ estimates, the layer of air enveloping the Earth weighs over 500 billion tons. Without the outward pressure of the atmosphere, humans would be crushed into a pulp. Due to the Earth’s gravitational force, 9/10 of the atmospheric weight is concentrated in the lower atmosphere within approximately 16 kilometers of the surface. The air becomes thinner the farther one moves away from the ground.
The thickness of the atmosphere is roughly 2,000 to 3,000 kilometers. Due to the varying properties of the air at different altitudes, meteorologists have divided the atmosphere into several layers:
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Layers of the Atmosphere |
– The layer closest to the ground is called the troposphere. Its average thickness at mid-latitudes is 16-18 kilometers, while at the poles, it ranges from 7 to 10 kilometers. The characteristic of the troposphere is that the air temperature decreases as altitude increases. Air in the troposphere moves vigorously both vertically and horizontally, causing water to change into all three states and resulting in numerous physical changes. Phenomena such as rain, hail, wind, snow, frost, and fog all occur in this layer.
– Above the troposphere, extending up to 50 kilometers, is the stratosphere. Here, the air is thin, with very little water and dust, and air movement is predominantly horizontal and stable, making it ideal for aircraft.
– From the stratosphere up to an altitude of 85 kilometers is the mesosphere. The temperature in this layer decreases further, reaching a low of -90 degrees Celsius. The upper part of this layer contains some water vapor and occasionally features a few silvery clouds known as noctilucent clouds.
– The layer of air extending from 85 kilometers to 500 kilometers is called the thermosphere. A defining characteristic of this layer is that temperatures increase with altitude; at 400 kilometers above the Earth’s surface, temperatures can reach around 3,000 to 4,000 degrees Celsius. Oxygen and nitrogen in this layer exist in an ionized state, which is why it is referred to as the ionosphere. Radio waves emitted from various locations on the Earth’s surface must reflect off the ionosphere to be transmitted worldwide.
– Above the thermosphere is the exosphere. Its lower boundary is around 800 to 1,000 kilometers, and its upper boundary extends up to 3,000 kilometers. This region serves as a transition zone between the Earth’s atmosphere and outer space. Due to the extremely thin air and high temperatures, some molecules and atoms move at high speeds, struggling to escape the Earth’s gravitational pull and venturing into outer space. Therefore, this layer is also referred to as the escape layer.
