Sky

The sky is the region between World and outer space, typically encompassing the upper part of the atmosphere where light and weather phenomena interact. To our observations, the sky appears as an infinite such as when viewed from Earth. However, in reality, the sky is part of the atmosphere and consists of the combined layers of the atmospheric envelope. Its blue appearance during the day is due to the scattering of Sun light by molecules in the atmosphere, which preferentially disperses blue wavelengths. At sunset, the sunlight travels a longer long path through the atmosphere, causing red and orange hues to dominate.

The sky is also shaped by weather phenomena and sky objects within the atmosphere. Stars, clouds, winds and rain are among the elements that constitute the sky. Therefore, the sky is not merely a visual effect but a region shaped by the influence of the atmosphere and weather systems.

The sky

Layers of the Atmosphere

Atmosphere is a gaseous layer system that surrounds our planet. These layers regulate the changes observed in the sky, weather phenomena, and the processes essential for sustaining life. The atmosphere consists of five main layers: the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Each layer has unique characteristics and interacts differently with Earth.

Layers of the Atmosphere

1. Troposphere (up to 8–15 km above Earth’s surface)

The troposphere is the lowest layer of the atmosphere and is where most weather phenomena observed in the sky occur. As the layer closest to Earth, it contains the majority of the atmosphere’s air. Weather events such as clouds, rain, snow, and wind take place within this layer. Because it contains water vapor, 99 percent of all water vapor in the atmosphere is found here.

The upper boundary of the troposphere is called the tropopause. This is the level at which temperature stops increasing and begins to decrease with altitude. As height increases, the air becomes colder.

2. Stratosphere (15–50 km)

The stratosphere lies directly above the troposphere. A key feature of this layer is the presence of the ozone layer. Ozone absorbs harmful ultraviolet radiation, protecting Earth from the Sun’s harmful effects. The air in the stratosphere is more stable than in the troposphere, which is why aircraft typically fly within this layer.

The upper boundary of the stratosphere is called the stratopause. In this layer, temperature increases with altitude due to the absorption of ultraviolet radiation by the ozone layer.

3. Mesosphere (50–80 km)

The mesosphere is the third layer of the atmosphere and contains the coldest regions of the atmospheric envelope. The air here is extremely thin and cold. Temperature decreases with increasing altitude. Meteors entering this layer burn up, producing the streaks of light known as “shooting stars” visible in the night sky.

The upper boundary of the mesosphere is called the mesopause. Temperatures here can drop as low as −90°C.

4. Thermosphere (85–500 km)

The thermosphere is the fourth layer of the atmosphere and is characterized by very high air temperatures. This increase in temperature is caused by high-energy radiation from the Sun. Temperatures in the thermosphere can reach up to 1,500°C. However, due to the extreme thinness of the air, these temperatures do not affect the human body.

The ionosphere within the thermosphere reflects radio waves, enabling long-distance communication and producing spectacular light phenomena such as the northern lights.

5. Exosphere (500 km and beyond)

The exosphere is the outermost layer of the atmosphere and marks the transition from Earth’s atmosphere to outer space. The gases in this layer are extremely thin and sparse. The gases found in the exosphere are light elements such as hydrogen and helium. The upper boundary of the exosphere is where the atmosphere ends and merges with space.

The sky is in fact part of the atmosphere, formed by the combination of its different layers. These layers play a crucial role in shaping weather patterns and climate on Earth. The blue color we see in the sky, along with weather phenomena such as clouds, rain and wind, arise due to the dynamic structure and layered composition of the atmosphere. Each layer performs a distinct function in its interaction with Earth and is essential for sustaining life. The sky has always been a source of wonder and inspiration, and understanding how the atmosphere functions allows us to better comprehend this natural system.