Atmosphere and Its Layers

The envelope of air around the Earth is called the atmosphere. It is composed of nitrogen, oxygen, water vapour, and carbon dioxide, with other gases present in small quantities. The atmosphere is like a protective blanket that keeps our planet safe and helps support life. 

1. Troposphere: The troposphere, the closest layer to Earth's surface, is where we live and weather occurs. It is 8 to 15 kilometres thick and contains air, clouds, rain, snow, and storms. As we rise, the troposphere becomes colder. It is primarily composed of nitrogen and oxygen.
2. Stratosphere: The stratosphere, located 15 to 50 kilometres above the Earth's surface, is crucial as it contains the ozone layer, which absorbs most of the sun's harmful UV rays. As you rise, the stratosphere becomes warmer due to the ozone absorbing the sun's energy.
3. Mesosphere: The mesosphere, located 50-85 kilometres above Earth, is the layer where most meteors burn up, creating shooting stars. It is also the coldest layer, with temperatures dropping as low as -90°C (-130°F).
4. Thermosphere: The thermosphere, extending from 85 to 600 kilometres above Earth, is characterised by thin air and extreme temperatures up to 2,500 °C due to the sun's intense energy. This layer is where auroras occur and the International Space Station orbits.
5. Exosphere: The exosphere, the outermost layer of the atmosphere, extends from Earth's surface to space and is thin with few air molecules. Satellites orbit this layer, which gradually fades into outer space.

Layers of Atmosphere

• The atmosphere keeps the average temperature of the Earth fairly steady during the day and even during the whole year.
• The atmosphere prevents a sudden increase in temperature during daylight hours and slows down the escape of heat into outer space at night.
• The moon, which is almost the same distance from the sun as the Earth, has a temperature range of about -190°C to 110°C and no atmosphere.