Why is the atmosphere essential for life?

AcademicBiologyNCERTClass 9

The atmosphere mainly contains air which is a bad conductor of heat. Due to this, the atmosphere keeps the Earth's average temperature fairly balanced during the day and even throughout the year.

The atmosphere prevents the sudden increase in temperature during the daylight hours and during the night. It slows the escape of heat into outer space. In this way, the atmosphere acts as a blanket.

The atmosphere also contains oxygen essential for respiration.

The Earth's atmosphere extends 10,000 km above the surface. After that, space takes over. Not all scientists agree on the atmosphere's upper boundary, although they can agree that most of it is near to Earth's surface, between 8 to 15 km.

Most life on Earth needs oxygen, yet most of Earth's atmosphere isn't oxygen. 78% nitrogen, 21% oxygen, 0.9% argon, and 0.1% other gases make up Earth's atmosphere. Other trace gases include carbon dioxide, methane, water vapor, and neon.

The atmosphere has five temperature-based strata. The troposphere is the layer closest to Earth's surface. At the poles, the troposphere is the thinnest. The troposphere contains 75-80% of the atmosphere's mass. Most of Earth's clouds are in the troposphere, where most of the water vapor, dust, and ash particles exist. Altitude decreases tropospheric temperatures.

The stratosphere is Earth's next stratum. It extends from the tropopause to 50 km. Altitude increases stratospheric temperatures. The stratosphere's ozone layer is made up of a high concentration of ozone. This ozone absorbs some incoming solar energy, safeguarding life on Earth from UV light and causing altitude temperature increases.

Stratopause is the stratosphere's summit. The mesosphere is 85 km (53 mi) above Earth's surface. Altitude reduces mesosphere temperatures. Near the top of the mesosphere, temperatures reach -90°C. Meteors burn up when they fly through the mesosphere, causing "shooting stars."

The thermosphere is 600 km above the mesopause. Temperatures increase with height in the thermosphere. Solar radiation makes the top portions of the thermosphere exceedingly hot, reaching temperatures as high as 2,000 °C.

The exosphere is the layer above outer space. Gas molecules escape into space because the Earth's gravity is so weak.

Layers of gas encircling a planet or astronomical body.

  • Exosphere: the topmost layer of Earth's atmosphere, 550 km (341 miles) above.
  • Mesosphere: Between the stratosphere and thermosphere, 50–80 km above Earth's surface. Space rocks enter Earth's atmosphere. shooting or falling star. The ozone layer absorbs most of the sun's UV rays.
  • Stratosphere: Earth's atmosphere, 10–50 km above the surface.
  • Thermosphere: Earth's atmospheric layer is between 50 and 550 km above the surface.
  • Troposphere: Earth's lowest atmospheric layer, at 16 km high.
Updated on 10-Oct-2022 12:47:42