What is atmosphere? Name its different layers.
Atmosphere is a covering of various gasses that surrounds the plant to a depth of 1000km, or about 600 miles. Without these gases to create an atmosphere, no life would exist and there would be no weather. We would just be another lifeless planet in existence. Scientist have divided the atmosphere into five separate layers – the exosphere, the thermosphere, the mesosphere, the stratosphere and the troposphere. The troposphere is the nearest layer to the surface of the earth and is the only part of the atmosphere where weather happens.
If you look at a photo of the earth taken from a satellite in space you can see the weather systems clearly moving around the atmosphere. The height of the troposphere varies between different areas of the earth. At the equator for example, it stretches to about 20KM, or 12 miles above the surface. At the poles, the layer reaches a height of about 10KM or about six miles.
LAYERS OF ATMOSPHERE :
This is the layer of the atmosphere closest to the Earth's surface, extending up to about 10-15 km above the Earth's surface. It contains 75% of the atmosphere's mass. The troposphere is wider at the equator than at the poles. Temperature and pressure drops as you go higher up the troposphere.
This layer lies directly above the troposphere and is about 35 km deep. It extends from about 15 to 50 km above the Earth's surface. The lower portion of the stratosphere has a nearly constant temperature with height but in the upper portion the temperature increases with altitude because of absorption of sunlight by ozone. This temperature increase with altitude is the opposite of the situation in the troposphere.
Directly above the stratosphere, extending from 50 to 80 km above the Earth's surface, the mesosphere is a cold layer where the temperature generally decreases with increasing altitude. Here in the mesosphere, the atmosphere is very rarefied nevertheless thick enough to slow down meteors hurtling into the atmosphere, where they burn up, leaving fiery trails in the night sky.
The thermosphere extends from 80 km above the Earth's surface to outer space. The temperature is hot and may be as high as thousands of degrees as the few molecules that are present in the thermosphere receive extraordinary large amounts of energy from the Sun. ..............
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