The Atmosphere Definition of the Atmosphere The layer of gases surrounding Earth; composed mainly of 78% nitrogen and 21% oxygen, and other gases (water vapor, dust, pollutants, etc.) •Brainpop: •Earth’s atmosphere Layers of the Atmosphere • There are different layers: – Troposphere – Stratosphere – Mesosphere – Thermosphere • Ionosphere • Exosphere • Each layer has a different temperature range. • Different things take place or are found in each layer. Earth Pauses • Between each layer of the atmosphere is a boundary. • These boundaries are called pauses: • At these "pauses," maximum change between the "spheres" occur. – Above the troposphere is the tropopause; – above the stratosphere is the stratopause; – above the mesosphere is the mesopause; and – above the thermosphere is the thermopause. Troposphere • The layer of the atmosphere closest to the earth is the troposphere. • This layer is where weather occurs. • It begins at the surface of the earth and extends out to about 4-12 miles. • Contains 80% of all the mass of the atmosphere and almost all the water vapor. Temperature decreases as you rise. • The temperature of the troposphere decreases with height. • This layer is known as the lower atmosphere. Stratosphere • Stratosphere- Jet planes often fly in the lower levels of this layer because it is above the weather. • This layer contains most of the ozone layer. • People can not breathe in this layer. • Extends to about 30-35 miles above the earth's surface. • Temperature rises within the stratosphere because of the ozone layer but still remains well below freezing. Ozone Layer • Pale, blue gas with a strong odor. O3 • Ozone is extremely important because it is the only gas that absorbs ultraviolet (UV) radiation from the Sun and protects the surface of the Earth and people from the damaging effects of UV rays. • The ozone layer filters out ultra violet light. This protects us from severe burning from sunlight. • Temperature increases as you rise. • 90% of ozone layer in stratosphere; 10% in troposphere Mesosphere • Air is especially thin and molecules are great distances apart. • This is where we see "falling stars" – meteors burning up as they fall to Earth • Temperature decreases as your rise. • About 35 to 50 miles above the surface of the Earth Thermosphere • Layer of the atmosphere which is first exposed to the Sun's radiation and so is first heated by the Sun. • Rises several hundred miles above the earth's surface, from 50 miles up to about 400 miles. • Temperature increases with height and can rise to as high as 3,600Â°F (2000Â°C) but the air would feel cold because the hot molecules are so far apart. • Contains a working station for astronauts. The space shuttle orbits in the thermosphere. • Made up of Ionosphere & exosphere Ionosphere- lower part of thermosphere; contains electrically charged particles known as ions & Inner Van Allen radiation belt; allows the reflection of radio waves for world wide radio communication. Exosphere- Highest layer of atmosphere; farthest layer from earth; limits of this layer are not exactly known. Atoms and molecules escape into space Aurora Borealis a.k.a The Northern Lights Northern Lights or Aurora Borealis • The beautiful blaze of the Northern Lights, or Aurora Borealis, is caused when material thrown off the surface of the sun collides with the atmosphere of the Earth • When the particles collide with the gases in the ionosphere they start to glow, producing an array of colors consists of red, green, blue and violet. • Can see them from the polar regions • Observed in the ionosphere. Click here for animation • The atmosphere is divided into five layers. It is thickest near the surface and thins out with height until it eventually merges with space. • 1) The troposphere is the first layer above the surface and contains half of the Earth's atmosphere. Weather occurs in this layer. 2) Many jet aircrafts fly in the stratosphere because it is very stable. Also, the ozone layer absorbs harmful rays from the Sun. 3) Meteors or rock fragments burn up in the mesosphere. 4) The thermosphere is a layer with auroras. It is also where the space shuttle orbits. 5) The atmosphere merges into space in the extremely thin exosphere. This is the upper limit of our atmosphere.
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