Download The Exosphere

The Exosphere
The highest layer of the atmosphere is called the exosphere. The word
“exosphere” means: Greek: "outside sphere.” The exosphere is the region where
atoms and molecules escape from the atmosphere into outer space. There is no real
end to the exosphere – it just fades off into space. The main gases in the
exosphere are the lightest gases, such as hydrogen and helium. Most satellites,
including cable TV satellites, cell phone satellites and the ones that broadcast XM
radio orbit the earth in the exosphere. The International Space Station, however,
orbits lower in the thermosphere!
The Thermosphere
The thermosphere starts just above the mesosphere and extends to 600
kilometers (372 miles) high. It can get VERY hot in the thermosphere! In fact,
temperatures can reach as high as 3,600°F (2000°C) near the top of this layer!
Wow!!! In the thermosphere, the sky no longer appears blue. Instead, it is dark
like the night sky — even during the day! You can see stars, but the stars do not
twinkle, because there is so little air.
The thermosphere also includes a very special region of the Earth's atmosphere
called the ionosphere. The ionosphere is the region of the atmosphere that is filled
with charged particles! In fact, the word ionosphere means ionizing sphere. The
molecules of gas in the ionosphere absorb energy from the sun, and become
excited or “charged”. Radio waves bounce off of the charged particles in the
ionosphere as they travel back and forth between places on Earth’s surface! So
whenever you listen to AM or FM radio, you are using the ionosphere to get your
music!
Have you seen the aurora borealis (the Northern Lights.) They occur when
powerful magnetic energy given off by the sun (called the solar wind) blasts the
Earth’s protective magnetic field. The Earth’s magnetic field is like a force field that
protects us from the solar wind, but it is very weak at the North and South Pole.
Sometimes this energy breaks into Earth’s atmosphere and reacts with the charged
particles in the ionosphere, causing them to glow! Green, white and pink waves of
light can dance across the sky for hours
The Mesosphere
Mesosphere literally means: “middle sphere” The mesosphere, starts just
above the stratosphere and extends to 85 kilometers (53 miles) high. In the
mesosphere, temperature decreases from about 5°F (-15°C) to as low as -184°F (120°C). Even though the mesosphere is VERY cold, METEORS burn up the
mesosphere due to vaporization, leaving fiery trails in the night sky that we call
shooting stars.
The Stratosphere
Stratosphere begins around 10 km (6 miles) and extends until about 50 km
(31 miles). As you move up through the stratosphere, the temperature rises
from an average -76°F (-60°C) to a maximum of about 5°F (-15°C).
a. This OZONE layer is found in the stratosphere around an altitude of 25
kilometers.
b. The OZONE or O3 molecules absorb dangerous UV light from the sun,
which heats the air around them.
Most commercial airplanes (Delta, Frontier, etc.) fly in the upper troposphere
and lower stratosphere around 10 km (35,000 feet). The jets fly in the “jet
stream” which is strong directional winds.
The Troposphere
Troposphere literally means: Greek “change” due to the weather.
The troposphere begins at the Earth's surface and extends up about 10 km (6
miles) high. The temperature in the troposphere goes down (gets colder) as you go
higher, from 62°F (17°C) to as cold as -60°F (-51°C)! The troposphere is the most
active part of the atmosphere, and the air is constantly moving.
Almost all weather occurs in the Earth's troposphere due to the constant movement
of air and heat. The troposphere is the most dense layer of the atmosphere –
about 72% of the total mass of the atmosphere is found in the troposphere.
**Fact: Most of the SUN’s heat is LOST in space.
What is altitude? The height above sea level (measured in feet or kilometers)
What is air pressure? Measure of the force with which air molecules push on a
surface measure with a barometer.
How does altitude and air pressure relate? The higher (go up towards space) the
altitude the less (lower) air pressure.
List 3 man-made causes of air pollution: burning fossil fuels, driving gas
cars/boats/airplanes, starting forest fires, burning wood for fireplace, running air
conditioning too long, spraying aerosols, pesticides, factory pollution
List 3 natural causes of air pollution: volcanic gasses, sulfur from geysers, forest
fires started by lightening or drought, animal “gas” methane, dust storms,
Draw a pie graph of the Atmosphere Gasses- label and write the %
Oxygen 21%
Nitrogen 78%
Other gasses (argon, helium) 1%