• Earth, along with the other planets, is believed to have been born 4.5 billion years ago as a solidified cloud of dust and gases left over from the creation of the Sun. • For perhaps 500 million years, the interior of Earth stayed solid and relatively cool, perhaps 2,000°F. • The main ingredients were iron and silicates, with small amounts of other elements, some of them radioactive. • As millions of years passed, energy released by radioactive decay—mostly of uranium, thorium, and potassium—gradually heated Earth, melting some of its constituents. • The iron melted before the silicates, and, being heavier, sank toward the center. • This forced up the silicates that it found there. • After many years, the iron reached the center, almost 4,000 mi deep, and began to accumulate. No eyes were around at that time to view the turmoil that must have taken place on the face of Earth—gigantic heaves and bubblings on the surface, exploding volcanoes, and flowing lava covering everything in sight. • Finally, the iron in the center accumulated as the core. Around it, a thin but fairly stable crust of solid rock formed as Earth cooled. • Depressions in the crust were natural basins in which water, rising from the interior of the planet through volcanoes and fissures, collected to form the oceans. Slowly, Earth acquired its present appearance.

1. Origin of Earth,
Temperature on
Earth, Sun Earth
Relationship
and Atmosphere
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Shalini Pandey 1

2. ORIGIN OF EARTH
■ Earth, along with the other planets, is believed to have
been born 4.5 billion years ago as a solidified cloud of
dust and gases left over from the creation of the Sun.
■ For perhaps 500 million years, the interior of Earth
stayed solid and relatively cool, perhaps 2,000°F.
■ The main ingredients were iron and silicates, with
small amounts of other elements, some of them
radioactive.
■ As millions of years passed, energy released by
radioactive decay—mostly of uranium, thorium, and
potassium—gradually heated Earth, melting some of
its constituents.5/20/2016 Shalini Pandey 2

3. ORIGIN OF EARTH
■ After many years, the iron reached the centre, almost
4,000 miles deep, and began to accumulate. the turmoil
that taken place on the face of Earth—bubbling on the
surface, exploding volcanoes, and flowing lava covering
everything insight.
■ Finally, the iron in the centre accumulated as the core.
Around it, a thin but fairly stable crust of solid rock formed
as Earth cooled.
■ Depressions in the crust were natural basins in which
water, rising from the interior of the planet through
volcanoes and fissures, collected to form the oceans.
Slowly, Earth acquired its present appearance.
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4. TEMPERATURE ON
EARTH■ Planet Earth can support life. The planet is not too close or too far
away from the sun. It lies in a "Goldilocks zone" that is just right —
not too hot, not too cold.
■ The distance from Earth to the sun is one of the most important
factors in making Earth habitable.
■ The average temperature on Earth is about 61 degrees F (16 C).
But temperatures vary greatly around the world depending on the
time of year, ocean and wind currents and weather conditions.
■ Summers tend to be warmer and winters colder. Also, temperatures
tend to be higher near the equator and lower near the poles.
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5. SUN EARTH
RELATIONSHIP■ Figure 1 below shows that the orbit of the Earth about the
sun is not circular. The path is elongated or elliptical. This
means that the distance from the Earth to the sun varies
through the year. Two special events are depicted in the
diagram. Aphelion (July 4) is when the Earth is as far away
from the sun as it ever gets. Perihelion (Jan. 3) is when the
Earth is as close to the sun as it ever gets.
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6. 5/20/2016 Shalini Pandey 6
■ Sun is the main source of
energy.
■ The spinning of the Earth
about its axis is called
Rotation.
■ One rotation takes about
24 hours or 1 day.
■ It rotate from west to
east.
■ It revolve around a sun
and takes 365 days s
hours and 48 minutes.
■ Earth is 23 degree 30
minute tilted on its axis
and thus make 66 degree
30 minute angle.

7. ATMOSPHERE
■ The atmosphere of is the
layer of gases that
surrounds the planet Earth
and is retained by Earth's
gravity.
■ The atmosphere protects
life on Earth by absorbing
ultraviolet solar radiation,
warming the surface
through heat retention and
reducing temperature
extremes between day and
night.
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8. Composition of
atmosphere
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■ Nitrogen - 78.09%
■ Oxygen - 20.95%
■ Argon - 0.93%
■ carbon dioxide -
0.039%
■ small amounts of
other gases
■ water vapor - 2%

9. Layers of Atmosphere
■ Troposphere
■ Stratosphere
■ Mesosphere
■ Thermosphere
■ Ionosphere
■ Exosphere
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10. Troposphere
■ The lowest region in the
Earth's atmosphere
■ Goes from ground (or water)
level up to about 11 miles (17
kilo meters) high
■ The densest part of the
atmosphere
■ All weather and clouds occur
■ Temperature generally
decreases as altitude
increases
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11. Stratosphere
■ Starts just above the
troposphere and extends
to 50 kilo meters high
■ characterized by a slight
temperature increase with
altitude and the absence
of clouds.
■ The ozone layer, which
absorbs and scatters the
solar ultraviolet radiation,
is in this layer.
■ Provides ideal flying
condition for large jet
plane.
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12. Mesosphere
■ The mesosphere starts
just above the
stratosphere and
extends to 85 kilo
meters high.
■ Meteors burn up in this
layer.
■ The mesosphere is
characterized by
temperatures that
quickly decrease as
height increases.
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13. Thermosphere
■ The thermosphere
starts just above the
mesosphere and
extends to 600 kilo
meters high.
■ Aurora and satellites
occur in this layer.
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14. Ionosphere
■ an abundant layer of electrons and ionized atoms and molecules
that stretches from about 48 kilo meters above the surface to the
edge of space at about 965 km, overlapping into the mesosphere
and thermosphere.
■ This dynamic region grows and shrinks based on solar
conditions and divides further into the sub-regions: D, E and F;
based on what wavelength of solar radiation is absorbed.
■ The ionosphere is a critical link in the chain of Sun-Earth
interactions. This region is what makes radio communications
possible. Auroras occur in the ionosphere.
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15. Exosphere
■ the outermost layer of the
Earth's atmosphere.
■ The exosphere goes from
about 640 km high to about
1,280 km.
■ The lower boundary of the
exosphere is called the
critical level of escape,
where atmospheric
pressure is very low (the
gas atoms are very widely
spaced) and the
temperature is very low.
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