Earth in Space

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Earth in Space

• Preview
• Section 1 The Solar System
• Section 2 Earth-Sun Relationships
• Section 3 The Earth System
• Chapter Wrap-Up

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Section 1 The Solar System

• Read to Discover
• What is Earths position in the solar system?
• How do rotation and revolution affect Earth?

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Section 1 The Solar System
Question What planets and stars make up our
solar system?
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Section 1 The Solar System
Jupiter
Sun
Neptune
Saturn
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Section 1 The Solar System
Earths Position in the Solar System

• One of eight planets
• Third planet from the Sun
• Fifth-largest planet
• In elliptical orbit around the Sun

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Section 1 The Solar System
Rotation and Revolution

• Rotation and revolution affect the amount of
  solar energy Earth receives at different
  locations.
• Rotation of Earth on its axis produces day and
  night.
• Revolution around the Sun takes one year.
• Revolution and the tilt of Earth on its axis
  determine seasons.

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Section 2 Earth-Sun Relationships

• Read to Discover
• How does the angle of the Suns rays affect the
  amount of solar energy received at different
  locations on Earth?
• What are solstices and equinoxes?

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Section 2 Earth-Sun Relationships
Angle of the Suns Rays

• Direct vertical rays of sunlight concentrate
  solar energy in a smaller area, making more heat.
• Angled rays spread solar energy out, making less
  heat.
• Earths tilt makes direct rays most common near
  the equator and less common at high latitudes.
• Change in the Earths tilt creates seasons.

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Section 2 Earth-Sun Relationships
Question What are the Earths solstices and
equinoxes?
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Section 2 Earth-Sun Relationships
Time twice a year when Earths poles point at
their greatest angle toward or away from the Sun
Time twice a year when Earths poles are both at
a 90 angle from the Sun
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Section 2 Earth-Sun Relationships
Solstices and Equinoxes

• SolsticesAbout December 21 and June 21
• Earths poles tilted toward or away from the Sun
• Longest or shortest days of the year, depending
  on
• hemisphere
• EquinoxesAbout March 21 and September 2
• Earths poles not tilted toward or away from the
  Sun
• Equal amount of sunlight in both hemispheres

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Section 3 The Earth System

• Read to Discover
• What are Earths four spheres?
• How is Earths environment unique in the solar
  system?

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Section 3 The Earth System
Question What are the four parts of the Earth
system?
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Section 3 The Earth System
Earths Four Spheres

• AtmosphereEnvelope of gases surrounding Earth
  least dense and outermost sphere
• LithosphereSolid crust of the planet forms
  continents, islands, and ocean floor
• HydrosphereEarths water 70 percent of Earths
  surface, including water in liquid, solid, and
  gaseous forms
• BiosphereAll life-forms overlaps other three
  spheres

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Section 3 The Earth System
Earths Unique Environment

• No other planet in the solar system has such a
  complex environment.
• Earths environment is the key to human survival
  and quality of life.

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Chapter Wrap-Up Understanding the Main Ideas

1. What term describes Earths shape?
2. How long does it take Earth to make one complete
   rotation on its axis? One complete revolution
   around the Sun?
3. When do the Suns most direct rays strike in the
   Northern Hemisphere? What effect does this have
   on temperatures there?
4. During the solstices, where do Earths poles
   point in relation to the Sun?
5. What is the Earth system?