World Geography TodayChapter 2 Earth in Space Preview Section 1: The Solar SystemThe Solar System...

World Geography Today Chapter 2

Earth in SpacePreview

Section 1: The Solar System

Section 2: Earth-Sun Relationships

Section 3: The Earth System

Chapter Wrap-Up


Read to Discover

• What is Earth’s position in the solar system?

• How do rotation and revolution affect Earth?



Sun

Mercury

Venus

Earth

Mars

Uranus

Neptune

Jupiter

Saturn



• One of eight planets

• Third planet from the Sun

• Fifth-largest planet

• In elliptical orbit around the Sun


Earth’s Position in the Solar System


• 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.


Rotation and Revolution


Read to Discover

• How does the angle of the Sun’s rays affect the amount of solar energy received at different locations on Earth?

• What are solstices and equinoxes?



• Direct vertical rays of sunlight concentrate solar energy in a smaller area, making more heat.

• Angled rays spread solar energy out, making less heat.

• Earth’s tilt makes direct rays most common near the equator and less common at high latitudes.

• Change in the Earth’s tilt creates seasons.


Angle of the Sun’s Rays

World Geography Today Chapter 1World Geography Today Chapter 2

SolsticeTime twice a year when

Earth’s poles point at their greatest angle toward or

away from the Sun

Equinox

Time twice a year when Earth’s poles are both at a 90° angle from the Sun



• Solstices—About December 21 and June 21

Earth’s poles tilted toward or away from the Sun Longest or shortest days of the year, depending on hemisphere

• Equinoxes—About March 21 and September 22

Earth’s poles not tilted toward or away from the Sun Equal amount of sunlight in both hemispheres


Solstices and Equinoxes


Read to Discover

• What are Earth’s four spheres?

• How is Earth’s environment unique in the solar system?



• Atmosphere—Envelope of gases surrounding Earth; least dense and outermost sphere

• Lithosphere—Solid crust of the planet; forms continents, islands, and ocean floor

• Hydrosphere—Earth’s water; 70 percent of Earth’s surface, including water in liquid, solid, and gaseous forms

• Biosphere—All life-forms; overlaps other three spheres


Earth’s Four Spheres


• No other planet in the solar system has such a complex environment.

• Earth’s environment is the key to human survival and quality of life.


Earth’s Unique Environment

World Geography TodayChapter 2 Earth in Space Preview Section 1: The Solar SystemThe Solar System...

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