Chapter 02:Section 01:

Our Planet, Earth

Earth and the Sun• The Earth, the sun, the

planets, and the stars in the sky are all part of a galaxy, or family of stars.– Our galaxy is called the

• Even though the sun is about 93 million miles away, it provides heat and light.

Earth and the Sun

• Earth travels around the sun in a nearly circular

• Earth takes 365 ¼ days, or one year, to complete one

Understanding Days and Nights• Earth circles the

sun• Earth turns on

its • Earth’s

takes about 24 hours.

• As Earth turns towards the sun the sun appears to rise.

• Earth rotates toward the east, so the day starts earlier in the east.

• The time difference is just a few seconds per mile.

• So, governments have divided the world into standard time zones.

Time Zones

Seasons and Latitudes• The axis of Earth is

tilted relative to its orbit.

• At the summer solstice, the Northern Hemisphere is tilted farthest toward the sun.

• At the winter solstice, the Northern Hemisphere is tilted farthest from the sun.

• The area between the Tropic of Cancer and the Tropic of Capricorn are called the low latitudes.

• The areas above the Artic Circle and below the Antarctic Circle are the high latitudes.

• The areas between are the middle latitudes.

Latitudes

• Our galaxy is just one of the billions of galaxies in the universe.

• We call our galaxy the Milky Way because, in a dark night sky, away from city lights its billions of stars look like a trail of spilled milk.

Milky Way

• Orbit is the path one body makes as it circles around another.

• Revolution is circular motion

• Axis is an imaginary line through Earth between the North and South poles, around which Earth turns.

• Rotation is a complete turn