SPACE Chapter 4

6th Grade Science

4.6 Exploring the Solar System

• The sun is the center of our solar system• The solar system is made up of the sun and all

the heavenly bodies that orbit it.• We have eight planets in our solar system

Inner Planets

• Mercury, Venus, Earth, and Mars• These are made mainly of rocks and metals.

Outer Planets

• Jupiter, Saturn, Uranus, and Neptune.• Made of mainly gases, liquids, or ice.

Moons

• Earth has one moon.• Venus and Mercury are the only two planets

that have NO moons.

4.7 Our Earth

• The earth REVOLVES around the sun.• One revolution (trip around the sun) takes

earth 365 ¼ days.• This is called a “solar year”

Rotation page 280

• A rotation is the earth’s spinning on its axis.• One rotation is completed in about 24 hours.

Atmospheric Filter• Our atmosphere acts like a filter to keep earth

a place where humans can live.• The atmosphere is a blanket of air.• It protects us from the sun’s harmful UV rays• It also keeps earth warm because of the

“green house effect.” This is when the heat is trapped on earth because of the atmosphere.

4.8 The Mysterious Moon• The moon is a natural satellite orbiting the

earth.• It’s surface is covered with craters (holes) that

make it look like a sponge.• The moon affects the tides of the oceans on

earth.• There are 8 phases of the moon.

4.9 Smaller Space Travelers• Asteroids are tiny worlds traveling around the

sun.• They range in size from a few 100 miles to a

small house!• Asteroids are usually spherical shape (like

earth)• Made up of metals and rocks

Comets: Icy travelers• Comets are the size of asteroids• They have a bright tail when the come near

the sun• It is made of frozen rock, dust, and ice. It

begins to melt near the sun and this causes the beautiful tail.

• A famous comet is “Halley’s comet”

Meteors: Momentary Intruders• Meteoroids orbit the sun and are much

smaller than asteroids. • If they enter the earth’s atmosphere they are

called a shooting star.• The small ones are burned up as it enters our

atmosphere.• Some large ones cannot be burned up in time

and they hit earth.