One of the vast numbers of systems that contains stars, nebulae, space debris and star clusters that make up the universe.

They are held together by their own gravitational fields, and they are the major building blocks of the universe.

We are in the Milky Way Galaxy. 

The distance light travels in a year in a vacuum, approximately 5.88 trillion miles.

The speed of light is 186,000 miles per second.

In space, distances are so vast that they are measured in light years. 

(1) A manmade object or vehicle made to orbit the earth, or

(2) A celestial body orbiting another of larger size. 

The sun and everything that orbits around it.

A complete turn around an axis or point.

One trip around the sun is called a revolution. 

The force that pushes objects in a curved motion away from the center of the curve.

As planets travel around the sun, centrifugal force pushes the planets away, thus balancing the gravitational pull of the sun. 

An imaginary pole that passes through the earth connecting the North and South Poles.

The earth spins on its axis, which causes  night and day because only half the earth faces the sun at a time. 

The zone of transition between light and dark around a sphere.

For example, if the earth stopped rotating on its axis, one side would always face the sun (hot and light), and one side would always face away from the sun (freezing and dark).  The only part of Earth that would be habitable would be the thin zone of transition between light and dark areas. 

Planets composed of rock material similar to earth.  They have very few moons, and are small and dense.

Mercury, Venus, Earth & Mars 

Terra is the Latin name for earth. 

Planets composed of frozen gasses.  They are much larger than terrestrial planets, and are much less dense.  They each have several moons and distinctive rings of particles.

Jupiter, Saturn, Uranus, Neptune 

CONTINENT

List from largest to smallest. 

One of the seven principle land masses on earth.

 Asia, Africa, North America, South America, Antarctica, Europe, Australia

ISLAND

What are the three largest islands on Earth? 

Any land mass smaller than a continent that is completely surrounded by water.

The three largest islands on Earth in order of size are Greenland, New Guinea, and Borneo. 

The body of salt water that covers over 70% of the Earth's surface and is divided into five primary oceans.

Atlantic, Pacific, Arctic, Antarctic and Indian Oceans