Unit 7 (Part 1)

is a medium sized star and the only star in our solar system.

is a terrestrial planet made of rock and water

is a natural satellite of Earth

is the accepted belief of how the moon formed. When a Mars sized asteroid struck Earth forming a ring of debris around Earth which eventually pulled together by the force of gravity to create the Moon.

The spinning of Earth on its axis

the time required for Earth to rotate once on its axis

The movement of one object around a central object. (One revolution equals a year)

The Earth revolves one time around the Sun every 365.25 days which is equal to a

To make up for the .25 days every four years an extra day (February 29th) is added to the calendar and is called a

roughly the amount of time required for the moon to orbit the earth once