One of the planets that spin and travel around the Sun
A very tiny part of the universe, but home to many forms of life
Earth's motion
Moves at a constant speed
Follows a counterclockwise direction
Rotates and travels around the Sun
Moves through the Milky Way galaxy with the rest of the planets in the Solar System
Earth's rotation
1. Spins on its axis at a regular rate once every 24 hours
2. Direction of rotation is from west to east or counterclockwise
Earth's rotation
Causes day and night
Earth's revolution
Movement of the Earth around the Sun
Takes the Earth a year, or 365 1/4 days to revolve around the Sun
Gregorian calendar uses 365 days, so a leap year is used every four years to add one day to the end of February to keep the calendar in sync with the revolution of the Earth
Earth's orbit
Elliptical shape
Reason why the Earth is sometimes far from or close to the Sun
Earth's revolution and tilt of its axis
Causes the four seasons (summer, autumn, winter, spring)
Seasons
1. Summer begins on June 21 or 22 when the North Pole is tilted towards the Sun
2. Winter begins on December 21 or 22 when the North Pole is tilted away from the Sun
3. Spring equinox on March 21 when day and night are of equal length
4. Autumnal equinox on September 23 when day and night are of equal length
