LESSON4: EARTH'S MOTION

Rotation

• The circular motion of an object around a fixed line that crosses its center. 

• Axis of Rotation

• The imaginary line that traverses a planet through which it spins around.

• Earth’s Rotation

• Earth’s axial tilt is at an angle of 23.5°, perpendicular to the orbital plane.

• Earth rotates eastward from west to east. 

• One complete rotation of the Earth is equivalent to 24 hours. 

Day and Night

• Caused by Earth’s rotation in which one side is always facing towards the sun and one is facing away from it.  

Time Zones 

• Places on Earth experience different time zones due to Earth’s rotation.

• 360 rotation in 24 hours = 15 meaning every 1 hour, the Earth moves 15 degrees.

Types of Rotation: 

1. Prograde Rotation

• Earth’s counterclockwise direction when viewed from above.

2. Retrograde Rotation

• is the clockwise direction of other planets, like Venus.
  

Zenith

• This is the peak of the sun's path. 

Meridian 

• The imaginary line connecting the poles.

Insolation

• The radiation from the Sun (also known as solar radiation). 

• Insolation is NOT spread evenly on Earth because the Earth is a sphere, the Sun heats equatorial regions more than polar regions.

• The higher the latitude, the lower the insolation. 

Revolution

• The Earth’s motion around the Sun.

• Orbit

• The path on which the revolving object moves on. 

• The Earth has an elliptical orbit (its orbit isn’t a perfect circle, it's more elongated).

• Earth's Revolution

• Earth revolves around the Sun from west to east meaning both its rotation and revolution are eastward. 

• Earth orbits the Sun in approximately 365 days.

Points of Orbit 

(With its elliptical orbit, there are points in which we are either closest or farthest from the sun)

1. Perihelion

• The point in Earth's orbit in which it is closest to the sun. 

2. Aphelion

• The point in Earth’s orbit in which it is farthest to the sun.
  

Seasons

• Caused by the varying amount of insolation received by regions.