How long does it take the Earth to move from Point A to Point C?

Explanation:

As you know that the earth has two types of motions,

namely rotation and revolution. Rotation is the

movement of the earth on its axis. The movement of

the earth around the sun in a fixed path or orbit is

called Revolution.

The axis of the earth which is an imaginary line,

makes an angle of 66½° with its orbital plane. The

plane formed by the orbit is known as the orbital plane.

The earth receives light from the sun. Due to the

spherical shape of the earth, only half of it gets light

from the sun at a time (Figure 3.2). The portion facing

the sun experiences day while the other half away from

the sun experiences night. The circle that divides the

day from night on the globe is called the circle of

illumination. This circle does not coincide with the

axis as you see in the Figure 3.2. The earth takes about

24 hours to complete one rotation around its axis.

The period of rotation is known as the earthday. This is

the daily motion of the earth.

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MOTIONS OF THE EARTH 19

Figure 3.3 : Revolution of the Earth and Seasons

What would happen if the earth did not rotate? The

portion of the earth facing the sun would always

experience day, thus bringing continuous warmth to

the region. The other half would remain in darkness

and be freezing cold all the time. Life would not have

been possible in such extreme conditions.

50% lit on the left side