We all know , the world is moving. It takes 23 hours 56 minutes 4 seconds or 24 hours or one day for the earth to rotate from west to east once on its own axis. This rotational motion of the earth is called diurnal motion . The diurnal motion of the earth varies from place to place. Since the earth's surface is not perfectly round, its surface is not uniform everywhere. That is why the rotation velocity of all the places on the earth's surface is not the same. A result of the diurnal motion of the earth occurring day and night. The earth has no light of its own. The earth is illuminated by the light of the sun. Wherever the earth comes in front of the sun for rotation speed, it is illuminated by sunlight. Then there are days in those illuminated places. On the opposite side of the illuminated place, that is, on the opposite side of the earth to the sun, there is darkness. Sunlight does not reach there. In these dark places there is night. As a result of the periodic rotation of the earth, the illuminated side moves towards the dark side and the dark side towards the sun. As a result, day and night change. As the dark places are illuminated, day falls in these places and as the illuminated place becomes dark, night falls in those places. This is happening day and night in phases as a result of the ecliptic motion of the earth. If there was no ecliptic motion, one side of the earth would be in darkness forever and the other side would be illuminated.