What Causes Day And Night

Day time is bright and dazzling, while the night is dark and dim. It’s an almost perfect balance, like yin and yang. The earth rises to the warmth of the sun in the morning and sleeps to the embrace of the cool moon in the night sky. While the sun makes the earth come alive with its passionate heat, the moon makes it relax with its cool romantic touch. The sun has inspired numerous religions over centuries and the moon still doesn’t fail at inspiring romantics and poets across the world. Our earliest memory of the sun is that it rises from the eastern rivers and then drowns itself every evening in the western ones. And it is only when the sun goes that we can see the humble moon. But there is another angle, a rather scientific one that is involved with how the earth witnesses the day and night. What is the cycle that causes day and night on earth and why? Let’s look forward and figure out the answer to this elementary question.  

Day and night on earth are caused by the rotation of earth on its axis. This axis of earth is an imaginary line passing through the north and the south poles. The earth spins on it at an incline. The approximate time taken by earth to complete one rotation on its axis is twenty-four hours. And it is this duration that makes up for a day in our lives.

 

Sun happens to be the only source of light to earth. It not only provides for all the light during the day time, it is also the chief reason for the moon light at night. The positioning of the sun and earth is such that the sun can face only one side of the earth at a time. As such, the side which faces the light experiences day time, while the other side faces the moon and experiences night. This, however, changes in a matter of hours as the earth rotates and the side which experiences night now experiences day and vice versa.

 

As against the popular notion of sun coming out in the east and fading out in the west, the position of the sun is fixed and does not change at all. It is the earth that does all the movement by rev around the sun which creates the illusion. Sun rises in the east due to the earth’s rotational pattern. It rotates from west to east. And later in the noon, when the sun appears approaching south it is actually the earth is rotating southwards. As the earth approaches and gets closer to the west, the sun is believed to have set.

 

A day’s length is measured by the time that the sun takes to set after it rises in the morning. But this rotational nature of earth also causes another interesting development. Since the earth’s rotational axis is rather tilted, hence it is not divided exactly midway through in its night and day; rather the day and night occurrence is such that while the northern hemisphere faces daylight, the southern hemisphere experiences night and vice versa.