The phenomenon of darkness, or the absence of light, is caused by the rotation of the Earth on its axis as it orbits the sun. The Earth rotates on its axis in a counterclockwise direction, causing different parts of the planet to experience periods of daylight and darkness.

As the Earth rotates, the position of the sun in the sky changes, casting shadows on different parts of the planet. When the sun is directly overhead, an area receives the most direct sunlight, resulting in bright daylight. When the sun is below the horizon, an area is in the shadow of the Earth, resulting in darkness.

The length of the day and night, or the amount of time an area experiences daylight and darkness, varies depending on the location on the Earth’s surface. This is due to the tilt of the Earth’s axis, which is tilted at an angle of 23.5 degrees relative to the plane of its orbit around the sun.

During the summer months, the North Pole is tilted towards the sun, causing the Northern Hemisphere to experience longer periods of daylight. Conversely, during the winter months, the North Pole is tilted away from the sun, causing the Northern Hemisphere to experience longer periods of darkness. The opposite is true for the Southern Hemisphere, which experiences longer periods of daylight in the winter and longer periods of darkness in the summer.

In conclusion, the phenomenon of darkness, or the absence of light, is caused by the rotation of the Earth on its axis as it orbits the sun. The length of the day and night, or the amount of time an area experiences daylight and darkness, varies depending on the location on the Earth’s surface due to the tilt of the Earth’s axis.