What if darkness suddenly appears every night, as if the light switch is off? Are you going to miss the twilight?

The twilight for many people is precious part of the day. It delight them with the change of colors and the gradual darkening of the sky. The twilight of the night encourages many artists to express themselves beautifully.

What causes twilight?

If there was no atmosphere around the earth, complete darkness would suddenly set in at sunset,like turning off the light. This happens when the sun sets below the moon's horizon without an atmosphere.

But on Earth, when the sun disappears from view at night, it continues to illuminate the upper atmosphere for some time. Earth's atmosphere with its many dust particles always reflects sunlight and provides indirect or twilight light to the earth. Therefore, darkness gradually begins as the sun sets over the horizon and less illuminates the atmosphere above. The same phenomenon, but vice versa, occurs in the morning, before dawn. This is also referred to as twilight or, more commonly, dawn.

Not everyone on Earth experiences twilight the same way. This is because its duration varies at different latitudes. For example, in equatorial regions, at lower latitudes, the sun rises and moves almost perpendicular to the horizon. Therefore, it travels "rapidly" below the horizon until its rays touch the upper layers of the Earth's atmosphere. Twilight is therefore very short near the equator.

But in temperate regions, at higher latitudes, the solar path is tilted relative to the horizon. As a result, it takes longer for the sun to "descend" below the horizon to the point where its rays are not reflected back into the atmosphere above. So the twilight is longer there.

The duration of twilight also varies at the same location in different seasons. This is due to the tilt of the Earth's axis, which is why the Sun appears in different positions in the sky at different times of the year, when the Earth revolves around the Sun.

Night twilight intervals

Twilight is sometimes divided into three intervals. First, there is the so-called civil twilight. It begins at sunset and lasts until the sun sets six degrees below the horizon. As long as natural light allows for normal outdoor activities,the first star appears.

Then comes nautical twilight, which continues as the sun sets twelve degrees below the horizon. At this point, only the general outlines of the object can be distinguished, the horizon appears blurry, and even the brightest stars can be seen.

Finally, astronomical twilight ends when the sun reaches eighteen degrees below the horizon. Sunlight is therefore imperceptible and "complete" darkness sets in.

Twilight Phenomena

Twilight sometimes represents a beautiful color display. When the sun is about two degrees below the horizon, a beautiful purple color can appear. This color is a very varied phenomenon, but usually spreads quickly and seems to intensify, giving objects on the ground a purple hue. Violet light lasts until the sun is about six degrees below the horizon. It is said to have been created by scattering sunlight from a layer of turbidity about 60 miles high.

Now it can look like the indescribable blue color is spreading through the air and the ground. This is especially true when the winter landscape is covered with snow. This afterglow in the sky gradually sinks towards the horizon and disappears as the sun approaches 18 degrees below the horizon.

Effect on plants and animals.

The gradual change from day to night gives plants and animals time to adapt. Some plants slowly bend leaves and flowers at sunset, and seem to hide their fragile parts at night. Other plants seem to open up to pick up or inhale something that was missing during the day. They are apparently controlled by a built-in clock, which defines changes of light and darkness.

A similar process takes place in the animal kingdom. Some animals calm down and go to the nest and dig. But the other animals wake up and get ready for their nocturnal activities.

Effect on humans

People may also think that the sunset is a healthy and pleasant part of the day. Provides time to regulate the mind on the approaching night and a pleasant adjustment of the eyes from daylight to darkness. It can soothe the restless mind and often creates an incredible sense of satisfaction. "Only in the evening comes refreshment and relief," says the poet.

Twilight can be an ideal time for meditation. Encourage the person to raise their thoughts to levels higher than those required by their daily activities. It sharpens the deepest thought in the person's mind and helps him to seek his heart.