What is night? Detailed analysis

The article tells about what night is, why it comes, on what its duration depends and on what planets it does not exist at all.

Ancient times

Night is one of the phenomena through which life began on our planet. After all, if we look at other celestial bodies of our system, that is, on which the day does not change at all. The same Mercury, for example. Because of this, one side of it is red-hot, and the other is covered with eternal darkness. Naturally, there can be no atmosphere and other conditions for life there.

Fear of darkness has been in man since prehistoric times, it was then that much depended on such a phenomenon as the time of the day. The night was not just an indicator of another day, she was carrying a lot of dangers - predators went hunting, in the dark one could not see an enemy or a trap ... Despite the fact that now at night the cities are well lit, the fear of darkness, probably never Will not leave a person. So what is the night?

Definition

Night is a period of time during which, for one or another point of the surface of our planet (or other celestial body), the central star is below the horizon line and, accordingly, does not illuminate it.

The length of the night differs and depends on many factors, such as the latitude, the inclination of the axis of the planet relative to the orbit, the time of the year and the distance from the Sun. Because the inclination of the axis of the planets, including the Earth, differs in relation to the planes of their orbits, the duration of the night period depends on the time of the year.

polar night

Analyzing the question of what night is, one can not help but mention the polar one. From the usual it differs in that in latitudes above the polar, depending on the season, it can not come at all or, conversely, last up to six months.

In the astronomical concept, the night comes at a time when the Sun is 18 degrees below the horizon.

Stars

With all the usual habit of such a phenomenon as darkness at night, it is not inherent in all the planets. For example, in the center of our galaxy because of the huge accumulation of stars, the night, even after the sunset of some local sun, still does not come. Rather, the stars shine so brightly that this time of day is not much different from the day. So now we know what night is.

Ethics

According to the rules of etiquette, night comes at 11 pm, regardless of the latitude or season of the year. And after this time it is considered uncultured to bother people with calls or something else.

What is a day? Morning afternoon Evening Night

Day is called the time, which is approximately equal to the period of revolution of our planet around its axis. It is divided into 24 hours and consists of morning, day, evening and night.

Mythology

Because of the fear of darkness, people at all times have given this time of day a mystical meaning. Even today, when darkness in most countries is not threatened by attack of predators or someone else, city legends are born or passed from person to person, for example, about vampires or other creatures that can not stand the sunlight.