Astronomical phenomena such as the sunset of the sun and the rise of the sun occur every day at different times and only due to the rotation around the sun. In another case, the heavenly luminary would be at a constant zenith, which would deprive the Earth not only of sunrises and sunsets, but life itself on the planet would be impossible.
Sunset and Sunrise
Sunset and sunrise are called time intervals when the upper edge of the Sun is on the same level with the horizon line. The trajectory of the passage of the heavenly body differs depending on from which point on the planet and at what time of the year to watch it. At the equator, the Sun rises perpendicular to the horizon and sets also perpendicularly, regardless of the season.
Where does the sun rise?
Most people know that the sun rises in the east and sets in the west. However, this is nothing more than a generalization. In fact, this happens only 2 days a year - during the spring and autumn equinox. On other days, the sun rises from north to south. Every day, the points at which the sun goes down and the sun rises slightly move. On the day of the summer solstice, it rises to the maximum to the northeast. Every day after this, the star rises a little south. On the day of the autumnal equinox, the Sun rises strictly in the east and sets in the west.
Since ancient times, people tracked the growth and parameters of sunrise and sunset points with great detail. Thus, in antiquity it was possible to navigate in time with the help of jagged mountain peaks along the horizon line or with the help of standing stones built in a special way.
The end and the beginning of daylight
The sunset and sunrise are points of the beginning and end of daylight. It is important to note that both of these phenomena are just short moments. Twilight is the time range during which day becomes night or vice versa. Morning twilight is the time between dawn and sunrise, and evening is the time between sunset and sunset. The duration of twilight actually depends on the location on the planet, as well as on a specific date.
For example, in the Arctic and Antarctic latitudes, a winter night is never completely dark. Sunrise is the moment when the upper edge of the Sun becomes visible above the eastern horizon in the morning. Sunset is the instant when the trailing edge of the Sun ceases to be visible and disappears below the western horizon in the evening.
Daylight hours
The duration of daylight hours, and with it the time of sunset and sunrise, is not a constant. In the northern hemisphere, days are longer in summer and shorter in winter. Daytime also decreases or increases depending on geographic latitude, the higher it is, the shorter the days. As a rule, this is winter time. An interesting fact is that due to the decrease in the Earth's rotation speed , the days become a little longer over time. About 100 years ago, the day was on average 1.7 milliseconds shorter than it is now.
Sunrise - sunset. What is the external difference?
Sunrises and sunsets look different. Is it possible to visually establish these differences if you look at how the sun rises above the horizon, not knowing if the day ends or just begins? So, is there an objective way to distinguish between these two similar phenomena? All twilight time intervals are symmetrical. This means that there is no large optical difference between them.
However, two human factors deny their identity. Closer to sunset, eyes adapted to daylight begin to tire. Gradually, the light disappears, the sky darkens, and a person cannot adapt as quickly as all this happens. Some shades may not be fully appreciated. At dawn, a completely different situation is observed.
Night darkness adjusts vision to a very sharp and clear vision, and every subtle color change in the sky immediately catches your eye. Thus, more flowers are perceived at dawn than in the evening twilight. It is this time, due to limited visibility, that is the most dangerous for drivers, so there is a need for artificial lighting. When dusk sets in, headlights must be turned on.