Life on our planet depends on the amount ofsunshine and heat. It is terrible to imagine even for a moment what would have happened if there had not been such a star in the sky as the sun. Every blade of grass, every leaf, every flower needs warmth and light, like people in the air.
Количество солнечного света и тепла, которое enters the earth's surface, is directly proportional to the angle of incidence of the rays. The sun's rays can fall to Earth at an angle from 0 to 90 degrees. The angle of the rays on the earth is different, because our planet has the shape of a ball. The bigger it is, the brighter and warmer it is.
Thus, if the beam goes at an angle of 0degrees, it only slides along the surface of the earth without heating it. This angle of incidence occurs at the North and South Poles, beyond the Arctic Circle. At right angles, the sun's rays fall on the equator and on the surface between the Southern and Northern Tropics.
If the angle of sunlight on the ground is direct, it means that the sun is at its zenith.
Thus, the angle of incidence of rays on the surfacethe land and the height of the sun above the horizon are equal to each other. They depend on the geographical latitude. The closer to zero latitude, the closer the angle of incidence of rays to 90 degrees, the higher the sun is above the horizon, the warmer and lighter.
The height of the sun above the horizon is notconstant value. On the contrary, it always changes. The reason for this lies in the continuous movement of the planet Earth around the star Sun, as well as the rotation of the planet Earth around its own axis. As a result, day is replaced by night, and the seasons of each other.
The territory between the tropics receives the most heat and light, here day and night are almost equal to each other in duration, and the sun is at its zenith 2 times a year.
The surface of the Arctic Circle receives all the less heat and light, there are such concepts as polar day and night, which last about six months.
Выделены 4 основные астрологические даты, которые determines the height of the sun above the horizon. September 23 and March 21 are the days of the autumn and spring equinoxes. This means that the height of the sun above the horizon in September and March these days is 90 degrees.
The southern and northern hemispheres are illuminated by the sunthe same, and the longitude of the night is equal to the longitude of the day. When an astrological autumn comes in the Northern Hemisphere, in the Southern, on the contrary, spring. The same can be said about winter and summer. If in the southern hemisphere winter, then in the northern - summer.
22 июня и 22 декабря – дни летнего и зимнего solstice. December 22 is the shortest day and the longest night in the Northern Hemisphere, and the winter sun is at the lowest altitude above the horizon for the entire year.
Above latitude 66.5 degrees the sun is underhorizon and does not rise. This phenomenon, when the winter sun does not rise to the horizon, is called the polar night. The shortest night is at a latitude of 67 degrees and lasts only 2 days, and the longest happens at the poles and lasts 6 months!
December is from the whole year the month whenthe longest nights in the northern hemisphere. People in Central Russia wake up to work in the dark and also return at night. This is a difficult month for many, as the lack of sunlight affects the physical and moral condition of people. For this reason, depression may even develop.
В Москве в 2016 г.Sunrise on December 1st will be at 08.33. In this case, the longitude of the day will be 7 hours and 29 minutes. Sunset over the horizon will be very early, at 16.03. The night will be 16 hours 31 minutes. Thus, it turns out that the longitude of the night is 2 times more than the longitude of the day!
This year's winter solstice - 21December The shortest day will last exactly 7 hours. Then the same situation will last 2 days. And from December 24, the day will go to profit slowly but surely.
On average, one minute of light time will be added per day. At the end of the month, sunrise in December will be exactly at 9 o'clock, which is 27 minutes later than December 1st
June 22 is the summer solstice.Everything happens exactly the opposite. For the whole year on this date, the longest day in duration and the shortest night. This is with regards to the Northern Hemisphere.
In the South all the way around.Interesting natural phenomena are associated with this day. Beyond the Arctic Circle the polar day comes, the sun does not set at the North Pole for 6 months. Mysterious white nights begin in St. Petersburg in June. They last from about mid-June for two to three weeks.
All these 4 astrological dates can vary by 1-2 days, as the solar year does not always coincide with the calendar year. Shifts also occur in leap years.
The sun is one of the most importantclimate factors. Depending on how the height of the sun changes above the horizon above a specific part of the earth's surface, climatic conditions and seasons change.
Например, на Крайнем Севере лучи солнца падают at a very small angle and only glide along the surface of the earth, not heating it at all. Under the condition of this factor, the climate here is extremely harsh, there is permafrost, cold winters with chilling winds and snow.
Чем больше высота солнца над горизонтом, тем warmer climate. For example, at the equator it is unusually hot, tropical. Seasonal fluctuations are also practically not felt in the equatorial region, in these areas eternal summer.
As they say, everything ingenious is simple.So it is here. The device for measuring the height of the sun above the horizon is elementary simple. It is a horizontal surface with a pole in the middle of a length of 1 meter. On a sunny day at noon, the pole casts the shortest shadow. With the help of this shortest shadow and calculated and measured. It is necessary to measure the angle between the end of the shadow and the line connecting the end of the pole with the end of the shadow. This angle will be the angle of the sun above the horizon. This device is called the gnomon.
Gnomon is an ancient astrological tool. There are other instruments for measuring the height of the sun above the horizon, such as a sextant, quadrant, astrolabe.
