Noon is the time when the position of the sun in the sky is the highest

Observing during the day the movement of the sun in the sky, a man has tried to find an explanation from ancient times. Dependence on the luminary in the definition of time, in the organization of economic and everyday life generated an attitude towards him as a deity. Myths about the chariot of chariots that make the daily journey across the sky are reflected in the cultures of many peoples. It is logical that the culmination of this procession - the moment when the position of the sun in the sky is the highest, formed the basis of time counting.

Noon

The fact that the Sun does not revolve around the Earth, but on the contrary, became finally understood only by the middle of the 16th century. And one of the people who expressed this idea (Copernicus), was so sure that it contradicts the obvious - that one can observe daily, that he preceded his publication about the heliocentric system with the words about its obvious absurdity.

Now the schoolboy knows that in fact the motion of the solar disk in the sky is the result of the rotation of the Earth around its axis, that one complete revolution our planet makes in a day that the position of the sun above the horizon at a particular time depends not only on the angle of rotation to the luminary. It affects the position occupied by the Earth in the course of its annual circulation around the Sun. In the winter in the northern hemisphere, our luminary rises at noon lower than in the summer.

Zenith

In order to accurately determine when the position of the sun in the sky is the highest, it is important to understand how this position is measured. If the highest point of the center of the solar disk at noon is located exactly above the head (then a pole stuck into the ground strictly vertically, casts a zero shadow), so the observer is at the equator.

In the Northern Hemisphere, the point of zenith, the largest angle of inclination of the sun with respect to the horizon during the day, or the position of the sun at noon, shifts to the north, in the Southern Hemisphere it moves southward for a year. The main reason for the annual change in the height of the sun above the horizon at noon is the slope of the axis of rotation of the globe to the plane of the orbit. It is constant and equal to 23.5 °.

Winter and Summer

This inclination also explains the change of seasons on our planet. The reference points in the onset of astronomical winter or summer are the solstice points. In the Northern Hemisphere, the summer solstice day is June 21 and 22. It is on this day that the sun is above all in the sky. The angle of the sun's rays on the surface of the planet is such that it heats up the best. Gradually heated large masses of water and land and increases the temperature of the air. At that time the northern hemisphere is facing the sun.

In winter, on December 21 and 22, north of the equator at noon, when the position of the sun in the sky is the highest, it rises above the horizon to the minimum height, if we take the change in this indicator during the year. Our area of the earth's surface is thus deployed away from the main star of the solar system, receiving the least amount of beneficial heat. In the southern hemisphere, everything is exactly the opposite.

True (astronomical) time

The appearance of such units of time as the year, month and day is associated with astronomical observations and is directly dependent on the interaction between the only inhabited planet and the central star. The division into hours, minutes and seconds is arbitrary. The main factor for the appearance of such numbers is the sex-decimal number system, which was traditional for Ancient Babylon - exactly from there the modern units of time measurement originate.

The period that passes between the moments when the position of the sun in the sky is the highest - what is called the day - is unstable for a year. The fluctuation of this difference reaches 30 minutes and is explained by the elliptical shape of the orbit along which the Earth moves around the luminary. If the real time were used in practice, it would be necessary to create a clock with an uneven course. Technically, now it is possible, but it is in our time, when high accuracy of synchronization of events occurring in different regions of the planet is required, such a system seems particularly impractical.

Average time

In order to level the annual difference in the duration of astronomical days, astronomers have introduced the so-called "average Sun". This purely theoretical concept denotes the point determining the position of our luminary in the firmament, the movement of which is 365 days evenly. Twice a year its position coincides with the center of the present Sun. This occurs in the days of the spring and autumn equinox.

The introduction of the "average Sun" led to the use of a more convenient in practice middle time, otherwise called civil. So, on a day different from the days of the equinox, the twelfth stroke of the clock at noon does not at all mean the time of the day when the position of the sun is the highest. To calculate a similar moment with an accuracy of fractions of a second, use the "time equation", which contains data derived from the geographical coordinates of a particular location.