Change of Day/Night
Frequently required for everyday life term nychthemeron serves for description of the time cycle during which the Sun rising up from the Orient transits across the sky sets onto the West. The end of luminary travelling means coming night on the Earth. Over a period of it the Sun-star is passing the other side of our planet and ready to appear on the East again.
Time and Clock
With 24 hours realizing above mentioned transitions which is determined a day; an hour is 60 minutes and in a minute numbers 60 seconds. Corresponding to these facts the nychthemeron is 24 h or 1440 m or even if to count in seconds: 86400 s. In the name of comfort people use 2 formats.
So, talking about the solar time ways to perceive during centuries would be logical to pay attention on the time-counting convention.
The 12-hour clock has significant of convention to count time before the midday from 00.00 till 11.59 (a.m.) and the afternoon from 12.00 till 11.59 (p.m.). The United Kingdom of Great Britain and Northern Ireland, Ireland, France, Greece, Turkey, Australia, Canada, the United States of America and Philippines use 12-hour clock.
24-hour clock literally means from 00.00 till 23.59 widespread in Russia and other countries.
How is physically realized the terrestrial day/night shift?
Apart from the Earth rotation around the Sun, the globe makes vertiginous motions about its own axis. The complete turn results in 24 hours, so called day or nychthemeron officially.
Despite of it people do not feel these movements and can only be proved observing the motion on the basis of visible change of the Sun position, stars according to the globe.
The day is divided on the next part for convenience:
- Morning starts with the sky daybreak from the East and the sunrise on horizon.
- Day is characterised according to the Sun as it movement from the East to the West.
- Evening is the sunset on the West and tender fading colours of the day.
- Night is the darkest time of nychthemeron when the Sun passes from the other side of our planet.
Due to the fact that the Earth is rich by the presents of continents which are situated by the both sides of the globe the time for day and night is not the same in the different parts of the terrestrial planet. New-York night is exemplified London morning, Moscow midday is evening in Petropavlovsk-Kamchatsky.
So many centuries been under a delusion it has been recently considered that the movement of the globe around it axis is steadily even. The scientists overcome this myth and count inaccuracies. The unevenness is connected with a little tramping of the globe that has a scientific nomination of a nutation. The nutations are so miserable, numbering less than 0.001 s; and they are not influenced on the calendar preciseness.
The longitude of the nychthemeron is a constant value but to say the same about the parts of it would be a mistake. How long would be day or night depends of the season, the Earth declination and the movement of the Sun along to ellipsoid trajectory. So, the daylight period is considerably longer than in winter and vice versa.
Even the geographical position of the place should be count in the aspect of the day to night shift, for example, in Crimea the evenings fall abruptly, nights are southern deep dark but June in Saints Petersburg is remarkable with it white nights that has a physical explanation in the view of the sunset realizing not so far from horizon line and the nocturne time for this reason seems so light.
The inequality of nychthemeron looks and perceives in different manner. The background of it is hidden in biological rhythms which a human lives (such as daily wakefulness and night sleeping). Perceptions of colour contrasts, even mood are linked to it too. Doubtable that you have never noticed the rise of the energy in the morning which spends for studying and working but the evening brings tiredness, feeling like squeezed if the day brought you a lot of deals.
The stages of the nychthemeron have been drawing by famous Russian artist Nikolay Petrovich Krymov in his learning landscape under the name “The change in the landscape of relations in tone and colour at different times of day”.
In the landscape is depicted a simple motif. There are a lithe forest house, diagonal leading pass, which enriches the picture with volume, field and sky. Times to time people were passing and it gave the picturesque character to the canvas. The landscape was drawn 9 times during a day, so, the artist could obviously prove the modifications of the nature, colours on dawn, in the morning and than in the evening when the sun goes done. It is realized with the shadow shifting.
The rhythm of the changes is in tune with the vegetal and animal kingdom of the nature. In the morning the plants expand themselves and in the evening the flowers buds are getting close.
Life fixed on round the clock
The organic modifications are in harmony with the human world. The typical timetables studying, working and entertainment hours even the radio and TV programmes, etc. are under scrupulous control of the nychthemeron which people use to call biological rhythms dependence.