الأحد، 21 ديسمبر، 2014

Winter Solstice on December 21

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  Sunrise late to the sun and sunset Packer her, long and short day and night. This is what is actually happening since the beginning of the month of December of each year to the day that comes from 21 to announce this astronomical phenomenon annual so-called "winter solstice" in the northern hemisphere. Coup happens (whether it was summer or winter) at the same moment in the same parts of the globe. In 2012, corresponding to 21 December and at 14:12 GMT (11:12 UTC) Winter Solstice occurs.

  Night and day for the moment Winter Solstice on 21 December





      Try to follow the ancient path of the sun when you cut the sky Fajlsoaely that the length of the day and the sunset and sunrise sites all changed in a systematic way during the year. As a result, they built them Khjarh Stonehenge, which was built in the prehistoric age for the purpose of follow-up behavior of the Sun on an annual basis landmarks. But in the present age, and thanks to scientific and technological progress, it became possible to astronomical phenomena from outer space control. Today we look at the Winter Solstice on an astronomical event that results from Milan and the Earth's axis of rotation around the sun. It is known that the Earth does not revolve around themselves completely vertical, but deviates spin axis by 23.5 degrees, so the amount of energy it receives the earth from the sun are rotating at the northern and southern halves of them. It is common mistakes to say that the summer and winter as a result of growing up near or after the Earth from the sun, but the scientific true that summer and winter growing up because of the deviation of the Earth's rotation axis around itself by 23.5 degrees.


   Sunlight during the Winter Solstice. The Arctic in the dark for 24 hours while serving the South Pole during the day in his day.

      At the Winter Solstice, the sun's rays are completely perpendicular to the Tropic of Capricorn which is an imaginary line falls below the equator 23.5 degrees. The sun is completely vertical overhead at noon, and the areas in the northern hemisphere have their day shorter than 12 hours, while areas in the southern half of them have their day more than 12 hours a day. It is noted in the northern hemisphere delayed dawn and sunset offers in addition to the decrease in the bow, which cut its sky, which means the sun is low in the sky to appear during the afternoon and thus the solar shade is the longest in time throughout the year.

The deviation of the Earth's axis 23.5 degrees causes the phenomenon of Winter Solstice.

      The fact that more delays for sunrise and sunset for more progress and its relationship with the winter solstice:

      As mentioned earlier the night When Winter Solstice is the longest in the northern hemisphere and is the longest day in the southern half of them. But does this mean that the sun is the most backward in the northern hemisphere and the sunset is the most backward in the southern half of them?

      Many wonders and believed that it was true, but the truth is it is not. To understand it is necessary to know that the most backward sunset no relation to the time in which the sunrise or sunset happens. It's about "real time meridian" (true solar noon) The time when the sun is at its maximum height at her cut of the sky during the day. In early December, advanced real-time disappearing ten minutes from time at the winter solstice (December 21), and this difference makes the day when the sunset and sunrise most virgins in both hemispheres is not on the day of Winter Solstice.

     History accurately to determine the day when the most advanced sunset depends on the geographic latitude. Geographical zones following the north of the equator, this day be at the beginning of December, the areas in the far north of the globe (Canada and Alaska). So this day in mid-December, and close to the Arctic Circle, this day be identical to the day Winter Solstice. Incidentally, the most backward sunset does not occur in the summer solstice (in the northern hemisphere). But it happens in the beginning of January geographical areas following the north of the equator.