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The Sun is 1.4 million kilometers (4.643 light-seconds) wide, about 109 times wider than Earth, or four times the Lunar distance, and contains 99.86% of all Solar System mass. The Sun is a G-type main-sequence star that makes up about 99.86% of the mass of the Solar System. [26]
At local noon the winter Sun culminates at −3.44°, and the summer Sun at 43.44°. Said another way, during the winter the Sun does not rise above the horizon, it is the polar night. There will be still a strong twilight though. At local midnight the summer Sun culminates at 3.44°. Said another way, it does not set; it is the polar day.
Solar cycles are nearly periodic 11-year changes in the Sun's activity that are based on the number of sunspots present on the Sun's surface. The first solar cycle conventionally is said to have started in 1755. The source data are the revised International Sunspot Numbers (ISN v2.0), as available at SILSO. [1]
The shortest day is two weeks away, but the earliest sunsets are here. The earliest sunset (Dec. 4) and latest sunrise (Jan. 11) are 38 days apart.
Also, unlike most other solar measurements, sunrise occurs when the Sun's upper limb, rather than its center, appears to cross the horizon. The apparent radius of the Sun at the horizon is 16 arcminutes. [1] These two angles combine to define sunrise to occur when the Sun's center is 50 arcminutes below the horizon, or 90.83° from the zenith. [1]
After two solar cycles, the Sun's magnetic field returns to its original state, completing what is known as a Hale cycle. This cycle has been observed for centuries by changes in the Sun's appearance and by terrestrial phenomena such as aurora but was not clearly identified until 1843.
In exchange, the sun will start setting around 7:34 p.m., giving you an extra hour of daylight. But why do the clocks change twice a year? What is daylight saving time anyway?
The Islamic calendar is a purely lunar calendar and has a year, whose start drifts through the seasons and so is not a solar calendar. The Maya Tzolkin calendar, which follows a 260-day cycle, has no year, therefore it is not a solar calendar.