Summer Solstice (June 21, 2011)

Summer Solstice (June 21, 2011)

Summer Solstice from the space. This NASA image is acquierd on June 21, 2011.

A solstice is an event occurring when the Sun appears to reach its most northerly or southerly excursion relative to the celestial equator on the celestial sphere. Two solstices occur annually, on about June 21 (summer solstice) and December 21 (winter solstice). The word solstice is derived from the Latin sol (“sun”) and sistere (“to stand still”), because at the solstices, the Sun’s declination “stands still”; that is, the seasonal movement of the Sun’s daily path (as seen from Earth) stops at a northern or southern limit before reversing direction.
On the “summer solstice” day (it actually occurs at the beginning of the winter in the southern hemisphere, so “June solstice is a more accurate term”) the Sun appears to reach its highest point in the sky at the northern hemisphere, at latitudes outside the tropics. Also the longest day time and shortest night time of the year occur. Within the tropics, the Sun appears directly overhead at solar noon days to 3 months before and after the summer solstice.

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