Summer Solstice
In 2009, summer begins June 21, 1:45 A.M. EDT (20:45
UT on June 20)
Solstice comes from the
Latin (sol, sun; sistit, stands). For several days before
and after each solstice, the sun appears to stand still in the
sky—that is, its noontime elevation does not seem to change.
Solstice, from the Latin for sun stands still,
in astronomy, either of the two points on the ecliptic that lie midway
between the equinoxes (separated from them by an
angular distance of 90°).
At the solstices the sun's apparent
position on the celestial sphere reaches its greatest distance above or
below the celestial equator, about 23 1/2° of
arc. At the time of summer solstice, around June 20 or 21, the sun is directly
overhead at noon at the Tropic of Cancer.
In the Northern Hemisphere the longest day and shortest night of the year
occur on this date, marking the beginning of summer. At winter solstice,
about December 22, the sun is overhead at noon at the Tropic of Capricorn; this marks the beginning
of winter in the Northern Hemisphere. For several days before and after each
solstice the sun appears to stand still in the sky, i.e., its noontime
elevation does not seem to change from day to day.
The
Columbia Encyclopedia, Fifth Edition Copyright © 1993, Columbia
University Press. Licensed from Inso Corporation. All rights reserved.
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