The
Tropic of Capricorn is a
parallel that circles around
the Earth at a latitude of about 23°22'S. What makes
this latitude
special is that is the southernmost point on
the globe where the Sun can stand directly overhead; this
happens at the
summer solstice, which is in December at the
Southern Hemisphere. Hence, it marks the south boundary of
the
tropics.
On a globe, this tropic cuts through the north of Chile
and Argentine, the Atlantic Ocean, goes through the north
of South Africa, goes through Madagascar, the Indian
Ocean, trough Australia, and the Pacific Ocean, and passes
over the Pacific Ocean to arrive again in Chile If you
were to make this tour, you'd mainly encounter water and
desert
Like the Tropic of Cancer, the Tropic of Capricorn moves
over the surface of the earth due to precession and
nutation. Simply put, the tilt of the axis of the Earth
varies in time, at time scales varying between days and
41,000 years. Hence, the Tropic of Capricorn moves as well.
The current trend is an average movement of 15 meters to the
north per year.
The name of the tropic comes from the constellation of
Capricorn. When the tropic was named, the summer solstice
at the southern hemisphere occured when the Sun was in the
constellation of Capricorn. Nowadays, the Sun is in the
constellation of Sagittarius at this solstice.
See also: Tropic of Cancer.
Sources:
- http://en.wikipedia.org/wiki/Tropic_of_Cancer
- http://en.wikipedia.org/wiki/Tropic_of_Capricorn
- http://www.crystalinks.com/precession.html
- http://www.starlink.rl.ac.uk/star/docs/sun67.htx/node206.html
- http://www.pietro.org/Astro_Util_StaticDemo/MethodsNutationVisualized.htm