Southern Hemisphere

Earth's southern hemisphere highlighted in yellow (Antarctica not depicted).
Southern hemisphere from above the South Pole.

The Southern Hemisphere[1] is the half of a planet that is south of the equator—the word hemisphere (from the Greek word σφαιρα (sphere) +ημι(half)) literally means 'half ball'. It is also that half of the celestial sphere south of the celestial equator.

Earth's southern hemisphere contains all or parts of four continents (Antarctica, Australia, most parts of South America and southern half of Africa), four oceans (South Atlantic, Indian, South Pacific, and Southern) and most of Oceania. Several islands off the Asian continental mainland are also in the Southern Hemisphere. Due to the tilt of Earth's rotation relative to the Sun and the ecliptic plane, summer is December 21 to March 21 and winter is June 21 to September 22. September 22 is the vernal equinox and March 21 is the autumnal equinox.

Contents

Geography

Climates in the southern hemisphere overall tend to be slightly milder than those in the northern hemisphere except in the Antarctic which is colder than the Arctic. This is because the southern hemisphere has significantly more ocean and less land. Water heats up and cools down more slowly than land. The southern hemisphere is also significantly less polluted than the northern hemisphere because of lower overall population densities (a total of 10 to 12% of the human population), lower levels of industrialisation, and smaller land masses. (Air currents run mostly west–east so pollution does not easily spread north or south.) In the southern hemisphere the sun passes from east to west through the north, although north of the Tropic of Capricorn the mean sun can be directly overhead or due south at midday. The sun rotating through the north causes an apparent right-left trajectory through the sky unlike the left-right motion of the sun when seen from the northern hemisphere as it passes through the southern sky. Sun-cast shadows turn anticlockwise through the day and sundials have the hours increasing in the anticlockwise direction. Hurricanes and tropical storms spin clockwise in the southern hemisphere (as opposed to anticlockwise in the Northern Hemisphere) due to the Coriolis effect.

The southern temperate zone, a subsection of the southern hemisphere, is nearly all oceanic. The only countries that lie entirely within this zone are Uruguay, Lesotho, Swaziland and New Zealand. Countries lying partly in the zone are Chile (most of), Argentina (most of), Paraguay, Brazil, Namibia, Botswana, South Africa (most of), Mozambique, Madagascar and Australia (most of).

The South Pole is oriented towards the galactic centre and this, combined with clearer skies, makes for excellent viewing of the night sky from the southern hemisphere with brighter and more numerous stars.

Forests in the southern hemisphere have special features which set them aside from the northern hemisphere. Both Chile and New Zealand share, for example, unique beech species or Nothofagus. The eucalyptus is native to Australia but has now gone on to be planted in southern Africa and Latin America for pulp production and, increasingly, biofuel uses.

List of continents and countries

Continents

A famous photo of Earth from Apollo 17 (Blue Marble) originally had the south pole at the top; however, it was turned upside-down to fit the traditional perspective.

African countries

Entirely
Mostly
Partly

Asian countries

Entirely
Mostly
Partly

Oceania countries

Entirely
Mostly

America

Entirely
Mostly
Partly

Other territories

Aurora australis appearing in the night sky of Swifts Creek, 100 km north of Lakes Entrance, Victoria, Australia
Aurora australis appearing from Stewart Island/Rakiura at the southern point of the South Island of New Zealand.

See also

References

  1. ↑ Merriam Webster's Online Dictionary (based on Collegiate vol., 11th ed.) 2006. Springfield, MA: Merriam-Webster, Inc.
Hemispheres of the Earth
Northern hemisphere • Southern hemisphere • Eastern hemisphere • Western hemisphere • Land hemisphere • Water hemisphere