The Southern Hemisphere is part of a rotating astronomical body that lies south of its equator. The word hemisphere (from the Greek word σφαιρα (sphere) +ημι (half)) literally means 'half ball' or "half sphere". It is also that half of the celestial sphere south of the celestial equator.
On Earth the Southern Hemisphere contains all or parts of four continents (Antarctica, Australia, about 9/10 of South America and the southern third of Africa), four oceans (Indian, South Atlantic, Southern, and South Pacific) 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 from December to March and winter is from June to September. September 22 or 23 is the vernal equinox and March 20 or 21 is the autumnal equinox.
Overall may tend to be slightly milder than those in the Northern Hemisphere at similar latitudes except in the Antarctic which is colder than the Arctic. This is because the Southern Hemisphere has significantly more ocean and much 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 throughout the day and sundials have the hours increasing in the anticlockwise direction. During solar eclipses viewed from a point to the south of the Tropic of Capricorn the Moon moves from left to right on the disc of the Sun (see, for example, photos with timings of the Solar eclipse of November 13, 2012), while viewed from a point to the north of the Tropic of Cancer (i.e., in the Northern Hemisphere) the Moon moves from right to left during a solar eclipses.
The southern temperate zone, a subsection of the Southern Hemisphere, is nearly all oceanic. This zone includes all of Uruguay, Lesotho, Swaziland, and New Zealand; most of Chile, Argentina, South Africa, and Australia; and parts of Paraguay, Brazil, Namibia, Botswana, Mozambique, and Madagascar.
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 and microcontinents
- Africa (approximately one third, from south of Libreville in Gabon in the west to south of Somalia in the east)
- Asia (the very southern island portion including East Timor, the most of Indonesia and a few islets of the Maldives)
- Australia (the entire mainland is in the Southern Hemisphere)
- South America (mostly, south of the Amazon River mouth in the east and Quito in the west)
- Zealandia (New Caledonia, the New Zealand landmass and associated islands are wholly within the Southern Hemisphere)
Countries and territories