The surface of the earth is
approximately 70.9% water and 29.1% land. The former portion is divided into
large water bodies termed oceans. The World Factbook recognizes and describes
five oceans, which are in decreasing order of size: the Pacific Ocean, Atlantic
Ocean, Indian Ocean, Southern Ocean, and Arctic Ocean.
The land portion is
generally divided into several, large, discrete landmasses termed continents.
Depending on the convention used, the number of continents can vary from five
to seven. The most common classification recognizes seven, which are (from
largest to smallest): Asia, Africa, North America, South America, Antarctica,
Europe, and Australia. Asia and Europe are sometimes lumped together into a Eurasian
continent resulting in six continents. Alternatively, North and South America
are sometimes grouped as simply the Americas, resulting in a continent total of
six (or five, if the Eurasia designation is used).
North America is commonly
understood to include the island of Greenland, the isles of the Caribbean, and
to extend south all the way to the Isthmus of Panama. The easternmost extent of
Europe is generally defined as being the Ural Mountains and the Ural River; on
the southeast the Caspian Sea; and on the south the Caucasus Mountains, the
Black Sea, and the Mediterranean. Portions of Azerbaijan, Georgia, Kazakhstan,
Russia, and Turkey fall within both Europe and Asia, but in every instance the
larger section is in Asia. These countries are considered part of both
continents. Armenia and Cyprus, which lie completely in Western Asia, are
geopolitically European countries.
Asia usually incorporates
all the islands of the Philippines, Malaysia, and Indonesia. The islands of the
Pacific are often lumped with Australia into a "land mass" termed
Oceania or Australasia. Africa's northeast extremity is frequently delimited at
the Isthmus of Suez, but for geopolitical purposes, the Egyptian Sinai
Peninsula is often included as part of Africa.
Although the above
groupings are the most common, different continental dispositions are
recognized or taught in certain parts of the world, with some arrangements more
heavily based on cultural spheres rather than physical geographic
considerations.
Area:
total: 510.072 million sq km
land: 148.94 million sq km
water: 361.132 million sq km
