Time Zones of the World

The planet's population continues to explode: from 1 billion in 1820, to 2 billion in 1930, 3 billion in 1960, 4 billion in 1974, 5 billion in 1988, and 6 billion in 2000.  For the 21st century, the continued exponential growth in science and technology raises both hopes (e.g., advances in medicine) and fears (e.g., development of even more lethal weapons of war).

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).

1,018,057,389
(2005)