The estimated total surface area of the Earth is 510,100,448 square kilometre, of which the sea or hydrosphere covers five-sevenths, or more accurately, 70.78 per cent (361,059,226 square kilometre) and the land or lithosphere two-sevenths or 29.22 per cent (149,041,182 square kilometre). The Earth has a mass of about 5.882 X 1021 tons) (estimated) and has a density 5.515 times that of water or 5.517 kg/litre). The equatorial circumference of the earth is 40,075.03 kilometre with a polar or meridional circumference of 40,007.89 kilometre indicating that the earth is not a true sphere but an ellipsoid, flattened at the poles. The earth also has a slight ellipticity at the equator.
Population: According to the United Nations statistics, the world's population estimated at 5.666 billion in 1994, could soar to 6.28 billion by 2000 and to 8.5 billion by 2025. At the beginning of the century, the world population was 1.663 billion and 5.575 billion in mid-1993.
The average daily increase in the world's population has been estimated at about 256,000 or an average of approximately 178 per minute.
The all-time peak annual increase of 2.06 per cent in the period 1965-70 declined to 1.74 per cent by 1985-90. By 2025 this should decline to 0.99 per cent. In spite of the reduced percentage increase, word population is currently growing by more than 93 million every year. Projections issued by the United Nations have estimated that the population would stabilise at around 11.6 billion in around 2150.
The crude birth rate-the number of births per 1,000 population-for the whole world was estimated to be 27.0 per 1,000 in 1985-90. The highest rate estimated by the United Nations for 1985-90 was 55.6 per 1,000 for Malawi. Excluding the Vatican City, where the rate is negligible, the lowest recorded rate was 9.5 per 1,000 for San Marino for the same period.
The crude death rate-the number of deaths per 1,000 population of all ages-for the whole world was an estimated 9.7 per 1,000 in 1985-90. East Timor had a rate of 45.0 per 1,000 from 1975-80, although this had subsided to 21.5 in 1985-90. The highest estimated rate in the same period was 23.4 for Sierra Leone. The lowest estimated rate for 1985-90 was 3.5 deaths for 1,000 for Bahrain.
The rate of natural increase for the whole world was estimated to be 17.3 (27.0 births less 9.7 deaths) per 1,000 in 1985-90 compared with a peak 20.6 per 1,000 in 1965-70. The highest of the latest available recorded rates was 37.4 (43.0 less 5.6) for Oman in 1985-90. The lowest rate of natural increase in any major independent country in recent times was in the Hungary, which actually experienced a population decline in 1985-90 with a figure of -1.7 per 1,000 (11.9 births and 13.6 deaths).
There are estimated to be 1,014 males in the world for every 1,000 females. The country with the largest recorded shortage of women is the United Arab Emirates, which has an estimated 484 to every 1,000 males. The country with the largest recorded shortage of males is Ukraine, with an estimated 1,154 females to every 1,000 males.
Most populous country: The largest population of any country is that of China, which has massive share of the world's population-about 25 per centt. The rate of natural increase in the People's Republic of China is now estimated to be 37,000 a day or 13.6 million per year In early 1995, the population of China was estimated to be 1.2 billion
Least populous country: The independent state with the smallest population is the Vatican City or the Holy See, with 1,800 inhabitants in 1993.
Most densely populated: The most densely populated territory in the world is the Portuguese province of Macau on the southern coast of China. It has an estimated population of 378,000 (mid-1993 estimate) in an area of 18 square kilometres giving a density of 21,000 per square kilometre.
Number of countries: The world comprises of 191 sovereign countries and 65 non-sovereign or other territories (dependencies of sovereign states, territories claimed in Antarctica and disputed territories), making a total of 256 as in April 1994.
Largest country: The country with the greatest area is Russia, with a total area of 17,075,400 sq km, or 11.5 per cent of the world's total land area. It is 70 times larger than U.K., but with a population in 1993 of 148 million has only 2 55 times more people than the U.K.
Smallest country: The smallest independent country in the world is the State of the Vatican City or Holy See, which was made an enclave within the city of Rome, Italy on February 11, 1929. The enclave has an area of 0.44 sq km.
Smallest republic : The world's smallest republic is Nauru, less than one degree south of the equator in the Western Pacific, which became independent on January 31, 1968 It has an area of 2,129 hectares and a population of 10,000 (latest estimate 1993).
Smallest colony: The smallest colony in the world is Gibraltar (since 1969, the city of Gibraltar), with an area of 5.8 square kilometres. Pitcairn Island, the only inhabited (55 people in late-1993) island of a group of four (total area 4 square kilometres) has an area of 388 hectares (960 acres).
Most populous city: The most populous urban agglomeration in the world is the Tokyo, which was listed in the United Nations Prospects of World Urbanisation 1992 as having a population of 25,000,000. By 2000 this is expected to increase to 28,000,000.
Largest city: The world's largest city, in area, is Mount Isa, Queensland, Australia which has an administered area of 41,225 square kilometres.
Highest capital: The highest capital in the world, before the domination of Tibet by China, was Lhasa, at an elevation of 3,684 metres above sea level. La Paz, the administrative and de facto capital of Bolivia, stands at an altitude of 3,631 metres above sea level.
Highest town: Wenchuan, the new town founded in 1955 on the Chinghai-Tibet road, located north of the Tangle range in China at 5,100 metres above sea level, is the highest town in the world.
Least populous town: China, the world's most populous country, has what may be the world's least populous town. Yumen, in the remote Himalayan region of Tibet, has only three residents, an elderly father and his two daughters. The town has a township Government, an administrative head, an official seal and an emblem. The father, Sangqu, 72, has retired as the town head and has been succeeded by his older daughter Zhuoga. The remote town lies 550 km southeast of the capital, Lhasa. Dozens of Families once lived in Yumen, but slowly they all moved away. By 1989, only Sangqu's family was left.