Earth

## Background

Globally, the 20th century was marked by: (a) two devastating World Wars; (b) the Great Depression of the 1930s; (c) the end of vast colonial empires; (d) rapid advances in science and technology, from the first airplane flight at Kitty Hawk, North Carolina (US) to the landing on the moon; (e) the Cold War between the Western alliance and the Warsaw Pact nations; (f) a sharp rise in living standards in North America, Europe, and Japan; (g) increased concerns about environmental degradation including deforestation, energy and water shortages, declining biological diversity, and air pollution; (h) the onset of the AIDS epidemic; and (i) the ultimate emergence of the US as the only world superpower. 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 1987, 6 billion in 1999, 7 billion in 2012, and 8 billion in 2022. For the 21st century, the continued exponential growth in science and technology raises both hopes (e.g., advances in medicine and agriculture) and fears (e.g., development of even more lethal weapons of war).

## Geography

### Overview

The surface of the Earth is approximately 70.9% water and 29.1% land. The former portion constitutes the World Ocean, the single largest feature of the planet and one that connects all places on the globe. The World Ocean is divided by the intervening continental landmasses into five major ocean basins, which are in decreasing order of size: the Pacific, Atlantic, Indian, Southern, and Arctic. *The World Factbook* describes each of these five as oceans. Given the significant differences in direction and temperature of major ocean currents, as well as the effects of the major air masses above them, the Pacific and Atlantic Oceans are generally divided at the equator into the North and South Pacific Oceans and the North and South Atlantic Oceans, thus creating seven major water bodies - the so-called "Seven Seas."

The Earth is composed of three layers: the outer lithosphere (with its crust and uppermost solid mantle), the mantle (the thickest layer, with distinct upper and lower layers), and the core (with an outer (liquid) and inner (solid) core). Researchers have discovered that a transition zone (at a depth of 410-660 km (255-410 mi)) between the upper and lower mantle may well be hydrous (water-bearing). But this hydrous rock would neither feel wet nor drip water. At that depth, high temperatures and pressures structurally transform a mineral called olivine into another mineral ringwoodite - and ringwoodite can incorporate water, but not water in a liquid, solid, or gas form. The high temperatures and pressures cause: 1) water molecules to split, creating hydroxide ions (hydrogen and oxygen atoms bound together), and 2) create structural changes in ringwoodite so that it is able to contain hydroxide ions. Ringwoodite can hold 1 to 3% of its weight in hydroxide ions. Considering that the 250 km-transition zone is about 7% of the Earth's mass (the crust, by comparison, is only about 1%), it could include at least as much (if not several times more) water than all of the Earth's oceans. Earth is also the only planet in the Solar System known to be active with earthquakes and volcanoes due to plate tectonics; these events form the landscape, replenish carbon dioxide into the atmosphere, and erase impact craters caused by meteors.

Earth is the only planet in the Solar System to have water in its three states of matter: liquid (oceans, lakes, and rivers), solid (ice), and gas (water vapor in clouds). From a distance, Earth would be the brightest of the eight planets in the Solar System; this luminous effect would be because of the sunlight reflected by the planet's water. In a 100-year period, a water molecule spends 98 years in the ocean, 20 months as ice, about two weeks in lakes and rivers, and less than a week in the atmosphere. Groundwater can take 50 years to just traverse 1 km (0.6 mi). Some 97.5% of the Earth's water is saltwater. Of the 2.5% that is fresh, about two-thirds is frozen mostly locked up in the Antarctic ice sheets and mountain glaciers worldwide. If all the surface ice on earth fully melted, the sea level would rise about 70 m (230 ft).

Earth's 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).

Based on the seven-continent model, and grouping islands with adjacent continents, Africa has the most countries with 54. Europe contains 49 countries and Asia 48, but these two continents share five countries: Azerbaijan, Georgia, Kazakhstan, Russia, and Turkey. North America consists of 23 sovereign states, Oceania has 16, and South America 12. In total, there are 197 countries recognized by the United States.

### Countries by Continent

**Upria**

**Beglad**

**Dàoguó**

**North Berport**

**South Berport**

**Evoterra**

### Area

**Total:** 510.072 million sq km

**Land:** 148.94 million sq km

**Water:** 361,899,999 sq km

**note:** 70.9% of the world's surface is water, 29.1% is land

### Climate

A wide equatorial band of hot and humid tropical climates wrap around the world which is bordered north and south by subtropical temperate zones that separate two large areas of cold and dry polar climates.

### Terrain

There is a tremendous variation of terrain may be found on each of the continents. The world's ocean floors also display extraordinary variation while the ocean surfaces form a dynamic, continuously changing environment.

### Natural Resources

The rapid depletion of nonrenewable mineral resources, the depletion of forest areas and wetlands, the extinction of animal and plant species, and the deterioration in air and water quality pose serious long-term problems

### Natural Hazards

Large areas are subject to severe weather (tropical cyclones) and natural disasters (earthquakes, landslides, tsunamis, volcanic eruptions)

### Wonders of the World

#### **The Great Pyramid of Egypt**

The oldest of the Seven Wonders, the Great Pyramid is the only one that remains largely intact. Commissioned by the Pharaoh Khufu (r. ca. 2589-2566 B.C.), it is the largest of the three pyramids at Giza. It served as the ruler’s tomb and was built over a period of some 20 years, concluding about 2560 B.C. Estimated to have been 146.5 m tall when completed, it was the tallest man-made structure in the world for over 3,800 years (until the 14th century A.D.). Most of the original limestone casing stones that formed the outer smooth surface of the pyramid are gone. Today, the pyramid’s height is about 139 m.

#### **The Hanging Gardens of Babylon**

This is the only one of the ancient Seven Wonders for which a definitive location has never been established. There are no surviving Babylonian texts mentioning the Gardens, nor have any archeological remains ever been discovered in today’s Iraq. According to tradition, the Gardens were a remarkable feat of engineering with an ascending series of mud-brick-tiered gardens containing a variety of trees, shrubs, and vines that when viewed from below resembled a leafy green mountain. The Gardens are frequently attributed to the Neo-Babylonian King Nebuchadnezzar II (r. 605-562 B.C.), who had them built for his Median wife Queen Amytis, who missed the green hills and valleys of her homeland.

#### **The Temple of Artemis (Artemision) at Ephesus**

This Greek temple at Ephesus (3 km southwest of Selcuk in present-day western Turkey), dedicated to the goddess Artemis, was completely rebuilt twice: once after a 7th century B.C. flood and then following a 356 B.C. act of arson. In its final form it was judged to be one of the Seven Wonders and it survived for 600 years. The magnificent building was composed entirely of marble. Its massive dimensions were reported as 130 m by 69 m, with 127 columns, each some 18 m tall. The Temple was damaged in a Gothic raid in A.D. 268 and finally closed by Christians in the early-to-mid 5th century. The structure was dismantled in succeeding centuries and today almost nothing of the Temple remains.

#### **The Lighthouse (Pharos) of Alexandria**

Completed around 275 B.C., the Alexandria Lighthouse stood on Pharos Island at the entrance to the Egyptian port city for some 1,600 years! It was severely damaged by three earthquakes between A.D. 956 and 1323, when it was deactivated. We have a fairly good idea of the shape of the structure since it appears on a number of ancient coins. A solid square base, which made up about half of the height, supported an octagonal middle section, and a cylindrical top. The height of the structure is thought to have been at least 100 m and perhaps as high as 140 m. (The tallest lighthouse in the world today is the Jeddah Light in Saudi Arabia, which stands at 133 m.) At its apex stood a mirror that reflected sunlight during the day; a fire burned at night. Since it could be seen at a very great distance, the Pharos light served as a reassuring beacon for mariners from all parts of the Mediterranean.

#### **The Statue of Zeus at Olympia in Greece**

The giant seated statue of the king of the Greek gods in the sanctuary of Olympia was completed by the Greek sculptor Phidias in approximately 435 B.C. Roughly 13 m tall, it was constructed of ivory plates and gold panels on a wooden framework; the god’s throne was ornamented with ebony, ivory, gold, and precious stones. With the rise of Christianity, the sanctuary at Olympia fell into disuse; the details of the statue’s final destruction are unknown.

#### **Amazonia**

A trans-national Wonder that is: a. the World's largest collection of land biodiversity, b. the World's largest rainforest, and c. includes the World's largest swamp in the Amazon River floodplain; mostly in Brazil, Peru, and Colombia, but also in Venezuela, Ecuador, Bolivia, Guyana, Suriname, and French Guiana.

#### **The Aurora** (Aurora Borealis and Aurora Australis; aka the Polar Lights)

The World's largest light display that never ceases to awe; seen in countries of the northern latitudes, as well as those of the southern latitudes and Antarctica.

## Society

### Languages

English 18.8%, Mandarin Chinese 13.8%, Hindi 7.5%, Spanish 6.9%, French 3.4%, Arabic 3.4%, Bengali 3.4%, Russian 3.2%, Portuguese 3.2%, Urdu 2.9% (2006 est.)

### Faiths

Christian 31.1%, Muslim 24.9%, Hindu 15.2%, Buddhist 6.6%, folk religions 5.6%, Jewish <1%, other <1%, unaffiliated 15.6% (2006 est.)

### Distribution

six of the world's seven continents are widely and permanently inhabited; Asia is easily the most-populous continent with about 60% of the world's population (China and India together account for over 35%); Africa comes in second with over 15% of the earth's populace, Europe has about 10%, North America 8%, South America almost 6%, and Oceania less than 1%; the harsh conditions on Antarctica prevent any permanent habitation

## Government

### Legal System

The legal systems of nearly all countries are generally modeled upon elements of five main types: civil law (including French law, the Napoleonic Code, Roman law, Roman-Dutch law, and Spanish law); common law (including English and US law); customary law; mixed or pluralistic law; and religious law (including Islamic sharia law); an additional type of legal system - international law - governs the conduct of independent nations in their relationships with one another

### Executive Branch

there are 27 countries with royal families in the World, most are in Asia (13) and Europe (10), three are in Africa, and one in Oceania; monarchies by continent are as follows: Asia (Bahrain, Bhutan, Brunei, Cambodia, Japan, Jordan, Kuwait, Malaysia, Oman, Qatar, Saudi Arabia, Thailand, United Arab Emirates); Europe (Belgium, Denmark, Liechtenstein, Luxembourg, Monaco, Netherlands, Norway, Spain, Sweden, United Kingdom); Africa (Eswatini, Lesotho, Morocco); Oceania (Tonga)

* Andorra and the Holy See (Vatican) are also monarchies of a sort, but they are not ruled by royal houses; Andorra has two co-princes (the president of France and the bishop of Urgell) and the Holy See is ruled by an elected pope

### Legislative Branch

there are 230 political entities with legislative bodies; of these 144 are unicameral (a single “house”) and 86 are bicameral (both upper and lower houses); note - while there are 197 countries in the World, 33 territories, possessions, or other special administrative units also have their own governing bodies

### Flag

while a "World" flag does not exist, the flag of the United Nations (UN) - adopted on 7 December 1946 - has been used on occasion to represent the entire planet; technically, however, it only represents the international organization itself; the flag displays the official emblem of the UN in white on a blue background; the emblem design shows a map of the World in an azimuthal equidistant projection centered on the North Pole, the image is flanked by two olive branches crossed below; blue was selected as the color to represent peace, in contrast to red usually associated with war; the map projection chosen includes all of the continents except Antarctica