Earth

**Earth** is the only planet in the universe known to harbor life, as well as the only planet to have bodies of liquid water present on the surface. Orbiting a main sequence star in a quiet arm of the Milky Way Galaxy, its rich geological and geographical history has been only rarely disturbed by the impact of asteroids and meteorites. Humans have explored virtually the entire planet, naming and cataloguing all points of interest, no matter how unimportant to the explorer or the organization. This exploration was followed in time by scientific surveying, as well as international conventions on the minutiae of geographic exploration and surveying. With the advent of modern technology such as computers and satellites, the Earth is coming into an ever-clearer view.

Earth is composed of 2 main biological and geographical parts: dry land and water. The part of the Earth covered in water is termed, for the most part, the oceans, though there exist many bodies of water too small to be an ocean or are entirely disconnected from an ocean. The ocean consists of very low-lying, typically flat or hilly terrain occasionally punctuated by islands, seamounts, and volcanoes. The oceans also have deep trenches where tectonic plates collide, forcing one under the other; the deepest trench, Marianas Trench, is deeper than Mount Everest is tall. Mauna Kea, the world's tallest mountain as measured from base, is far taller than Mount Everest as well; since nearly 16,000 ft of the mountain is submerged, Mauna Kea rises only 14,000 ft into the air, placing it a mere 15th in the world. The Atlantic Ocean has the world's longest and most rugged chain of mountains, termed the Mid-Atlantic Ridge; this ridge is produced by a spreading rift and runs from far north of Iceland to the remote waters of Bouvet Island.

The dry part of Earth, not covered in any water, is divided into four main bodies of land; America, Afro-Eurasia, Australasia, and Antarctica. Afro-Eurasia is by far the largest, both in terms of human population and in land area, and has a wide array of geographic features, from high plateaus in Tibet and the dozens of navigable waterways in Europe to the vast steppes of Central Asia and the unforgiving Sahara Desert of Africa. America is divided into North and South, with a narrow isthmus connecting the two; the American Cordillera is the world's longest continuous mountain chain, extending from western Alaska down the west coast of America all the way to Tierra del Fuego, joining the Scotia Arc, which joins to the Antarctic Cordillera as well. Australasia consists of the islands of Australia and New Zealand, as well as the tiny islands scattered throughout the Pacific Ocean; Australia is home to an enormous desert as well as landforms not found elsewhere on Earth, while New Zealand is a remote group of islands that are the remnants of a submerged "Zeelandia" continent. Antarctica is an ice-covered continent at the southern extremity of the Earth; it hosts unique, undisturbed geography and geology not found anywhere else but Greenland, and in far greater quantity.

With nearly 8 billion human inhabitants, the Earth has no shortage of brave explorers who traveled hundreds if not thousands of miles to lands that nobody knew existed before. Explorers have braved the treacherous Magellan Straits, traveled all around North America in search for the fabled Northwest Passage, and survived (sometimes didn't) landings on strange islands in the South Pacific Ocean, some of which were inhabited by cannibals. The great adventures these explorers embarked on spurred an eager and powerhungry Europe into action, exploring and colonizing most of the world, for better or worse. In their wake, millions of natives perished from disease or war, while colonizers harnessed the fertile lands that could often be found to grow cash crops in abundance. As cash crops crashed the world economy and the Industrial Revolution came underway, colonies and newly independent nations turned to machines to perform heavy labor, and later, almost any labor. Modern society has still not lost the thirst for discovery that the Age of Adventure was so renowned for, sending robotic missions to distant celestial objects in search for a neighbor to share the universe with. However, growing crises at home on Earth, spurred on by globalization, are threatening the very institutions of science and discovery and humanity itself, corrupting the world into disease, poverty, and war, draining money, energy, and resources at an ever-growing pace.