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Landfall-Learning > Geography

Geography - The Big Picture

For information about specific countries we are visiting, check out the various country links below.

The Blue Planet

Earth is the only planet whose English name does not derive from Greek/Roman mythology. The name derives from Old English and Germanic. There are hundreds of other names for our planet in other languages. Earth, of course, can be studied without the aid of spacecraft. Nevertheless it was not until the twentieth century that we had maps of the entire planet. Pictures of the planet taken from space are of considerable importance; for example, they are an enormous help in weather prediction and especially in tracking and predicting hurricanes. And they are extraordinarily beautiful.

Unlike the other planets planets in our solar system, Earth's crust is divided into several separate solid plates which float around independently on top of the hot mantle below. The theory that describes this is known as "plate tectonics". It is characterized by two major processes: spreading and subduction. Spreading occurs when two plates move away from each other and new crust is created by upwelling magma from below. Subduction occurs when two plates collide and the edge of one dives beneath the other and ends up being destroyed in the mantle. There is also transverse motion at some plate boundaries (e.g. the San Andreas Fault in California) and collisions between continental plates (e.g. India/Eurasia).

There are (at present) eight major plates:

  • North American Plate - North America, western North Atlantic and Greenland
  • South American Plate - South America and western South Atlantic
  • Antarctic Plate - Antarctica and the "Southern Ocean"
  • Eurasian Plate - eastern North Atlantic, Europe and Asia except for India
  • African Plate - Africa, eastern South Atlantic and western Indian Ocean
  • Indian-Australian Plate - India, Australia, New Zealand and most of Indian Ocean
  • Nazca Plate - eastern Pacific Ocean adjacent to South America
  • Pacific Plate - most of the Pacific Ocean (and the southern coast of California!)

There are also twenty or more small plates such as the Arabian, Cocos, and Philippine Plates. Earthquakes are much more common at the plate boundaries.

The Earth's surface is very young. In the relatively short (by astronomical standards) period of 500,000,000 years or so erosion and tectonic processes destroy and recreate most of the Earth's surface and thereby eliminate almost all traces of earlier geologic surface history (such as impact craters). Thus the very early history of the Earth has mostly been erased. The Earth is 4.5 to 4.6 billion years old, but the oldest known rocks are about 4 billion years old and rocks older than 3 billion years are rare. The oldest fossils of living organisms are less than 3.9 billion years old. There is no record of the critical period when life was first getting started.

71 Percent of the Earth's surface is covered with water. Earth is the only planet on which water can exist in liquid form on the surface. Liquid water is, of course, essential for life as we know it. The heat capacity of the oceans is also very important in keeping the Earth's temperature relatively stable. Liquid water is also responsible for most of the erosion and weathering of the Earth's continents, a process unique in the solar system today (though it may have occurred on Mars in the past).

The Countries

Coastal United States
Central America
South America
South Pacific Islands


Where's Landfall?

Test your knowledge of geography on our Where's Landfall pages. Here you'll find hints about various places we've visited or plan to visit. Using the hints and your map of the world, locate these hidden lands!