Illustrated Encyclopedia of the Earth
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The first major era of the Phanerozoic is called the Paleozoic, and the Cambrian is the first period of the Paleozoic era. “The Cambrian Explosion of Life” was the rapid appearance of almost all forms of life. Paleontologists and geologists have studied fossils of archaea, bacteria, algae, fungi, plants, and animals that lived during the Cambrian period. The Cambrian was followed by the Ordovician, Silurian, Devonian, Carboniferous, and Permian periods. Tectonic activity such as subduction and faulting has shaped the crust into a variety of landscapes. Earth’s highest point is Mount Everest, Nepal, which soars 8,850 kilometers (29,035 feet) in the Himalaya Mountains in Asia. Mount Everest continues to grow every year, as subduction drives the Indo-Australian tectonic plate below the Eurasian tectonic plate. Subduction also creates Earth’s deepest point, the Mariana Trench, about 11 kilometers (6.9 miles) below the surface of the Pacific Ocean. The heavy Pacific plate is being subducted beneath the small Mariana plate. Eventually, Earth began to cool and its materials began to separate. Lighter materials floated upward and formed a thin crust. Heavier materials sank toward Earth’s center. Eventually, three main layers formed: the core, the mantle, and the crust.
Earth has one natural satellite, the moon. Earth is the only planet in the solar system to have one moon. Venus and Mercury do not have any moons, for example, while Jupiter and Saturn each have more than a dozen.Records the default button state of the corresponding category & the status of CCPA. It works only in coordination with the primary cookie. Paleontologists, geologists, and other scientists divide Earth’s history into time periods. The largest time period is the supereon, and only applies to one unit of time, the Precambrian. Eons, eras, and periods are smaller units of geologic time. Earth is an oblate spheroid. This means it is spherical in shape, but not perfectly round. It has a slightly greater radius at the Equator, the imaginary line running horizontally around the middle of the planet. In addition to bulging in the middle, Earth’s poles are slightly flattened. The geoid describes the model shape of Earth, and is used to calculate precise surface locations.
Jupiter, Saturn, Uranus, and Neptune all have atmospheres made mostly of hydrogen and helium. These planets are called gas giants, because they are mostly made of gas and do not have a solid outer crust. Earth is the planet we live on, one of eight planets in our solar system and the only known place in the universe to support life.Coupled with numerous genealogical tables and a unique Chronology of the First Age, it will provide an indispensable aid to every reader’s discovery of Tolkien’s world.
John Garth has written excellently on Tolkien’s formative wartime experiences in Tolkien and the Great War. [ The Worlds of J.R.R. Tolkien] now brings near-nerdish knowledge to bear on other parts of Tolkien’s thought-universe, investigating other influences that molded Middle-earth…[An] erudite and exhaustive exploration of Tolkien’s compelling creation. –Derek Turner, Chronicles" The Complete Guide to Middle-earth has been compiled to enhance the reader’s enjoyment of Tolkien’s books by bringing together in an A-Z sequence all the key facts and information about names, places, languages and events from The Hobbit, The Lord of the Rings and The Silmarillion.Garth identifies the locales that served as the basis for Hobbiton, the elven valley of Rivendell, the Glittering Caves of Helm’s Deep, and many other settings in Middle-earth, from mountains and forests to rivers, lakes, and shorelands. He reveals the rich interplay between Tolkien’s personal travels, his wide reading, and his deep scholarship as an Oxford don. Garth draws on his profound knowledge of Tolkien’s life and work to shed light on the extraordinary processes of invention behind Tolkien’s works of fantasy. He also debunks popular misconceptions about the inspirations for Middle-earth and puts forward strong new claims of his own. The atmosphere has a layered structure. From the ground toward the sky, the layers are the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Up to 75 percent of the total mass of the atmosphere is in the troposphere, where most weather occurs. The boundaries between the layers are not clearly defined, and change depending on latitude and season.