Planet EarthOrigin and evolution of land, atmosphere, water.Planet earth formed 4.5 billion years ago. About 4.6 bya, protoplanet Earth possibly formed by gravity as a random mixture of elements in a cold dust cloud. Meteorites and comets, high in ice and carbon, bombarded Earth most heavily between 4.5 to 4.4 bya and tapered off until 3.8 bya. Comets may have delivered several times as much water as exists in all of today’s oceans. |
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Visitors may touch this rock and mineral.
| Item on exhibit | |
| Hartzburgite | Found on the surface today, a type of high iron and magnesium rock that possibly existed during early crust formation. |
| Volcanoes
carried water Minerals, like muscovite, locked up oxygen and hydrogen. As Earth heated up and under certain conditions, chemical bonds broke and released water. Lava carried water to the surface. Under special conditions this muscovite could release water. |
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