Idk Lol Essay

421 WordsAug 29, 20142 Pages
xxiv Prequel where they formed the Earth’s core. The metallic core generates the magnetic field that protects us from some of the more destructive forms of solar radiation. Lighter materials formed a squashy, semi-molten middle layer known as the “mantle.” Even lighter materials stayed at the surface. These cooled more rapidly to form the eggshell-thin layer that we call the “crust.” The crust is just a few miles deep. The lightest materials of all were the gases. These bubbled up through the Earth’s volcanic surface to form the first atmosphere. The first 500 million years of the Earth’s history are known as the “Hadean” or “hellish” era. The Earth was hot, it was bombarded with asteroids, and its atmosphere contained no free oxygen. No living things could have survived. But slowly the Earth cooled. Eventually water vapor, circulating the Earth in vast clouds, began to rain down onto the surface to form the first oceans. It was almost certainly in these early oceans that a new form of complexity began to appear: life. Water, in liquid form, provides a wonderful environment for chemical reactions. In air, atoms move past each other too fast to pair up. In solids, they barely move at all. Water is just right: Chemicals move around but not too fast, so if they are compatible, they can pair up to start forming more complicated chemicals. Somewhere, probably deep in the early seas, where there was energy from deep-sea volcanoes and an abundance of chemicals, more and more complex chemicals began to form. By 3.5 billion years ago, within just a billion years of the Earth’s creation, some of these chemicals formed the first living organisms. Biologists call these tiny, simple, one-celled organisms “prokaryotes,” and prokaryotes remain the most common organisms on Earth even today. Like all prokaryotes, the first living organisms would have been too small to see. But they

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