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Overlying the core is the radiation zone where the high-energy photons produced in the fusion reactions collide with electrons and ions to be re-radiated in the form of light and heat. Beyond the radiation zone is a convection zone in which currents of gas flow upwards to release energy at the surface before flowing downwards to be reheated. These circulating currents create the Sun's mottled appearance, or granulation. The surface layers, or photosphere, from which the light we see comes, are some hundreds of kilometres thick. In these layers, manifestations of solar activity occur, such as sunspots and flares. High-speed atomic particles released in flares stream through space, affecting the Earth and its environment. They cause radio interference, geomagnetic storms, and aurorae. The layer over the photosphere is the chromosphere, visible as a glowing pinkish ring during a total solar eclipse. Spicules and prominences erupt through the chromosphere. The thinnest, outermost layers, forming the solar corona, merge into the interplanetary medium.
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