Labels:text | font | screenshot | document OCR: THE MATERIAL of the Sun is in a gaseous state so that it has no definite boundary but fades into space. However, the Sun appears to have a relatively sharp edge because most of its light that reaches us comes from a layer only a few hundred kilometers thick that is called the photosphere and is regarded as being the surface of the Sun. Above it are the chromosphere and the corona, which together form the solar atmosphere. SOLAR WEATHER Superimposed on the steady shining of the Sun are short-lived disturbances that occur from time to time in the solar atmosphere and constitute a sort of solar weather. These range from relatively cool and dark areas called sunspots and relatively hot areas called plages, which may last for weeks or even months, to violent explosions called flares whose lives ...
