A solar storm is a term used for atmospheric effects felt on Earth from certain events that occur on the Sun. Solar storms occur when the Sun emits huge bursts of energy in the form of solar flares and coronal mass ejections (CMEs) . Solar flares are intense localized eruptions of electromagnetic radiation in the Suns atmosphere, while CMEs are huge bubbles of coronal plasma threaded with intense magnetic field lines that are ejected from the Sun over several hours. These phenomena send a stream of electrical charges and magnetic fields toward the Earth at a speed of about three million miles per hour. When a solar storm strikes the Earth, it often produces a dazzling “northern lights" display in parts of the atmosphere that can be seen in areas close to the Arctic Circle. Solar storms can also disrupt satellites and various forms of electronic communications. Solar radiation storms are another type of solar storm that occur when a large-scale magnetic eruption, often causing a CME and associated solar flare, accelerates charged particles in the solar atmosphere to very high speeds. These storms can cause geomagnetic storms that disrupt satellites and electrical power grids. Scientists who study solar storms have discovered that the frequency of solar flares appears to follow an 11-year solar cycle.