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Musical Tone Music Narrator: Solar flares may seem like far-away events, but they can
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damage satellites and even ground-based technologies and power grids. Every 11 years, as the sun
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reaches it's maximum activity they become bigger and more common, and that increases
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the chances that one will significantly affect Earth. So what are these solar eruptions?
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A solar flare is basically an explosion on the surface of the sun ranging from minutes
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to hours in length. Large flares can release enough energy to power the entire United States
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for a million years. Flares happen when the powerful magnetic fields in and around the
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sun reconnect. They're usually associated with active regions, often seen as sun spots,
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where the magnetic fields are strongest. Flares are classified according to their strength.
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The smallest ones are B-class, followed by C, M and X, the largest. Similar to the Richter
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scale for earthquakes, each letter represents a ten-fold increase in energy output. So an
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X is 10 times an M and 100 times a C. Within each letter class, there is a finer scale
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from 1 to 9. C-class flares are too weak to noticeably affect Earth. M-class flares can
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cause brief radio blackouts at the poles and minor radiation storms that might endanger
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astronauts. It's the X-class flares that are the real juggernauts. Although X is the last
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letter, there are flares more than 10 times the power of an X1, so X-class flares can
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go higher than 9. The most powerful flare on record was in 2003, during the last solar
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maximum. It was so powerful that it overloaded the sensors measuring it. They cut-out at
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X17, and the flare was later estimated to be about X45. A powerful X-class flare like
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that can create long lasting radiation storms, which can harm satellites, and even give airline
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passengers flying near the poles small radiation doses. X flares also have the potential to
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create global transmission problems and world-wide blackouts. The seriousness of an X-class flare
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pointed at Earth is why NASA and NOAA constantly monitor the sun. NASA's Heliophysics fleet
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of spacecraft can now see the sun from every side and in many different wavelengths. This
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unprecedented coverage is enabling scientists to predict and detect space weather events
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like flares and CMEs with ever greater accuracy. With advance warning, governments and companies
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can take steps to protect their technological infrastructure, so that the worst scenarios
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will never happen. Beeping Beeping