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How to Assess the Solar Wind

NASA’s ACE satellite keeps constant track of the solar wind. Located a million miles above the earth’s surface, this satellite gives us about an hour’s advance warning of impending space weather storms. The ACE satellite measures the speed of solar wind particles, the number of particles (density), and the strength and orientation of any embedded magnetic fields.

Check the current data for yourself. The following are indicators of possible severe space weather: particle speed greater than 600 kilometers per second (km/s), particle density higher than 20 per cubic centimeter (cm3), and vertical magnetic field (Bz) less than -10 nanoteslas (nT) [units not shown on the graph].

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