Each time the sun hurls a planet-size cloud of charged particles toward Earth, there's a potential for power outages and satellite damage. But it's when the magnetic field carried by these billion-ton clouds points opposite to Earth's magnetic field that geomagnetic storms are most severe. In that configuration, our planet's field, which usually shields Earth from the sun's outbursts, connects directly to the field accompanying the cloud. That magnetic handshake opens up a hole in Earth's shield, permitting energetic ions and electrons from the sun to gush through and induce large electrical currents in and around the planet.
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