Stig Östlund

onsdag, augusti 04, 2010

GEOMAGNETIC STORM

A geomagnetic storm that sparked auroras over Europe earlier this evening is subsiding--but it could flare up again if another CME arrives. High-latitude sky watchers should remain alert for auroras.
The action began on August 3rd around 1740 UT when a CME hit Earth's magnetic field. The impact caused a moderate geomagnetic storm (Kp=6) and auroras over northern Europe. At the height of the display, Jesper Grønne of Denmark took this picture:





"It's not every day we see auroras at +56 degrees latitude," says Grønne.

While the sky pulsed with color, electrical currents ran through the ground. In Lofoten, Norway, aurora researcher Rob Stammes detected strong currents in the earth outside his laboratory: data. "A current surge at 17.40 UT indicated the arrival of the CME," he says. "The geomagnetic storm began shortly thereafter."
All this activity was prompted by the complex solar eruption of August 1st. Analysts believe that multiple explosions may propelled not just one but two CMEs in our direction. If so, a second cloud could arrive soon and re-energize the storm. Stay tuned!

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