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Get ready for a second blast
Posted: 04 August 2010

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The first of two coronal mass ejections blasted out from the Sun at the weekend arrived in Earth's neighbourhood last night, lighting up the skies across Europe and North America. A second blast is expected to arrive tonight.

Almost the entire Earth-facing side of the Sun erupted on 1 August, blasting out two coronal mass ejections. The different colours in this extreme ultraviolet snapshot from the Solar Dynamics Observatory represents different gas temperatures ranging from 1 to 2 million degrees K. Image: NASA/SDO.

Last night's activity rated G2 on the NOAA Space Weather Scale for Geomagnetic Storms, translating as a moderate storm on a scale that tops out at grade five. The storm struck the Earth's magnetic field at 1740 UT and persisted for some 12 hours.

These images taken by the STEREO Ahead satellite from 3:47 to 15:47 UT, show the movement of the CME cloud, on the right of the discs, as it expands toward Earth. Image: NASA/STEREO.

A second bout of geomagnetic activity is forecast for this evening; according to, there is a 35 percent chance of major geomagnetic storms. You can see some of the beautiful auroral displays from last night's storm in's aurora gallery.

Read yesterday's report, Solar blast heads for Earth, here.