The Earth just missed being hit last Monday by a powerful blast of radiation discharged by a huge flare on the sun's surface.
The flare was associated with a massive cluster of sunspots which had cleared the face of the sun that points towards our planet.
Most of the energy from the "superflare", the largest recorded in 25 years, sailed harmlessly past into space. Radio transmissions were temporarily disrupted however in an "R4 radio blackout" that disturbed shortwave transmissions including radio contacts with aircraft.
The flares are thought to occur when distortions in the sun's complex magnetic field release their energy in massive explosions equal to the bang that would be caused by billions of tonnes of TNT. Flares come and go in an 11year cycle and the sun is only just exiting "solar maximum" when flares occur most frequently.
"We were perhaps lucky that this event didn't occur over the weekend, when the resulting [flare] would almost certainly have been aimed towards Earth," said Dr Paal Brekke, the European Space Agency deputy project scientist for the SOHO spacecraft, which monitors solar activity.
These flares, or coronal mass ejections, throw billions of tonnes of charged particles out into space. The particle cloud can cause problems on earth and also lights up the northern sky with a display of the aurora borealis or northern lights.
Flares can cause surges along power lines, leading to blown transformers. Quebec was blacked out after a large such flare several years ago.
The flares can damage the sensitive electronics in communications satellites and the flare energy distorts the earth's ionosphere which can knock out certain radio frequencies in the shortwave range, including radio links with aircraft.
