Solar flares herald rare glimpses of northern lights over UK.

Source: http://www.guardian.co.uk/science/2011/feb/17/solar-flares-northern-lights-uk

Date: Thursday 17 February 2011

The surface of the Sun (above) erupts with dazzling solar flares that form giant, glowing loops reaching tens of thousands of kilometres into space.

Solar flares are the most violent explosions in the solar system and each releases as much energy as a hundred million hydrogen bombs. Earth-sized regions of the Sun’s corona soar to temperatures of 20 million Celsius during the convulsions.

This image, captured by Nasa’s Solar Dynamics Observatory (SDO), shows a storm brewing on the surface of the Sun over the past week. On Tuesday, satellites recorded the most powerful solar flare in four years erupting from a massive sunspot.

The storm generated at least three solar flares, the most intense of which was detected at 1.56am GMT on Tuesday. The x-class flare, the most powerful of all solar events, came from a growing active region called 1158 in the Sun’s southern hemisphere.

The bright flashes were accompanied by coronal mass ejections, which blasted billions of tonnes of material towards the Earth at 900 kilometres a second. The rush of particles could light up the night sky with a spectacular aurora borealis, but cloud cover and the brightness of the moon may obscure the view.

The British Geological Survey said displays of the northern lights had already been seen further south than usual, in Northern Ireland and elsewhere in the UK. The celestial light show occurs when cosmic particles hit the upper atmosphere and are steered to the poles by the Earth’s magnetic field, colliding with other particles.

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