Auroral lights bedazzle both polar ends

An unexpectedly strong solar storm combines with earthly particles to create amazing light displays above two poles.

| | Environment, Science & Technology, Weather

Solar storms rumbling away on the surface of the sun has resulted in a spectacular auroral display over earthly skies during the weekend with sightings over North America and Northern Europe.

But observers in Australia and New Zealand were also bedazzled by auroras in their skies.

The auroras, surrounding both the north magnetic pole [aurora borealis or northern lights] and south magnetic pole [aurora australis] occur when highly charged electrons from the solar wind interact with elements in the earth's upper atmosphere - usually over 100km above the earth's surface.

The collision of these particles cause neutral atoms to fluoresce, emitting light of different wavelengths.

The most common colours are green and red.

The colour of the aurora depends on the altitude where the collisions  with oxygen and nitrogen atoms take place in the upper atmosphere.

The US observers at National Oceanic and Atmospheric Administration (NOAA) said the G4 solar storm was the result of two coronal mass ejections, or CMEs, observed leaving the sun on March 15 - there were two blasts of magnetic plasma or erupting solar flares.

These reached the earth's atmosphere about 48 hours later in the form of the auroral displays.

The storm was rated severe - a 4 on NOAA’s 5 point scale for geomagnetic effects, the strongest to hit earth in the past 18 months and stronger than predicted by the scientists, who had expected a level 1 storm to graze by.

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