Space Weather Alert - 19-21 December 2014

What Has Happened?

 

There are two notable events this weekend, as Coronal Mass Ejections (CMEs) are expected to arrive at Earth on the evening of 19 December and during the day on 21 December.

Firstly, a the arrival of a glancing blow from a CME that left the Sun on 17 December is anticipated late on the 19th of December, and is expected to increase geomagnetic activity levels, though perhaps not to the extent required for auroral displays anywhere but in the far North of Scotland.

Secondly, an M Class X-ray flare (M-6) and associated CME occurred late on Thursday 18 December. This CME is predicted to arrive at Earth around, or shortly after, noon on the 21st, and is expected to increase global geomagnetic activity levels to a greater degree than predicted for the impact on 19 December.

Assuming clear dark skies, there is an increased chance of seeing the aurora in the hours following the arrival of the CMEs, particularly on the night of the 21st of December. This is especially true for those in the North of Scotland.

 

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Glossary

BGS

The British Geological Survey is one of the Natural Environment Research Council's Research Centres.

CME or Coronal Mass Ejection

The eruption of a portion of the outer atmosphere of the Sun into space, caused by rapid changes in its magnetic field. Often occurs along with a solar flare.

 

Solar Flare

Energy released by the explosive reorganisation of magnetic fields within the Sun's atmosphere.

Solar Wind

The ever-present expansion of the Sun’s hot outer atmosphere into the solar system, which carries space weather within it.

Sunspot

A region of intense magnetic field in the Sun's visible outer atmosphere often associated with flares and CMEs.