Dancing Skies over Antarctica
During the winter months on the Antarctic continent not only do we experience 24 hour darkness but we are privileged to see the aurora australis. Here at Halley Station we were looking forward to experiencing many a night gazing at the dancing lights as they flitter across the sky. Reading the small print however, revealed that there is a cycle of activity that revolves around an 11 year period. It seems that 2009 is a low solar activity year and hence our expectations might have been a bit high.
Large flares or solar explosions from the sun will expel numerous amounts of solar particles which make their way towards Earth. These particles come into contact with the Earth’s magnetosphere and are directed towards the polar regions. High energy particles then cascade into the highest parts of the Earth’s atmosphere, ionising gases. It’s this process that emits the glows that we see on Earth. The variation of colour is a result of particles with different energies ionising different gases.
