The dancing Northern Lights explained
Tuesday, July 29th, 2008
The Northern Lights can be
seen on our winter holidays
in Finland.
The mythical and certainly magical Northern Lights or Aurora Borealis form curtains of light across the night skies of the northern (and southern) polar regions. It is often thought that these veils of colour can come close to Earth but until just a few days ago there was only speculation about how they moved across the sky and at times burst into colours.
A year or so ago NASA launched 5 satellites called THEMIS to study aspects of the magnetosphere. They now believe that the movement or dancing of the Northern Lights known as substorms, are formed initially in the Earth’s magnetic field around 1/3 of the way to the Moon. Here these magnetic field lines are interupted by the Sun’s solar winds and when they snap back into place, just as poles of two magnets would, this sends charged particles back towards Earth. These reconnections thus cause an increase in intensity and expansion of the Northern Lights and ultimately the re-distribution of the electrical currents flowing in space around our planet. To understand more about this fascinating and beautiful phenomenon you can enjoy a talk by a scientist from the Geophysical Institute in Sodankyla in northern Finland on our ‘Searching for the Northern Lights’ holiday short breaks.



