![]() ![]() Like a sodium street light which gives off an orange light, the oxygen, nitrogen and other gases in the atmosphere have their own particular colours resulting in the range of blues, greens, yellows and reds observed in the aurora. The colour of the light depends on the molecules being excited. The excited molecule is unstable and will give up its extra energy by emitting light. When a charged particle collides with a molecule in the atmosphere the molecule becomes excited. The energy released in these collisions is given off as light. These charged particles collide with gas molecules in the atmosphere. On their way down these particles are slowed down by Earth's atmosphere, which acts as a shield. These particles sometimes travel towards Earth where they are captured by the Earth's magnetic field and guided towards the geomagnetic polar regions. ![]() Occasionally there are large explosions on the Sun, and huge amounts of charged particles are thrown out into space. The aurora is a consequence of activity on the surface of the Sun. These storms are short-lived periods of high geomagnetic activity where the Earth's magnetic field changes very quickly and strong electric currents flow high in the atmosphere. The good timing is important as the northern lights are a result of a geomagnetic storm. All you need is a dark place, a clear sky and very good timing! It is easier to see the northern lights ( aurora borealis) in the UK than you might think. Map showing likely locations where aurora will be seen as the auroral oval moves south when activity increases. The K-index values for the 3 UK observatories and the estimated global Kp is shown. Chart showing the current and recent geomagnetic activity in the UK and globally. ![]()
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