VIKING berserkers were said to have taken hallucinogenic mushrooms to help whip themselves into a frenzy before battle. They certainly wouldn鈥檛 have needed them to see trippy light patterns in the sky.
In Earth鈥檚 polar regions 鈥� such as here, in Nordland county, Norway 鈥� natural light shows occur when charged particles from space surge into the high atmosphere and collide with atoms. The result is the famous Northern Lights, or aurora borealis.
If the light is red, you know nitrogen atoms have been zapped. But usually the light is green, which means oxygen atoms 80 kilometres above ground are emitting photons as they calm down from their excited state.
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鈥淭his is a special shot for me,鈥� says photographer Arild Heitmann, 鈥渟ince it captures the intense feeling of standing deep in the mountains, far away from light pollution, watching the finest light show on the planet.鈥� The shot won Heitmann runner-up prize in this year鈥檚 Royal Observatory Astronomy Photographer of the Year competition (see other winning photos at ).
People living in temperate regions don鈥檛 often get to see the show. But when there is particularly violent solar activity, the oval zone of the aurora enlarges until it can be seen at lower latitudes. In 1859 鈥� not quite coinciding with the publication later that year of On the Origin of Species 鈥� there was a massive solar flare that was seen around the world. that the subsequent aurora was 鈥渟o brilliant that at about one o鈥檆lock ordinary print could be read by the light鈥�.
It was caused by a huge coronal mass ejection, when solar wind and particles burst from the surface of the sun. We are not alone in experiencing the results of solar storms: Jupiter and Saturn, both with magnetic fields much stronger than Earth鈥檚, have their own magnificent auroras.