A former guest lecturer on our Arctic Explorer journey, Ian Ridpath (FRAS), explains how to successfully see the Northern Lights.
“No pencil can draw it, no colours can paint it, and no words can describe it in all its magnificence,” according to the 19th century polar explorer Julius von Payer. He was referring to the Aurora Borealis, popularly known as the Northern Lights, one of the wonders of the natural world, and one of the top items on many people’s bucket list.
Aurorae are a phenomenon of the polar skies, so you need to go north to places such as Alaska, Canada, Scandinavia or northernmost Russia to have the best chance of seeing them. To the inhabitants of these areas, aurorae are a familiar sight during the long polar nights. Inevitably, many superstitions grew up about these ethereal lights. They were, according to various myths, the spirits of the dead, light emitted from glaciers, or perhaps sparks from the tail of an Arctic fox as it scampered over the snow. In Russia, they were associated with the fire dragon Ognenniy Zmey, and indeed the writhing shapes of some aurorae do look remarkably dragon-like.
Modern science tells us that, in reality, these fantastic lights are glows in the Earth’s upper atmosphere, at heights between about 60 and 150 miles. But their cause lies 93 million miles away – the Sun.
Streams of atomic particles, called the solar wind, flow away from the Sun’s surface at high speed. When they reach the Earth these particles are deflected by the Earth’s magnetic field so that they cascade down onto the upper atmosphere in a ring around the magnetic poles, both north and south. There, they interact with atmospheric gases and cause them to emit light – usually green, but also red and sometimes purple too.
Do not, however, expect to see with your eye the strong colours that appear on photographs, because the human eye is not very sensitive to faint light. You will see some colour, but it will most likely be a shimmering grey-green.
The main beauty of aurorae lies in their ever-changing shapes, which morph from arcs and flowing bands to towering curtains that ripple like drapery in a breeze. Most magnificent of all is a corona, a starburst effect caused when the display is directly overhead and the sheets of light seem to converge above you like the apex of a tent.
Aurora come and go during the night with little regard for human watchers, so patience is required, although they are most common for an hour or so either side of midnight. A display can last from a few minutes to several hours, and at best it can cover the sky.
Good aurora hunting!
For more information about the aurora, including tips on photographing it, click here