Optical Phenomena and Light in the Arctic Sky

Key Insight

The Arctic sky offers a captivating array of colors and optical phenomena. Winter skies retain the colors of dawn and dusk for hours, displaying deep violet, bruised purples, dense blues, and thin lines of yellow gold. Spring and fall bring vivid reds, oranges, and yellows through washes of rose and salmon, while summer skies have a nacreous, pastel quality. Beyond colors, a newcomer is struck by solar and lunar rings, halos, coronas, the aurora borealis, and various mirages, including fata morganas.

These phenomena are frequent due to abundant ice crystals in the atmosphere, clear air, and common temperature inversions and sharp temperature differentials at the ocean surface. William Parry’s famous 1819-20 drawing captured many effects: a sun surrounded by 44° and 92° halos, subtended by other arcs, with brilliant 'sun dogs' and a 'subsun' below. Francis M’Clintock, in 1857, observed a December moon encircled by a halo and a horizontal band, accompanied by six 'mock moons,' all rendered with a 'ghastly hue' by the misty atmosphere. The complex physics of light refraction, reflection, and diffraction explains these displays, and learning to observe them reveals 'soft, opaque white pillar[s]' or 'rainbow-hued shields'.

The aurora borealis, appearing as 'pale gossamer curtains,' is described with 'awe,' 'delicacy,' 'transparency,' and 'tremulous evanescence,' often evoking a 'spiritual presence.' Eskimos envision it as the 'play of unborn children' or 'torches held by the dead.' Scientifically, it's an electric discharge in the ionosphere, visible as energy from excited oxygen atoms (pale whitish-green, pinkish-rose) and nitrogen molecules (crimson, during intense activity). It forms in the 'auroral oval' centered on the North Magnetic Pole, created by solar wind particles following Earth's magnetic field lines. The display, often hundreds of miles long and 150 miles high, can undulate in S-curves, and its intensity can produce 1 trillion watts of power, affecting magnetic compasses, radio communications, and even pipelines. Despite anecdotal claims of sound, the aurora's most remarkable effect is its ability to draw a viewer 'emotionally up and out of himself,' transforming the sky into a profound, three-dimensional landscape that renders self-pity impossible.