1452 NORWAY (Svalbard) - An aurora borealis seen from Svalbard archipelago

Nature gives us a lot of amazing performances, but none is so impressive, mysterious and beautiful as the aurora, a show of light and color that can be seen on the sky of the Arctic and Antarctic regions. Those who lived this experience say it can't be compared with anything in the world, and the photos seem to give them right. Scientifically speaking, an aurora is a natural light display in the sky, caused by charged particles, mainly electrons and protons, entering the atmosphere from above causing ionisation and excitation of atmospheric constituents, and consequent optical emissions. When it occurs in the northern hemisphere (from September to October, and from March to April), the phenomenon is known as the aurora borealis (or the northern lights), a term originally used by Galileo Galilei, referring to the Roman goddess of dawn, Aurora, and to the Titan who represent the winds, Boreas.

Auroras take many different visual forms. The most distinctive and brightest are the curtain-like auroral arcs. They eventually fragment or ‘break-up’ into separate, and rapidly changing, often rayed features which may fill the whole sky. The composition and density of the atmosphere and the altitude determine the possible light emissions, and the color of them (red, green, yellow, pink and blue). The most common are the green ones, which occur at lower altitudes. Photographic film has a different sensitivity to colors than the eye, therefore you often see more red aurora on photos than with the unaided eye. Actually the colors that we see are a mixture of all the auroral emissions, as the white sunlight is a mixture of the colors of the rainbow. The overall impression is a greenish-whitish glow. Very intense aurora gets a purple edge at the bottom, which.is typically at 100km altitude.

Aurora borealis from the postcard was photographed in the Svalbard archipelago (formerly known by its Dutch name Spitsbergen), which range from 74° to 81° north latitude, at about midway between continental Norway and the North Pole. In the foreground are seen dog sleds, commonly used for hunting and travel in Arctic region until the appearance of snowmobiles. The building towards which go the crews is a lodge in the Advent valley.

About the stamps
The first stamp, depicting a polar bear, was custom made for Svalbard and was sold in Svalbard only.

The second is part of the series Active Holidays, designed by Gina Rose and issued on April 19, 2013:
• Ice climbing on the Jostedal Glacier (A Domestic)
• Bøya Glacier, arm of the Jostedal Glacier (A Domestic)
• Hiking at Mount Gaustatoppen (A Europe) - It's on the postcard
• Hiking at Mount Gaustatoppen (A Europe)
• Rafting on the Sjoa River (A Worldwide)
• Riverboarding on the Sjoa River (A Worldwide)

References
Aurora - Wikipedia
Frequently Asked Questions about Aurora and Answers - Frequently Asked Questions about Aurora and Answers

Sender: Tone Nor
Sent from Longyearbyen (Svalbard / Norway), on 03.02.2015  
Photo: Tommy Simonsen