Polar Nights

Folklore has several explanations of the origins of the spellbinding lights that can be seen best during Kaamos time (Kaamos = the dark months in Lapland). In Finnish they are called "revontulet", which means "fox fires" a name derived from an ancient fable of the arctic fox starting fires fire or spraying up snow with its brush-like tail. The true story is that the sun is the mother of the auroras.

The sun gives off high-energy charged particles (also called ions) that travel out into space at speeds of 320 to 704 kilometres per second. A cloud of such particles is called a plasma. The stream of plasma coming from the sun is known as the solar wind. As the solar wind interacts with the fringes of the earth's magnetic field, some of the particles are trapped by it and they follow the lines of magnetic force down into the ionosphere, the section of the earth's atmosphere that extends from about 60 to 100 kilometres above the earth's surface. When the particles strike the gases in the ionosphere they start to glow, producing the spectacle that we know as the auroras, northern and southern. The variety of colours, red, green, blue and violet that appear in the sky corresponds to the different gases in the ionosphere.

The Northern Lights are constantly in motion because of the changing interaction between the solar wind and the earth's magnetic field. The solar wind commonly generates up to 100,000 megawatts of electricity in an auroral display and this can cause interference with power lines, radio and television broadcasts and satellite communications. By studying the auroras, scientists can learn more about the solar wind, how it affects the earth's atmosphere and how the energy of the auroras might be exploited for useful purposes.

Christmas eve at Lapinjärvi church yard.