Aurora polaris

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					Aurora polaris
Aurora polaris (aurorae) is a physical phenomenon that occurs when solar wind is more
powerful than normal, with a large electrical discharge that winds electrically charged
particles toward Earth. The particles are electrons and protons which forms the light when
they collide with gases in Earth's atmosphere. Polar Lights is located at a height of between
90 and over 180 km above the ground. The phenomenon can be observed in the night sky in a
belt around the magnetic poles. Aurora emerges as an undulating light that varies in form,
color and strength, from dark blue drop the green and yellow, to red and orange.

Aurorae in the northern hemisphere is called aurora borealis (means dawn in the north) or
Northern Lights, While the aurorae in the southern hemisphere is called aurora australis or
sørlys.

Norway participates actively in international auroral research, including through Andøya
Rocket Range.

Colors
Polar Lights contains only certain specific colors, ie not all the colors in solspekteret. This is
because the polar light is created through exposure in various specific wavelengths of atoms
and ions in the atmosphere. This is done in connection with these atoms and ions in the
atmosphere is hit by the solar wind, the stream of particles from the sun. This leads to a
eksitasjon of atoms, and they emit light at specific wavelengths. The colors are mostly from
excited nitrogen molecules, nitrogen molecular ions and oxygen atoms. The color of the polar
light depends on how high in the atmosphere phenomenon occurs.

Over 180km - Nitrogen molecules and oxygen atoms to create a red light.

Between 120km and 180km - Oxygen Atoms creates strong gulgrønt light.

Under 120km - Nitrogen Molecular Ions creates mauve light.

History and research on aurorae.
The first realistic description of the aurora was in the famous Norwegian Chronicle
Kongespeilet from approx. year 1230 Here the author had mentioned three theories for why
we see the northern lights. Later, during the period 1550-1800 was especially priests in
Norway, who wrote about the Northern Lights. In 1724, the first thesis which was entirely
devoted to the Northern Lights phenomenon written by the Norwegian Jens Spideberg.

Later, several researchers tried to find out more about the strange phenomenon aurora.
Around the year 1900, it was possible to explain the aurora something like we do today. This
explanation is formed on the basis of Tromholts investigations, where he found the
relationship between the aurora and sunspots, and Birkeland Terrella experiments.

The explanation went out on the charged particles from the sun is controlled by Earth's
magnetic field and the "teeth" atmospheric gases. At that time, they could not explain how the
gases in the atmosphere was "lit" and how the different colors of the aurora occurred. When
Dane Niels Bohr presented his atomic model in 1913, it became possible to make such an
explanation. In the 1920's was the height of the aurora mapped the storm.

One of the most internationally renowned Norwegian aurora scientists are Lars Vegard.

Northern Lights Research is still ongoing in Norway and in many other countries. This
research provides and has provided us with new information about the sun, the earth's
atmosphere and on the immediate outer space. An example of a place in Norway where the
research on the Northern Lights, is the rocket launch field at Andøya. From the ground, one
can only study the northern lights from below, and from satellites, you can study it from
above. But with the help of rockets, one can make measurements in the northern lights.




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posted:2/16/2010
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