The mystery of the Northern lights
Surrounded by the mystery of former times, this is at present the object of sound curiosity among most people and of deep interest to researchers.
Educational examples give insight into the research into the northern lights, popular belief and mystery, forms of northern lights and images.
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| The mystery of the Northern lights |
| As an enormous, twinkling shining curtain in yellow and green against the large black sky in the north. This is a form of the northern lights, a phenomenon that people have wondered about through the ages. |
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| History and description |
| The Norwegian researcher Kristian Birkeland presented at the turn of the century the first theory as to how the phenomenon arises. |
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| History, popular belief and mysticism |
| Northern lights concern nature, physics and natural science - but are also part of cultural history. Through thousands of years stories, myths and notions have been associated with the phenomenon called northern lights, fascinating researchers, people in general and artists alike. |
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| The Earth’s atmosphere, colours and forms of northern lights |
| The northern lights may be observed because the sun wind particles arrive into the atmosphere and energize (leaving its usual, lowest energy condition into a condition of higher energy) atoms and molecules they meet. These atoms and molecules send the energy out again in the form of a light of certain colours |
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| Research |
| The Andøya Rocket Range on Andøya island in Norway has, for a long time, been a cornerstone in groundbased research of the northern lights. |
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| Northern and Southern lights are different |
| Norwegian researchers are involved in the discovery of the difference between Northern and Southern lights, or aurora borealis and aurora australis. |
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| The importance of the direction of the magnetic field in the sun-wind |
| Use the knowledge programme “The Northern Lights” as a means to understand the sun-wind and the direction of the sun-wind field. |
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| The ACE satellite measures the sun-wind |
| The ACE – Advanced Composition Explorer is an American satellite having as its main purpose to measure the sun-wind. The ACE is placed in an orbit around the L-1 point (the Lagrangian point) between the Earth and the sun. Here observations are made of the sun-wind and the atomic particles. |
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| The POES satellites and the northern lights |
| NOAA POES-satellites is a group of polar orbit satellites from the National Oceanic Atmospheric Administration (NOAA) in the USA. They survey among other things weather and climate. The satellites pass over the North Pole and the South Pole, thus passing above areas where northern lights may be observed. |
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| Magnetometer measurements and the northern lights |
| The northern lights are formed when electrically charged particles collide with the atoms in the atmosphere so that these start shining. Where the electrically charged particles drop down, electrical currents are also formed high up in the atmosphere. These currents may be measured by measuring alterations of the magnetic field down here on the ground. |
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| All-sky camera |
| An "All-sky"-camera is, as the name implies, a camera with which you may take pictures of the whole sky simultaneously. This may be obtained by using a "fish-eye" lens or systems with a convex mirror. Several cameras have a filter that makes it possible to see only one special wavelength (colour) of the lights. |
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| Calculation of time delay from the ACE: example from 25.10.2007 |
| On the 25th October 2007 a rather sudden alteration of the sun-wind was registered by ACE. The true time data from the ACE is shown in the figure below. We may here see that the density, speed and temperature make a jump at 10.40 UT. |
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