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Northern Lights information ~ (Aurora borealis)

Photos, information and facts about the northern lights - scientifically referred to as the aurora borealis

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Definition of the Northern Lights (American Heritage Dictionary)

Northern Lights or Aurora: "A luminous atmospheric phenomenon appearing as streamers or bands of light sometimes visible in the night sky in northern or southern regions of the earth. It is thought to be caused by charged particles from the sun entering the earth's magnetic field and stimulating molecules in the atmosphere."

Colors and the Northern lights

  • Red and Green-Oxygen: Light emitted by the Aurora tends to be dominated by emissions from atomic oxygen, resulting in a greenish glow and in the higher altitudes the red glow.
  • Other colors-Nitrogen: Variations in color, especially those emitted by atomic and molecular nitrogen (blue and purple) vary quickly and result in dynamic movement in the aurora.

Encyclopedia: (Columbia University Press)

Northern Lights: "aurora borealis (bôr'ēăl'ĭs) and aurora australis (ôstrā'lĭs), luminous display of various forms and colors seen in the night sky.

The aurora borealis of the Northern Hemisphere is often called the northern lights, and the aurora australis of the Southern Hemisphere is known as the southern lights. Each is visible over an area centering around the geomagnetic pole of its own hemisphere.

The aurora borealis is said to occur with greatest frequency along a line extending through N Norway, across central Hudson Bay, through Point Barrow, Alaska, and through N Siberia. It is often visible in Canada and the N United States and is seen most frequently at the time of the equinoxes; in times of extreme activity, it may be seen in parts of the S United States.

Among the most magnificent of natural phenomena, auroral displays appear in shades of red, yellow, green, blue, and violet and are usually brightest in their most northern latitudes.

The aurora is seen in a variety of forms, e.g., as patches of light, in the form of streamers, arcs, banks, rays, or resembling hanging draperies.

The aurora occurs between 35 mi and 600 mi (56 km–970 km) above the earth. It is caused by high-speed electrons and protons from the sun, which are trapped in the Van Allen radiation belts high above the earth and then channeled toward the polar regions by the earth's magnetic field. These electrically charged particles enter the atmosphere and collide with air molecules (chiefly oxygen and nitrogen), thus exciting them to luminosity; near the 600-mile level, the light may be given off by electrons and protons combining to form hydrogen atoms.

The auroras coincide with periods of greatest sunspot activity and with magnetic storms (disturbances of the ionosphere which interfere with long-distance radio communication). "

Northern Lights
Green arcs just after dusk, the remnant daylight gives the enhanced blue in the sky. White Mountains National Recreation Area, Alaska. © Patrick J. Endres

Northern Lights
Green arcs over the Koyukuk river in Arctic Alaska.
© Patrick J. Endres

Northern Lights
Oxygen gasses at about 60 miles up in the atmosphere give off the common greenish glow (at a wavelength of 557.7 nm) © Patrick J. Endres

Northern Lights
Oxygen gasses at about 200 miles in the atmosphere give the dark-red glow (at 630.0 nm of wavelength). © Patrick J. Endres

Northern Lights
Blue, purple & violet colors are caused by light emitted from Nitrogen gasses. © Patrick J. Endres