aurora borealis


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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 equinoxesequinox
, either of two points on the celestial sphere where the ecliptic and the celestial equator intersect. The vernal equinox, also known as "the first point of Aries," is the point at which the sun appears to cross the celestial equator from south to north.
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; 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 beltsVan Allen radiation belts,
belts of radiation outside the earth's atmosphere, extending from c.400 to c.40,000 mi (c.650–c.65,000 km) above the earth. The existence of two belts, sometimes considered as a single belt of varying intensity, was confirmed from information
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 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). Much was learned about the aurora during the 1957–58 International Geophysical Year, when it was studied intensively by means of balloons, radar, rockets, and satellites. Other planets in the solar system also have auroras.

aurora borealis

[ə′rȯr·ə ‚bȯr·ē′al·əs]
(geophysics)
The aurora of northern latitudes. Also known as northern lights.

aurora borealis

The ghostly display of lights in the form of streamers, rays, arcs, bands, curtains, sheets or patches that seem to shimmer and flit across the sky in the Northern Hemisphere. These are most common in higher latitudes centering around magnetic poles. They are associated with magnetic storms on the sun, which appear as sunspots. Also called northern lights.

aurora borealis

the aurora seen around the North Pole
References in periodicals archive ?
From the magnificent sketches and paintings of artists and scientists on these Arctic expeditions to the visual spectacles enjoyed by the public at metropolitan panorama shows and in illustrated newspapers, the Aurora Borealis became a crucial component in the nineteenth-century construction of the Arctic as a "dreamland," to use Fridtjof Nansen's telling description.
1,000km THE height at which the aurora borealis can occur although most are between 80km and 120km
In the past, researchers thought that the aurora borealis was too far away for people to hear the sounds it made," said Professor Unto K.
The acquisition by Aurora Borealis Investments is proof that Friendgiftr has been on the right track and the deal is an exciting opportunity for the young company, Carpenter added.
The Aurora Borealis can be seen above Earth's northernmost and southernmost regions.
The company has offered holiday packages that will offer travellers an opportunity to experience the phenomenon of Aurora Borealis.
Mrs B Albrighton, Warks 2BECAUSE of its location in the far north of Britain and the lack of light pollution, the Shetlands are a perfect place to see the aurora borealis.
THE AURORA BOREALIS, OR northern lights, is one of the most spectacular phenomena to grace our night skies, producing spectacular coloured curtains of electric light that appear to shimmer and shake in the freezing air.
Chaplin describes in detail Franklin's other achievements, including charting the Gulf Stream and describing the aurora borealis, and argues that if not for his foray into U.
There are also Swarovski crystal sinks that feature hand-placed Swarovski crystals and come in pink, black, blue, turquoise and aurora borealis.
Imagine a monastic hut from a Sung dynasty scroll transplanted onto a slab of molten lime bubble gum with a pea soup base, a riotous aurora borealis behind, and a magenta abyss in front.
However, with his masterful new film about the aurora borealis, Picture of Light, a breathtaking investigation of the powers and limits of film language, Mettler should assume his rightful, prominent place in contemporary Canadian cinema.