aurora borealis


Also found in: Dictionary, Thesaurus, Medical, Acronyms, Wikipedia.

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.
..... Click the link for more information.
; 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
..... Click the link for more information.
 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 ?
The best chance to see the Aurora Borealis is during clear, cold and cloudless nights, far away from light pollution.
He was previously the director of NOAA'S Space Weather Prediction Center, which is the nation's official source for space weather alerts, watches, and warnings--including forecasts of the aurora borealis and australis.
Calmly, she said, "Oh that's the aurora borealis, the northern lights."
Yet tensions were already evident as anomalous knowledge claims about the Aurora Borealis emerged into a cultural and social context in which western publics began to be made aware of the ways in which aurorae, just like the weather, could not easily be made orderly by scientific and intellectual authorities.
At TimeframeHD Joel Shat's work is presented in the following collections: Night Sky, North America, Winter, Aurora Borealis, Lakes and Rivers, Forest, Mountains and other collections.
The aurora borealis was seen at the observation site.
Yellowknife is a popular destination choice for Aurora viewers as the city is located directly under the Aurora Oval, a narrow band encircling the polar reaches of the earth and provides the most brilliant colours from the Aurora Borealis. Yellowknife also provides other attractions, such as culture and shopping.
16 April 2012 a[euro]" US virtual pre-paid cards provider Friendgiftr said it had struck a deal that would make it the property of US private equity group Aurora Borealis Investments LLC.
Summary: New stunning videos of the Aurora Borealis shown from space, have been released by Nasa.
Aurora Borealis Pass over the United States at Night
People in Northern Ireland were able to spot displays of the Northern Lights (aurora borealis) when they appeared farther south than usual earlier this week.
The company has offered holiday packages that will offer travellers an opportunity to experience the phenomenon of Aurora Borealis. Packages offered by the company include accommodations and various activities like hunting for the Northern Lights or Aurora Borealis, dog sledding and reindeer sledding trips, horseback riding, snowshoeing, skiing, snowmobiling and fishing.