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Post by Charity on Jan 5, 2006 13:57:28 GMT -5
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Post by Charity on Jan 5, 2006 14:03:36 GMT -5
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Post by Charity on Jan 5, 2006 14:07:46 GMT -5
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Post by Charity on Jan 5, 2006 14:10:13 GMT -5
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Post by Charity on Jan 5, 2006 14:26:50 GMT -5
pretty
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Post by Charity on Jan 5, 2006 14:28:57 GMT -5
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Post by Charity on Jan 5, 2006 14:30:42 GMT -5
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Post by Charity on Jan 5, 2006 14:31:35 GMT -5
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Post by Charity on Jan 5, 2006 14:35:24 GMT -5
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Post by Charity on Jan 5, 2006 14:41:03 GMT -5
Legends and Folklore of the Northern Lights The aurora borealis has intrigued people from ancient times, and still does today. The Eskimos and Indians of North America have many stories to explain these northern lights. One story is reported by the explorer Ernest W. Hawkes in his book, The Labrador Eskimo: The ends of the land and sea are bounded by an immense abyss, over which a narrow and dangerous pathway leads to the heavenly regions. The sky is a great dome of hard material arched over the Earth. There is a hole in it through which the spirits pass to the true heavens. Only the spirits of those who have died a voluntary or violent death, and the Raven, have been over this pathway. The spirits who live there light torches to guide the feet of new arrivals. This is the light of the aurora. They can be seen there feasting and playing football with a walrus skull. The whistling crackling noise which sometimes accompanies the aurora is the voices of these spirits trying to communicate with the people of the Earth. They should always be answered in a whispering voice. Youths dance to the aurora. The heavenly spirits are called selamiut, "sky-dwellers," those who live in the sky. www.ewebtribe.com/NACulture/articles/aurora.html
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Post by Charity on Jan 5, 2006 14:43:39 GMT -5
High season for Auroras By John Bird Special to the Sun Some of nature's most beautiful displays are best seen at the South Pole - halos, sun dogs, sunsets and stars. The most spectacular is the aurora, a dancing light show of colorful bands in the night skies at high northern and southern latitudes. Auroral displays are the icebergs of the thermosphere, sculpted by solar wind, floating in waves of atomic oxygen, bestowing their alluring and ethereal brilliance. Robert Scott said, "It is impossible to witness such a beautiful phenomenon without a sense of awe, and yet this sentiment is not inspired by its brilliancy but rather by its delicacy in light and color, its transparency, and above all its tremulous evanescence of form." This season will be an excellent one for the aurora because we are near the peak of the 11-year solar cycle. The best place to observe the aurora is under the auroral ovals, the donut shapes of the aurora around the north and south magnetic poles. These rings surround the north and south magnetic poles and may be easily seen from space. The auroral oval nearly goes over the South Pole, and also is near McMurdo Station. In the northern hemisphere, the auroral oval goes over Alaska and northern Canada. So if you are wintering, or heading back to Alaska as many people on the Ice are, you are very lucky. Although auroral displays most frequently occur in northern latitudes of 65 to 70 degrees, they sometimes occur at lower latitudes. I've seen many excellent displays at 44 degrees north latitude. People have always been curious about the aurora, citing it in folklore and mythology throughout the ages. For example, a famous display was seen in India and Egypt during 1872. Very low-latitude auroras are usually red. In 1938 such a display was chased by a fire brigade sent out to extinguish a fire at Windsor Castle in London. Scientific studies of the aurora also date a long way back, specifically to 1621 and a French scientist named Gassendi. He documented his observations in a physics book in which he referred to what he saw as the aurora borealis, meaning northern dawn. In 1773 the corresponding phenomenon in the Southern Hemisphere, aurora australis (southern dawn), was first reported by Captain Cook. He observed it when he sailed the Indian Ocean. The aurora is popularly known as northern or southern lights. By 1873 the northern auroral zone was mapped and was found to be a ring around the north magnetic pole. Spectral measurements, that is, measurements of the component colors, were initially made in the early 1900s. An international campaign during 1957-58 was organized to study the aurora. This led to our current general understanding of the aurora, but there are still many unanswered questions. The aurora appears in many different forms: arcs with rays, bands, pulsating surfaces, and draperies. One of the most common forms is a blue-green flickering drapery moving across the northern sky. Narrow, vertical, luminous columns with rapid fluctuations in intensity are common. The lower border is often intense and sometimes red. Typically, a display lasts a few minutes and occurs a few times per night. Strangely enough, there have been numerous reports of people hearing the aurora, although there is yet no scientific explanation or confirmation. To understand the aurora, we must start at the Sun. Above the surface of the Sun, a complex interaction of radiation and convection maintains the gaseous region called the corona. At temperatures over a million degrees Celsius, the corona continuously gives off particles collectively forming the solar wind. When the solar wind reaches Earth, it interacts with Earth's magnetic field, causing electric currents to travel along the magnetic field lines. Much like a magnet, these field lines converge at the polar regions, directing the electric currents to the ionosphere in the polar regions. The electrical power is converted to light in the ionosphere rather like a neon sign by exciting atomic oxygen and nitrogen into higher energy metastable states. When the electrons return to the ground state, the photons are emitted. The colors are characteristic of the components of the atmosphere and the altitude. Most auroras are from a form of atomic oxygen called singlet S, which describes the shape of the electron shell giving off the characteristic green color. A higher energy state of oxygen, singlet D, gives off red. Other colors are from nitrogen. The lowest part of the aurora is usually at about 62 miles (100 kilometers) in altitude. The most spectacular auroral displays are caused by bursts of solar wind particles originating from magnetic storms on the Sun. These particles reach Earth directly from the Sun and from the far regions of the magnetosphere which streams beyond the Earth, away from the Sun, forming the magnetotail. Earth's magnetic and electric fields in space guide and accelerate particles toward the auroral regions. The power created by a magnetic storm hitting the ionosphere is about half due to particles and about half due to electric currents. Here at the Atmosphere Research Observatory at the South Pole, the Aurora All Sky Imager experiment will operate an intensified optical, all-sky imager, operating in several wavelengths. The imager allows us to study waves in the atmosphere, to look at various altitudes, and to discriminate between types of electron precipitation. The principal investigator for the experiment, Gary Swenson of the University of Illinois, is a veteran of many auroral investigations around the world. John Bird, B.Sc, M.A.Sc., Ph.D., P. Eng., FBIS, is wintering at South Pole Station to study the southern auroras. www.polar.org/antsun/oldissues2000-2001/2001_0204/auroras.html
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Post by Charity on Jan 5, 2006 14:45:19 GMT -5
Aurora Borealis - It’s often called the "northern lights". It occurs 50 to 100 miles above the earth, when energetic particles from a solar storm cause the gases in the upper atmosphere to glow. Auroras can last between a few minutes to several hours. It’s common across Alaska and northern Canada. more on weather here at Weather Whiz Kids www.weatherwizkids.com/Weather%20Words.htm
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