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Iceland
is very well placed for aurora viewing. Around the poles are so called
"Aurora Ovals" which are belts around the geomagnetic poles where auroras
are formed. These belts vary in size according to the strength of the solar
winds that cause the auroras. Iceland is in the most active part of the
Aurora Oval in the northern hemisphere which means that auroras can almost
always be seen as long as there is clear sky.
The Aurora Borealis or Northern Lights is undoubtedly one of the most
spectacular and beautiful of nature's phenomena. In classic mythology,
Aurora was the Roman goddess
of the dawn; while "boreal" is a Latin word, meaning
"north." The southern hemisphere's
equivalent of the Northern Lights is the Aurora
Australis.
What are Northern Lights?
 To
scientifically understand the auroras, we must turn to the Sun. Inside the
Sun is a burning nuclear furnace, that will continue to burn for at least
five billion years. The Sun's powerful magnetic fields can break through the
suns surface and form dark areas known as sunspots. When the Sun is at the
peak of its 11-year cycle, the Solar Maximum, the sunspots increase in size
and number. These sunspots are the source of massive eruptions known as
solar flares that blast out billions of tons of charged particles that race
through space as solar wind. At speeds ranging from 300 to 1000 kilometers
per second the solar wind commonly takes two to four days to travel the 93
million miles to earth.
The particles penetrate the Earth's magnetic field and are guided down into
the ionosphere along the lines of the magnetic field around the poles. At an
altitude of between 60 and 400 miles, the particles strike the gases in the
ionosphere, causing them to glow and thus form the aurora.
Where do Northern lights occur?
The Northern Lights, as the name suggests, are
therefore mostly limited to the Polar Regions. They occur most frequently in
a 2500 km radius centered on the geomagnetic pole. This so-called auroral
zone extends over northern Scandinavia, Iceland, Greenland and continues
over northern Canada, Alaska and along the coast of Siberia.
The best season for Northern Lights viewing
In the Northern Hemisphere the best time of year
for viewing the aurora is the period from September through March. In the
summertime the aurora cannot be seen because of the long daylight hours.
Colors of the Northern Lights
 The
auroral colors correspond to the different types of gases in the ionosphere.
Oxygen atoms give off red and green light, depending on how high they are in
the ionosphere; whereas nitrogen molecules give violet light. The most
common color observed is green.
For how
long can the Northern lights been seen?
During a moderate to large auroral display, which
can last up to three hours, the amount of energy released is roughly
equivalent to that of a small nuclear explosion. Typically, a display lasts
a few minutes and occurs a few times per night. Auroral activity is usually
highest during the hours near midnight, when the widest part of the auroral
oval passes over the observer.
Light-pollution, particularly city lights, can dramatically reduce
visibility, so for optimum viewing one should try and get into the
countryside.
Can you listen to the Northern Lights?
Throughout the ages there have been numerous
reports of people actually hearing the aurora. So far, attempts to record
any such sounds have failed and most scientists are skeptical.
Mythology and folklore about the Northern Lights
From ancient times the Aurora Borealis has
intrigued mankind and the phenomenon features prominently in the mythology
and folklore of those living in northerly latitudes. The Northern Lights
have been described and imaginatively explained by the Inuit peoples of
Canada and Greenland, various Native American tribes, world explorers and
they are even mentioned in the Old Testament. Such men as Aristotle,
Descartes, Edmund Halley and Goethe were fascinated by this night-sky
phenomenon and wrote papers on it.
In Iceland it was believed that if a pregnant woman gazed the northern
lights then her child would be cross eyed.
To look skywards on a crisp, clear night and see these giant curtains of
light weaving and swaying, gliding and flowing gracefully across the
northerly heavens is pure magic. The Norwegian poet, Knut Hamsun, in his
poem Snow, aptly likened the aurora to a "heavenly feast".
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