|
| Aurora
Facts |
|
Where Seen |
Mainly Polar
latitudes |
|
When seen |
Clear cold nights |
|
Average Duration |
Several hours |
|
Avg. Height
|
50 to 100 miles
up |
|
Common colors |
Pale green and
pink |
|
Inuit Auroral
Myth |
Guiding torches
for departing spirits |
|
Most common
shape |
Spiral
curtains, arcs, or streamers |
| Free
E-Newsletter |
| Receive
Arctic News, Weather and Travel Information
Click
Here! |
|
|
|
The Northern Lights are caused
by plasma particles from the sun (part of the
solar wind) which enter the atmosphere.
Collisions between the electrically
charged particles and Earth's magnetic field ionize
oxygen and nitrogen atoms, releasing light.
The lines of force of the
Earth's magnetic field draw the solar particles
toward the polar regions.
Blue and purplish-red light
comes from ionized nitrogen molecules, green from
oxygen molecules.
During periods of high activity,
a single auroral storm can produce one trillion
watts of electricity with a current of one million
amps. |
|
The
Aurora Borealis
(Northern Lights)
The Aurora Borealis or Northern Lights are mesmerizing,
dynamic displays of light that appear in the nighttime Arctic
skies. They are, in effect, nature's light show; visual poetry
penned from the quantum leaps of atmospheric gases. As those
who have witnessed the Aurora can attest, few sights can equal
the magic and mystery of these luminous sheets of color undulating
in the frigid air of an Arctic night.
Although auroras appear in many forms -- pillars,
streaks, wisps and haloes of vibrating color -- they're most
memorable when they take the form of pale curtains which seem
to float on a breeze of light. Known as 'Aurora australis'
in the south, auroras occur in the upper atmosphere of both
poles and are occasionally visible from middle latitudes as
a dark red glow near the poleward horizon. They are most commonly
seen at midnight hours in the north in a circle including
southern Hudson Bay, southernmost Greenland, Iceland, the
northern tip of the Scandinavian peninsula, the Arctic coast
of Siberia, and central Alaska.
The amazing color displays and formations are
produced by the solar wind -- a stream of electrons and protons
coming from the sun -- as it collides with gases in the upper
atmosphere. These collisions produce electrical discharges
which energize atoms of oxygen and nitrogen causing the release
of various colors of light. Earth's magnetic field channels
these discharges toward the poles. Variations in sunspot activity
or the occurrence of so-called 'coronal holes' can often considerably
enhance the auroral discharge adding to the intensity and
duration of the displays.
Auroral displays appear in many colors with
pale green and pink the most common. However, different shades
of red, yellow, green, blue, and violet have all been observed.
Green results from energized oxygen atoms and pink from nitrogen
molecules. The color variations are a product of the altitude
of the storm, and the density and composition of the ions
at that altitude. The folding effect results from the electric
field induced on either side of the auroral curtain by the
electrons.
Inidigenous peoples have many different myths
to explain the Aurora Borealis. The Inuit, for example, attach
spiritual significance to the lights, believing them to represent
the souls of their unborn children or the torches of long-departed
ancestors. In Middle-Age Europe, the northern lights were
thought to be reflections of slain warriors battling valiantly
in the heavenly skies for eternity.
|