Electrons carried along with the solar wind strike
atoms of nitrogen and oxygen. Atomic oxygen creates the green aurora; nitrogen
emits pink-red, blue, and purple auroras, while the rare bright red and orange-red
Auroras are produced from higher altitude atomic oxygen.
What
creates the shapes of the Aurora? The energy output of the solar wind
traveling along the earth's magnetic field creates the patterns of the Auroras
we see. These include homogenous arcs, bands, active arcs, rays, pillars, draperies,
or curtains and coronas.
Where
can Auroras be viewed? Auroras exist constantly as oval shapes over both
of the polar regions of our earth as well as other planets in our Solar system.
The Aurora Borealis, or 'Northern Lights, is viewed far more frequently than
the Aurora Australis, the 'Southern Lights' because there are huge landmasses
in our northern hemisphere and mostly water around Antarctica. The Auroral ovals
are basically 'born' around the Arctic and Antarctic Circles. As the aurora
becomes more energetic, the ovals expand and can be seen in the night skies closer to areas above and below the equator.
(See the NOAA website linked on the 'HOME" page.)
Aren't
Auroras better the colder it gets? No! The temperature on earth has
absolutely nothing to do with auroral activity or formation. From
below the edge of
space and beyond it is below freezing all the time.
Can
Auroras be seen during Alaska's summers? No! To view the Aurora one needs
darkness-night-twilight. Alaskan summers do not allow a view into the heavens
because the atmosphere is too brightly lighted by the sun. Southern Canada and the
northern tier of the United States are able to see the Auroras because there still exists
a darker 'nighttime'. August through April is the best time period to view Auroras in Alaska.
How
do Auroras affect our Earth? Auroras are called 'geomagnetic storms'.
Powerful storms can cause great havoc by creating immense electrical
surges on power grids, transmission lines, navigation systems, radio communications,
and at satellite altitudes. Space Shuttle Astronauts must seek protection inside the shuttle itself when auroras are present
due to high levels of radiation in space.
Do
Auroras ever touch the ground? No! While numerous people say they've 'seen the
Aurora
touch the ground, it has never been scientifically proven to be able to occur
that low. The 'recipe' for Auroral formation cannot exist below a certain height,
usually just below 60 miles above our heads. Auroras normally extend from 60
miles at the lower border to approximately 200 miles high.
Very powerful Auroras have been measured as high as 600 miles. It is
an optical illusion that auroras touch the ground because this massive phenomenon
bends and vanishes over the curvature of the earth and appears to lower as we
lose sight of it.
Can
Auroras be predicted? Sometimes! Consider the 'success rate' of your local weatherperson.
When trying to predict Auroras, the degree of difficulty increases a thousand
fold. Science and technology are bringing us closer to the day when predictions
will be far more accurate. (Again, see the linked NOAA presentation on the
"HOME" page.)
What
does it take to photograph the Aurora? Mostly it takes the 'patience of
a glacier', along with cold fingers and toes. If you have a good 35mm
camera (NOT a 'point & shoot'), a cable release, and a tripod you're
almost ready to go. Pick out a variety of midrange to higher ASA
films you enjoy working with, and pick out a nice dark location. Play around
with your exposures of up to a minute long because the aurora evolves in just
seconds. The real true key to successful auroral photography: Be There!
However, I MUST EMPHASIZE STRONGLY that
your SAFETY COMES FIRST! No photograph of
the Aurora is worth getting frostbitten body parts. STAY
WARM!
