A
fter finally witnessing a total solar
eclipse and declaring it the most
beautiful thing I’ve ever seen, I
started hearing people say things like,
“Wait until you see the northern lights.”
So when fellow pro photographer Don
Smith and I planned an Iceland photo trip
to prepare for our upcoming photo work-
shop, we chose January because it’s in the
heart of northern lights season. Could the
beauty of the northern lights really rival
a total solar eclipse? (Spoiler alert: Yes.)It Only Looks Like Magic
The sun continuously bombards Earth with
a “solar wind” of electromagnetic wavesand particles. Each wavelength and parti-
cle in the broad spectrum of solar energy
interacts differently with the atmospheric
atoms and molecules it encounters. Some
wavelengths bounce harmlessly back out
to space; the narrow range of infrared and
visible energy warms our days, colors our
sky and lights our way; the ultraviolet
wavelengths burn our skin; and the most
energetic solar energy alters the atoms and
molecules that cause an aurora.
The solar wind’s electromagnetic par-
ticles and its highest frequencies contain
enough energy to strip electrons from
atmospheric atoms and molecules, creat-
ing a charge imbalance called ionization.The majority of this super-charged ioniz-
ing radiation is emitted by coronal mass
ejections, solar storms that send ener-
gized particles hurtling toward Earth.
Instead of penetrating our atmosphere
to create havoc below, most of the sun’s
ionizing radiation is deflected by the mag-
netosphere, Earth’s protective magnetic
shield. Constant bombardment from the
solar wind makes the magnetosphere tear-
drop-shaped. The battered side facing the
sun is compressed and spread horizon-
tally, while the shielded side stretches like
a tail behind Earth, thinning with distance.
As Earth rotates, our daylight side is
always behind the magnetosphere’s thin
but densely compressed region, while the
night side looks out through the magne-
tosphere’s more diffuse extended region.
Just as the upwind side of a wall or build-
ing shelters whatever is directly behind
it, the sunward side of the magnetosphere
channels ionized particles to the upper
regions of Earth’s leeward (night) side.
These atmospheric machinations
spread an oval of aurora-causing geo-
magnetic activity high in the atmosphere,
always on Earth’s night side. The size
and intensity of this ovular aurora region
vary daily (and, on a smaller scale, by
the hour or minute), corresponding to
the intensity of the solar energy reach-
ing Earth. The larger it is, the lower the
latitude an aurora will be visible.
Green is the dominant aurora color,
but the color can vary with the atoms and
molecules involved and their altitude.
Oxygen creates a green and sometimes
yellow aurora, while nitrogen produces
red, violet and blue. Greens appear at
elevations below 150 miles; above that,
red dominates. Blue only appears in the
lowest altitudes.Aurora Prediction
As with any terrestrial weather event,
there’s no such thing as an aurora “sure
thing”—the best we can do is put our-
selves in position to be as close as pos-
sible to the auroral oval on nights with
the greatest chance for auroral activity.
Winter is best because the nights are both
longer and darker, so planning a winter
trip to the high latitudes (the higher, the
better), like Iceland, is a great start.
Sony a7S II, Sony FE 24mm F1.4 GM. Just as important as getting to an area
Exposure: 5 sec., ƒ/1.4, ISO 12800