BRN 9-2 (uncompressed) - Flipbook - Page 97
Aurora Borealis
Is it weather if it happens in the upper
parts of the atmosphere? If so, the
big weather event of 2025 occurred
in November when there was a very
strong coronal mass ejection (CME)
from our star. These blasts of intense
radiation are often associated with
sunspots on the solar surface (corona).
These radiation events can travel
through space at about 1,900 miles
per second but their speed is variable.
The slowest CMEs travel through
space at a leisurely 155 miles per
second or so. Once a CME occurs, the
radiation event may reach earth in as
little as 15 hours, or it may take
several days. The radiation from a
solar ßare, on the other hand, travels
at the speed of light and reaches the
earth in about 8 minutes.
CMEs occur when the sunÕs magnetic
Þeld trips all over itself, creating very
strong localized magnetic Þelds
which can erupt through the surface.
When this effect of the sunÕs magnetic
Þeld reaches the earth it disrupts our
own magnetic Þeld, intensifying the
geomagnetic storms which normally
occur here. Radiation from the sun
most easily penetrates the EarthÕs
magnetic Þeld at the magnetic poles.
That is why the auroras, which are the
ÒvisualÓ manifestations of the EarthÕs
geomagnetic storms, are common in
the arctic and antarctic regions of the
planet. In the north, the aurora is
known as the aurora borealis, or more
commonly as the northern lights.
Although the aurora borealis has been
seen as far south as El Salvador,
Hawaii, and Cuba in the Western
Hemisphere (the Carrington Event of
1859) and perhaps farther south
during periods unrecorded by
humans, it is generally seen only in
the very northern part of North
America (including southern Canada
and the very northern part of the
United States) in the Western
Hemisphere.
The geomagnetic storm of November
2025 was quite intense (a G-4 class
storm) with solar radiation
penetrating more deeply into the
atmosphere than is usually the case.
Because of this the aurora borealis
was seen in North America as far
south as the northern states of
Mexico.
At around 8 p.m. on November 11
John West, Therese Van Buskirk, and
Debora Nicoll took the photos of the
northern lights shown at the right.
JohnÕs photograph is the Þrst in the
series, followed by one of ThereseÕs,
and lastly a photograph of the aurora
behind Berrenda Mountain by
Debora. Additional photographs
were included in the Natural
History Blog post about the event
on November 12, 2025.
Differences in color in the photos
are a function of the cameras
used and their settings.
The composite image above, from
NOAA, was taken by the Joint
Polar Satellite System (JPSS) on
November 11-12. This image of
the aurora borealis, as seen from
space, is interesting from a
number of perspectives: It
shows the arrangement of the
EarthÕs magnetic Þeld (what we
are seeing is the geomagnetic
storm as it is conÞned by the
planetÕs magnetic Þeld); it shows
how far south the geomagnetic
storm occurred and hints at its
intensity (note how bright it is);
and given how far south the
aurora was seen, it shows how
high in the atmosphere these
events occur.
The science of auroras is covered
well in NOAAÕs (and speciÞcally
the Space Weather Prediction
CenterÕs) Aurora Tutorial.
The November event is not likely
to be replicated anytime soon,
but your chance of seeing such an
event in the future is greatly
enhanced if you follow the Aurora
Dashboard. This NOAA site
forecasts auroras.
We see the beauty of the aurora,
but the geomagnetic storms that
they highlight are very dangerous
in a technologically driven world.
They have the capability of
seriously disrupting all sorts of
electrical and electronic systems.
Thus the need to predict their
occurrence.
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