Traveling at the near speed of light, energetic
particles shooting out from the sun can zip
through space, smack into our planet’s atmosphere,
and cause incredible disruptions. And one
of the biggest impacts we know of happened
during the tail end of the Vietnam War. President
Nixon really wanted to pull us out, but wanted
to do it sort of saving face, and decided
that the best way to do that was to stop the
flow of war material into North Vietnam. The
decision was to mine Haiphong Harbor, and
many of the smaller harbors to the South.
This is Delores Knipp, a space weather scientist
and former officer in the US Air Force. She
likes digging into dusty archives, and uncovered
a war mystery that’s now connected to a
major solar event. Space weather forecasters
had noticed that there was one region on the
Sun that appeared to be a little more active
than anticipated. They kept watching it, and
then when it came around in late July 1972
on the east limb of the Sun it was already
large. It did start producing solar flares,
producing coronal mass ejections but at that
time we didn't have those words. We didn't
really understand the concept of the Sun actually
throwing mass, and magnetic material out.
We had a general sense that something like
a plasma cloud was coming at us, but our ideas
were that, "Well, okay it might get here in
a couple three days." As a matter of fact,
it got here in 14.6 hours. Typically, the
solar wind is moving at about 400 kilometers
per second, which is supersonic, but very,
very tenuous. But this particular event in
1972 traveled at about 2,800 kilometers per
second, so seven times faster than the norm,
and carrying tremendous magnetic field, and
mass with it. And when that hit, our magnetic
shield virtually buckled. We had no idea that
something could come from the Sun that fast.
We were pretty much unprepared. And when it
hit earth, those sea mines blew up. Those
mines were what the president was relying
on to keep the pressure on in the war. And
suddenly the whole mine field had been swept
by nature, by the Sun, by a CME. That created
probably one of the largest solar energetic
particle events in recorded history. The naval
observers who were up at the time, it was
just past dawn, noted that there were a half-dozen
sea mines that blew within 30 seconds. And
they go, "Whoa! Did we do that?" It was a
furious time in terms of the Navy records,
trying to figure out what had happened. In
these declassified reports, Delores found
just a few lines that had basically said,
"Yes, in August of 1972 "a solar storm swept
the sea mines in Haiphong Harbor." And so
I go, "Oh, it looks like something did happen." There
were and are many impacts that have not been
adequately described. And they're just now
starting to come to light. Our sun is a huge
ball of magnetized gas and plasma, and it’s
activity goes through a roughly 11 year cycle. We
know whether we’re in a solar maximum or
solar minimum by counting the number of sunspots
on the surface. These spots are indicators
for giant eruptions, like solar flares, which
are sudden outbursts of energy and coronal
mass ejections, which are even larger but
slower eruptions from the Sun’s corona. They
can increase during the sun’s cycle, but
luckily, we have some built in protection.
We can think of Earth's magnetic field as
being kind of a magnetic cocoon that keeps
most of the solar winds, magnetic field, and
the plasma outside of Earth's atmosphere.
But when the sun decides to launch a really
big ejection, sometimes the magnetic field
has to deform so dramatically that currents
are generated, and those currents can actually
flow along the magnetic field lines down to
Earth's surface. And that's one of our biggest
concerns. If those extra currents are flowing
in the ground, they're always looking for
the path of least resistance. And when they
find a path along a long conducting pipe,
or in older times, telegraph wires, or now
in our power grid, they will take that path. We're
starting to understand that these are not
once in a century events. These probably occur
more often than we think. We're in solar
minimum now, we're kind of relaxed the next
solar maximum was forecast to be not too spectacular. The
August '72 event came out of small sunspot
cycles. So we can't just take the sunspot
count as the, oh, we don't have to worry about
it situation. We actually have to be monitoring
the Sun 24/7. Today at NOAA’s Space Weather
Prediction Center, we have more eyes on the
sun and better models to help us predict space
weather, which is affecting our magnetosphere,
it's creating the Aurora, it's also energizing
particles and creating radiation environment
that can affect satellites, it affects the
ionosphere in those regions and that impacts
airlines that have flights from New York to
Beijing. There are several things that are
really important for conducting space weather
operations. The first are satellites, which
serve as sentinels out in the abyss. The
GOES satellites give you the daily weather
that you see on the news at night. But in
addition, the space weather observations
consist of monitoring the energetic particles
in Earth's radiation belt at geosynchronous
orbit. They also monitor the earth's magnetic
field and its variations. There's solar observations
that are looking at the Sun in x-rays, in
extreme ultraviolet to give us information
about activity on the sun. Activity like coronal
mass ejections and solar flares, which have
different lead times once they erupt. We
classify solar flares here starting with what
we call A. And then we have the B level and
then C level and then M’s and then X’s.
And each one of those categories is ten times
more intense than the other. The 1972 event
that blew up a bunch of sea mines were connected
to X class flares. We have instruments measuring
the intensity of the solar radiation and it
appears very quickly in near real time in
front of our forecasters and then they could
use that information to provide their warnings
and alerts. The other type of major event
is this coronal mass ejection, it’s moving
much slower. Right now we're using coronagraphs
that are on a NASA satellite. It takes as
short as maybe 14 hours for a very fast event…but
it can take more normally several days to
reach us. We have a little bit more lead
time..to say something about how fast is it
moving? When do we expect it at Earth? How
long do we expect it to last?" We've got another
satellite that's entirely outside of earth's
magnetosphere in a location between Earth
and the Sun called the Lagrange point L1.
That's a stable place where both the gravity
and the centrifugal force of the satellite
balance out the earth's gravitational force
and it's always there as a buoy upstream to
give us a warning of what's coming at Earth. Another
key piece of their operations are models,
which are constantly evolving to improve predictions. The
Wang Sheeley Arge Enlil model shows us where
there's high speed solar wind coming at us,
where there's low speed solar wind coming
at us, the density of that solar wind. When
there's a large eruption on the sun of a coronal
mass ejection. The Wang Sheeley Arge Enlil
model.. takes that coronal mass ejection and
puts it through that system and then it tells
us what's going to arrive at Earth. The Geospace
model is telling us about magnetic variations
in the vicinity of Earth and those magnetic
variations can cause geo electric fields.
Those geo electric fields can drive currents
and power lines and disrupt power grids. Models
are only as good as our understanding and
models don't catch everything and there are
times where we have been surprised. There
are a lot of features about the sun that we
still don't understand. We need to be able
to model how the Sun's interior works the
solar atmosphere. We need to be able to monitor
active regions of the sun and how they form. There
is a huge concerns at the highest levels in
government to be able to better prepare for
a large event to better mitigate the effects. I'm
optimistic about all of these new advances
that are coming in and all of these things
which are going to contribute to our preparedness
for the things the Sun is throwing at us.
It's a real sense of adventure. It's like
you can realize that you're a part of something
that is developing. The Sun, it's so far away
and yet, within a short amount of time, it
can have this amazing impact. And it's not
just oh yeah, the sun warms us up and we have
seasons, there's a lot more going on, and
it's a very connected system. Even though
some of these stories have been hidden these
things have actually happened, and there's
a potential for it to happen again.
