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What comes to mind when you think of Halloween? Trick-or-treating,
jack-o’-lanterns, ghouls and goblins?
(Screeching)  But the sun? Probably not.
But, just five years ago, in the weeks surrounding Halloween,
the sun sent us some tricks and treats of
its own.  The tricks were a series of some of
the most powerful solar storms ever measured,
storms that disrupted power grids, communication lines and satellites.
But the treats were some extraordinary
auroras, seen as far south as Florida and Texas.
Holly Gilbert:  The effects of these storms on
the Earth were ghoulish enough that we had to
re-route aircraft, it affected satellite
systems and communications, and it also caused a power
outage in Sweden for about an hour.
Generally the public was very excited to see the
ghostly aurora that were ignited in the night sky.
The aurora are normally limited to the higher latitudes,
so these storms were so powerful they created aurora
that could be seen as far south as Florida. So you can imagine
seeing the ghostly figures haunting the night sky.
In all, nearly 17 major
flares erupted on the Sun during those two weeks in
2003, the result of energy building
up in the Sun's magnetic field lines until they became
strained enough to suddenly snap like an overstretched rubber
band. The results were coronal mass
ejections, the largest explosions in the solar system,
able to launch up to 10 billion tons of electrified
gas into space, and cause some of the ghoulish
effects we felt here on Earth.
These storms were also eerie because they came at such a surprising time.
Gilbert: These storms were spooky because of the timing of which they occurred.
That is to say that it did not occur in a stage where most of the activity occurs.
In fact it occurred about 3 and a half years after solar maximum occurred, so it was
spooky in that respect. And it was also spooky in the intensity
of the storms. These were some of the largest storms ever observed.
So can we expect to see any ghostly-looking auroras in this night sky
this Halloween?    Gilbert:  I don’t thing we’re going to see a repeat this Halloween
on the 5 year anniversary because we’re at a time when there are very little active regions
on the sun. However, we're going to be ascending to greater period
of solar activity. We may see some large storms in the next
few years.  Still think the Sun isn’t so scary?
Hopefully this spooky tale will make you think again.
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