Solar physicists have been waiting for the appearance of a
reversed-polarity sunspot to signal the start of the next solar cycle. The wait
is over.
A magnetically reversed, high-latitude sunspot emerged.
I can very well remember that night in March 13, 1989.
MrWabbit had decided to go out into the shed to bring some wood for the fire
into the house, I had retired for the night and was already in bed watching
ironically a science documentary on searching for the possibility of life on
some other planet somewhere in our Universe with scientists sending recorded
messages out into space also digital signalled radio waves with the hope to get
some response back even if thousands of years may elapse.
Suddenly the television began to act up funny as if someone
was turning down the electrical current to an incredible low. I got up to look
for MrWabbit thinking what did he get into now with his experiments, by this
time as I walked from one room into the other all the lights were also dimming
and I had this sort of smirking but uneasy feeling of what kind of joke is he
playing to make everything so spooky? Or is this real and maybe the entire
house will explode for sure this time.
As the house ever so slowly dimmed more and more the
brighter the outside appeared that night, until I actually went outside to tell
MrWabbit to stop fooling around and realized the entire sky was lit up a bright
pink and orange hue making the snow also appear a neon pink alternating into a
neon orange.
We stood watching the skies, looking at each other and I
know his mind was racing as fast as mine.
Solar flares, known as coronal mass ejections, carry with
them many protons and electrons which reach the Earth's magnetosphere, where it
produces quite an auroral show.
The danger
But these solar flares also send out clouds of charged
particles that could damage communication systems and power grids. Astronauts
also need to be aware of when a CME will occur not to be outside on a space
walk at that time since the radiation will do critical damages.
A solar storm on March 13, 1989 jolted Hydro Quebec and left
six million people without power for up to nine hours. Airliners on routes over
the Arctic had to be diverted south, since the Earth's magnetic field offers
less protection near the poles.
The storm is also a threat to satellites.
If you bombard any electric equipment with protons and
electrons travelling 1,000 kilometres a second, it can affect the computer
systems and it could take some of them out.
An important, unknown component to the storm is its magnetic
orientation. If it lines up a certain way with the Earth's magnetic field, the
storm could pour into the Earth's upper atmosphere and do some electrical
damage. If it aligns otherwise it could simply pass by the planet with few
consequences.
To understand our Sun
The Sun is the most prominent feature in our solar system.
Approximately 150 million kilometres from us it is the largest object and
contains approximately 98% of the total solar system mass. One hundred and nine
Earths would be required to fit across the Sun's disk, and its interior could
hold over 1.3 million Earths. The Sun's outer visible layer is called the
photosphere and has a temperature of 6,000°C (11,000°F). This layer has a
mottled appearance due to the turbulent eruptions of energy at the surface.
Solar energy is created deep within the core of the Sun. It
is here that the temperature (15,000,000° C; 27,000,000° F) and pressure (340
billion times Earth's air pressure at sea level) is so intense that nuclear reactions
take place.
As amazing as it sounds our sun is really a very ordinary
one. The Sun appears to have been active for 4.6 billion years and has enough
fuel to go on for another five billion years or so. At the end of its life, the
Sun will start to fuse helium into heavier elements and begin to swell up,
ultimately growing so large that it will swallow the Earth. After a billion
years as a red giant, it will suddenly collapse into a white dwarf -- the final
end product of a star like ours. It may take a trillion years to cool off
completely. In comparison to other stars (suns) that are 3 times more massive
than ours, but very unstable with its core cooling quickly and ending up as a
super nova.
The corona is the outer part of the Sun's atmosphere. It is
in this region that prominences appears. Prominences are immense clouds of
glowing gas that erupt from the upper chromosphere. The outer region of the
corona stretches far into space and consists of particles traveling slowly away
from the Sun. The corona can only be seen during total solar eclipses.
To Understand Magnetic Loops in the Sun's Corona
Magnetic fields can be thought of as lines that connect
north and south polarities. On the Earth these lines run from north to south
and are uniform and organized. This is why we can navigate so well with a
magnetic compass.
Another important property of magnetic fields is that they
trap and contain hot gases. They are, in effect, "magnetic bottles".
On earth, laboratory experiments to produce energy from controlled fusion
depend on this property of magnetic fields to contain the super-hot gases.
On the sun, the magnetic fields connect opposite polarities
just as on the Earth. However, while the Earth only has one north and one south
pole, on the Sun we observe bits of north and south polarity scattered all over
the surface. Furthermore, their position and strengths are constantly changing.
The magnetic fields connecting these poles loop out into the corona in a
bewildering array of shapes and sizes. They are visible in X-rays because of
the hot gas that they trap.
When some of the Sun's magnetic field lines are filled with
hot gas, we see a magnetic loop:
So if on any given night your lights behave suspiciously,
your dish lost reception to your favourite movie, and your cell phone goes
dead, no it’s not the end of the world, it’s a powerful coronal mass ejection
(CME) giving us the biggest aurora show of all.
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