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| The canyon-like hole, visible as a dark gulf running vertically down the sun's center. (Image credit: NOAA Space Weather Prediction Service) |
A "canyon-like" hole in the sun's atmosphere has opened up and may launch a
high-speed stream of solar wind into Earth's magnetic field from Thursday
(Dec. 1) to Friday (Dec. 2), and will possibly cause a minor geomagnetic
storm,
according
to spaceweather.com.
The coronal hole is a gigantic solar gulf stretching across the sun’s
center. Coronal holes are areas in the sun's upper atmosphere where our
star's electrified gas (or plasma) is less hot and dense than in other
regions, which makes them appear black in contrast. Around these holes,the
sun's magnetic field lines, instead of looping back in on themselves, point
outward into space, beaming solar material outwards at up to 1.8 million mph
(2.9 million km/h),
according
to the Exploratorium, a science museum in San Francisco.
This barrage of energetic solar debris, mostly consisting of electrons,
protons and alpha particles, is absorbed by Earth’s magnetic field, which
becomes compressed, triggering a geomagnetic storm. The solar particles zip
through the atmosphere near the poles where Earth's protective magnetosphere
is weakest and agitate oxygen and nitrogen molecules — causing them to
release energy in the form of light to form colorful auroras such as the
northern lights.
The storm that could hit Earth on Thursday will likely be fairly weak.
Predicted to be a G-1 geomagnetic storm, it could cause minor fluctuations
in power grids and impair some satellite functions — including those for
mobile devices and GPS systems. It could also cause an aurora to appear as
far south as
Michigan and Maine.
More extreme geomagnetic storms, however, can have far more serious effects.
They can not only warp our planet's magnetic field powerfully enough to send
satellites tumbling to Earth, but can disrupt electrical systems and even
cripple the internet.
Geomagnetic storms can also come from two other forms of solar activity:
coronal mass ejections (CMEs) or solar flares. Debris that erupts from the
sun in the form of CMEs usually takes around 15 to 18 hours to reach Earth,
according to the
Space Weather Prediction Center. The bright flashes of solar flares, which can cause radio blackouts,
travel at the speed of light to arrive at Earth in just 8 minutes.
The upcoming storm is just the latest in a string of solar barrages fired at
Earth as the sun ramps up into the most active phase of its roughly 11-year
solar cycle.
Astronomers have known since 1775 that solar activity rises and falls in
cycles, but recently, the sun has been more active than expected, with
nearly double the sunspot appearances predicted by the
National Oceanic and Atmospheric Administration. Scientists anticipate that the sun's activity will steadily climb for the
next few years, reaching an overall maximum in 2025 before decreasing again.
The largest solar storm in recent history was the 1859 Carrington Event,
which released roughly the same energy as 10 billion 1-megaton atomic bombs.
After slamming into Earth, the powerful stream of solar particles fried
telegraph systems around the world and caused auroras brighter than the
light of the full moon to appear as far south as the Caribbean. It also
released a billion-ton plume of gas and caused a blackout across the entire
Canadian province of Quebec,
NASA reported. If a similar event were to happen today, scientists warn it would cause
trillions of dollars’ worth of damage and trigger widespread blackouts, much
like the 1989 solar storm that released a billion-ton plume of gas and
caused a blackout across the entire Canadian province of Quebec,
NASA reported.
But this may not even scratch the surface of what our star is capable of
hurling at us. Scientists are also investigating the cause of a series of
sudden and colossal spikes in radiation levels recorded in ancient tree
rings across Earth's history. A leading theory is that the spikes could have
come from solar storms 80 times more powerful than the Carrington Event, but
scientists have yet to rule out some other potentially unknown cosmic
source.
Source: Link
Tags:
Space & Astrophysics