Breaking News: There's a Hole in the Sun, NASA Says
Δημοσιεύθηκε στις 4 Ιουν 2013
During the latter part of last week, a huge void rotated across the face of the sun.
But
never fear, it isn't a sign of the "end times" or some weird sci-fi
stellar malnourishment: This particular hole is a coronal hole. Though
it may be a well-known phenomenon, it is noteworthy — it's the largest
coronal hole to be observed in the sun's atmosphere for over a year.
Snapped
through three of NASA Solar Dynamics Observatory's (SDO) extreme
ultraviolet filters, this coronal hole is caused by a low density region
of hot plasma.
The sun's lower corona is threaded with powerful
magnetic fields. Some are looped — or "closed" — very low in the corona,
creating the beautiful, bright coronal loops that trap superheated
gases that generate vast amounts of extreme ultraviolet light, radiation
that is produced by multimillion degree plasma
However, there are
also "open" field lines that have one end of their magnetic flux
anchored in the solar photosphere. These lines fire solar plasma into
interplanetary space at an accelerated rate, often intensifying space
weather conditions. These regions of open field lines, or coronal holes,
act like fire hoses, blasting plasma into space. These regions are the
source of the the fast solar wind that accelerates solar material toward
Earth, which often only takes 2-3 days to travel from the sun to Earth.
Through
the SDO's eyes, coronal holes appear dark as there is a very low
density of the multimillion degree plasma generating the EUV radiation.
And as this dramatic observation demonstrates, to the eyes of the SDO,
the sun really does appear to have a hole.
We are currently going
through an uptick in solar activity as our nearest star experiences
"solar maximum" — the peak of its natural 11-year cycle. At this time,
we can expect an increased frequency of solar flares and coronal mass
ejections as the sun's magnetic field becomes increasingly stressed.
Although this solar maximum is less active than predicted, it is
producing some powerful flares and CME's.
Now we're seeing huge coronal holes, all a consequence of the twisted turmoil our sun is currently enduring.
But
never fear, it isn't a sign of the "end times" or some weird sci-fi
stellar malnourishment: This particular hole is a coronal hole. Though
it may be a well-known phenomenon, it is noteworthy — it's the largest
coronal hole to be observed in the sun's atmosphere for over a year.
Snapped
through three of NASA Solar Dynamics Observatory's (SDO) extreme
ultraviolet filters, this coronal hole is caused by a low density region
of hot plasma.
The sun's lower corona is threaded with powerful
magnetic fields. Some are looped — or "closed" — very low in the corona,
creating the beautiful, bright coronal loops that trap superheated
gases that generate vast amounts of extreme ultraviolet light, radiation
that is produced by multimillion degree plasma
However, there are
also "open" field lines that have one end of their magnetic flux
anchored in the solar photosphere. These lines fire solar plasma into
interplanetary space at an accelerated rate, often intensifying space
weather conditions. These regions of open field lines, or coronal holes,
act like fire hoses, blasting plasma into space. These regions are the
source of the the fast solar wind that accelerates solar material toward
Earth, which often only takes 2-3 days to travel from the sun to Earth.
Through
the SDO's eyes, coronal holes appear dark as there is a very low
density of the multimillion degree plasma generating the EUV radiation.
And as this dramatic observation demonstrates, to the eyes of the SDO,
the sun really does appear to have a hole.
We are currently going
through an uptick in solar activity as our nearest star experiences
"solar maximum" — the peak of its natural 11-year cycle. At this time,
we can expect an increased frequency of solar flares and coronal mass
ejections as the sun's magnetic field becomes increasingly stressed.
Although this solar maximum is less active than predicted, it is
producing some powerful flares and CME's.
Now we're seeing huge coronal holes, all a consequence of the twisted turmoil our sun is currently enduring.
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