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Like a doctor listening to a heartbeat, solar scientists are
listening to the Sun to answer some of its great
mysteries. Known as helioseismologists, they
are using instruments like the Michelson Doppler Imager (MDI)
aboard NASA's Solar and
Heliospheric Observatory (SOHO) spacecraft to learn more about
our noisy neighbor.
While German philosophers
likened an understanding of the Sun's inner-workings to a
theoretical impossibility, today's helioseismologists are making
discoveries like the following:
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Rivers of plasma transport material
beneath the solar surface, much like Earthly trade winds.
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Solar 'weather' patterns are driven by
heat rising from the solar core and by the
twisting/contorting of magnetic fields interacting with
the electrically-charged plasma.
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Different points on the Sun rotate at
different speeds (ranging from 27-35 days for a complete
rotation) with the equator rotating at the fastest speeds
and poles the slowest.
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Likewise, levels in the Sun vary in
temperature, having often proven cooler or hotter than
expected.
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Helioseismology
has allowed scientists to view the far side of the Sun,
allowing for more advanced warnings of dangerous solar
activity.
Remaining
mysteries for helioseismology include:
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What
is the significance of the Sun's 11-year cycle? Is
it driven by the solar interior's pulsing gas?
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Do activities within the Sun influence
activity on the surface?
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What heats the Sun's million-degree
corona?
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What accelerates the Sun's solar wind?
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