Once every 11 years, something unusual happens on the sun:
The sun’s polar magnetic field weakens, bottoming out at nothing. the magnetic
field appears again, it will be reversed. The sun’s north pole will go from
negative to positive, and the south pole will switch from positive to negative.
During the height of the solar cycle, the magnetic field
changes polarity, pushing a ripple effect across the Solar System that's
detectable by even the far-away Voyager probes.
Data from NASA-supported observatories indicate that the
next flip will happen in just three to four months – the north pole has already
jumped the gun and reversed, and scientists are not just waiting for the south
pole to catch-up. The completed flip will herald changes throughout the entire
solar system, according to a NASA video.
The sun’s magnetic influence extends some 8 billion miles
through a region called the heliosphere. That region ends at the heliopause,
the outermost boundary of our solar system that abuts interstellar space. So,
when the sun’s polarity flips, the entire solar system will fell the effects of
the change.
During the flip, what is known as the sun’s sheet – a
massive surface some 10,000 km thick and billions of miles wide extending
outward from the sun's equator – will become wavy. That wavy sheet will create
cosmic “stormy weather” throughout the solar system. At the same time, it will
also better deflect the cosmic rays spewed from distant supernovae than does a
smooth sheet, protecting shuttles and astronauts from the particles.
The sun's magnetic field flips at the peak of each solar
cycle, each of which are about 11 years long. This coming reversal will mark
the midpoint of Solar Cycle 24, a solar maximum.
Solar maximums and minimums provide important data to
scientists looking to create a better portrait of the still mysterious outer
bounds of the solar system: Each change in the sun’s cycle provides an
opportunity to assess how the sun’s particles from a minimum or a maximum
behave in the altered solar system, and then extrapolate what the solar
system’s outer boundaries looks like.
Last month, IBEX, NASA’s Interstellar Boundary Explorer in
orbit around Earth, used data recorded from the sun’s particles spewed off
during its solar minimum to prove that the solar system has a tail. At the
time, scientists said that they were still awaiting data from particles
released from the sun during its solar maximum, since those particles had not
yet had enough time to ricochet toward the heliopause and then rebound back to
IBEX.
Scientists have been monitoring the sun’s polarity since
1976, and have recorded three flips, with the fourth due this fall.
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