The sun's next cycle of increased
activity might have begun last week, according to a NASA scientist.
Solar activity waxes and wanes on an
11-year cycle. During the peak, the last of which occurred in 2001 and 2002,
sunspots are common and solar storms
frequent. The storms, which pummel Earth with charged particles, can knock out
satellites and occasionally disrupt radio and even power transmissions on the
planet.
The sun has been relatively quiet
for many months. Now, a modest knot of magnetism, which appeared Dec. 11, might
signal the long upward trend in activity.
"This
patch of magnetism could be a sign of the next solar cycle," said solar
physicist David Hathaway of the Marshall Space Flight Center. "Solar
minimum is upon us."
The shift would mark the beginning
of Solar Cycle 24.
Uncertain beginnings
"New
solar cycles always begin with a high-latitude, reversed polarity
sunspot," Hathaway explained in a NASA statement.
"Reversed
polarity" means a sunspot with opposite magnetic polarity compared to
sunspots from the previous solar cycle. "High-latitude" refers to the
sun's grid of latitude and longitude. Old cycle spots congregate near the sun's
equator. New cycle spots appear higher, around 25 or 30 degrees latitude.
The shift
is not certain, however. If it's really the start of a new cycle, there ought
to be a sunspot associated with the magnetic knot, but there is none. In fact,
Hathaway announced a similar
possible beginning to Solar Cycle 24 back in August, 2006.
Stormy
forecast
Though forecasts vary
wildly, some scientists predict Solar Cycle 24 will be intense. If so,
"it could have significant impacts on telecommunications, air traffic,
power grids and GPS systems," according to the NASA statement.
The peak is
expected in 2011 or 2012. Intense storms can occur at any time in the cycle,
however, though the worst is not likely to begin anytime soon.
"We still have some quiet times
ahead," Hathaway said.
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