Scientists Grapple Over Deadly Sunspot Cycle
Pastor Dale Morgan
Scientists Grapple Over Deadly Sunspot Cycle*
By ALICIA CHANG
AP Science Writer
SAN FRANCISCO (AP) -- Scientists are deadlocked over the severity of the
next sunspot cycle, which could produce powerful solar storms that can
disrupt communication systems on Earth.
A panel of space weather forecasters has been sifting through about
three dozen predictions from 15 nations that differ widely in how
intense the next solar cycle will be. The group, run by the National
Oceanic and Atmospheric Administration and funded by NASA, aims to make
an official prediction in spring 2007.
While scientists have observed sunspots - dark, cool blemishes - on the
sun's surface since the days of Galileo, they've been unable to
accurately forecast the severity of the eruptions associated with the
spots. Sunspots are best known for triggering solar flares.
The debate over the next cycle, known as solar cycle 24, has been
"passionate," said Douglas Biesecker, a physicist at NOAA's Space
Environment Center who heads the panel.
No clear prediction has emerged yet from the various computer models
that simulate the sun's activity, Biesecker said Tuesday during a
meeting of the American Geophysical Union.
Forecasts vary so wildly that predictions for the peak sunspot number
range from 42 to 185.
"You have scientists who each have their own idea of what the cycle is
going to be and everybody believes they're right," Biesecker said.
Governments and companies increasingly rely on space weather forecasts
to guard against possible failures of power grids and radio
communications when solar storms explode with massive bursts of magnetic
energy and radiation that barrel toward Earth at millions of miles per hour.
Solar activity occurs when the sun's magnetic field lines twist and turn
as it rotates. The process spews out millions of tons of superheated
charged particles into space.
Scientists at the National Center for Atmospheric Research made
headlines earlier this year when they predicted that solar cycle 24 will
be between 30 percent and 50 percent stronger than the current one and
will begin a year later. The researchers based their forecast on a
sophisticated computer model that others contend has not yet been proven
reliable.
The intensity of the next sunspot cycle could have consequences for the
aging Hubble Space Telescope, which has beamed back stunning images of
star births and galaxies, said Dean Pesnell, a project scientist at
NASA's Goddard Space Flight Center who predicts a weak solar cycle.
A weak cycle would mean that Hubble would experience less atmospheric
drag and stay in orbit longer while a strong cycle could force NASA to
boost the telescope so that it stays in place, Pesnell said.
David Hathaway, a researcher at NASA's Marshall Space Flight Center who
predicts a strong sunspot cycle, said the biggest hurdle is trying to
forecast how the sun will act with little data to work with.
"It's like listening to a freight train in the distance to estimate the
size of the train," Hathaway said.
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