Solar Radiation
An 11-year epoch of increasingly severe solar storms that could fry
power grids, disrupt cell-phone calls, knock satellites back to
Earth, endanger astronauts in space, and force commercial airliners
to change their routes to protect their radio communications and to
avoid deadly solar radiation could begin as soon as this fall,
scientists announced Monday.
When the solar cycle reaches its peak in 2012, it will hurl at Earth
mammoth solar storms with intense radiation and clouds of high-speed
subatomic particles millions of miles across, the scientists said.
A storm of that magnitude could short-circuit a world increasingly
dependent on giant utilities and satellite communications networks.
Such a storm in 1989 caused power grids to collapse, causing a
five-hour blackout in Quebec.
Monday's forecast was announced by scientists from agencies
including NASA and the National Science Foundation, based on
research centered at the National Center for Atmospheric Research in
Colorado.
There is disagreement on exactly when the new cycle will begin --
one key researcher predicted the cycle will start in late 2007 or
early 2008, and another said it could begin either late this year or
in early 2007. But they did agree that the most severe storms won't
begin popping on the solar surface for several years, but when they
do, they'll be huge.
The solar storms in the past have knocked out huge power grids and
screwed up global electronics and data communications, but "the next
sunspot cycle will be 30 to 50 percent stronger than the last one,"
the scientists said in Monday's statement.
Reaching that 50 percent threshold would make it the most intense
solar cycle since the late 1950s and the second worst since the
early 1700s, Peter Gilman, one of the researchers, said in a phone
interview.
Astronomers will monitor the sun daily in the coming months to see
how it's doing. Early warning signs will be the formation of large
groups of sunspots, which are clusters of solar magnetic fields that
are cooler than the rest of the sun.
"I look (at telescopic images of the sun) almost every day,
thinking, 'It could be today,' " said David Hathaway, solar physics
team leader at NASA's Marshall Space Flight Center in Alabama. He
compared it to "waiting for the first sparrow of spring." Solar
storms can happen at any time during an 11-year solar cycle.
However, by far the worst storms are likeliest to occur during the
period known as "solar maximum," or solar max for short. The last
solar max was in 2001. The scientists are confident of their
forecast for 2012 because they've successfully used a new computer
model to "forecast" the past. That is, they used records of old
solar cycles to figure out how the sun should have behaved during
eight past cycles, as far back as the early 20th century. They
"forecast" the sun's past behavior -- "hindcasting," they call it --
"with more than 98 percent accuracy" the scientists said.
"I'm really excited about this (discovery)," said NASA's Hathaway.
"It's based on sound physical principles, and it finally answers the
150-year-old question: What causes the sunspot cycle?"
The cycle's victims could include space satellites. The coming
storms could heat the upper levels of Earth's atmosphere, causing it
to expand and exert drag on low-flying satellites -- perhaps enough
drag to tug some of them back to Earth. Solar storms have been
blamed for the U.S. Skylab space station's premature fall back to
Earth in 1979.
Air travelers could be affected, too. Since the end of the Cold War,
to avoid headwinds, airlines have increasingly flown sub-polar
routes to get between the United States and other Northern
Hemisphere continents quickly and cheaply. But during solar storms,
they must avoid the poles and fly more southerly routes.
They do so partly in order to avoid having their radio
communications disrupted over dangerous polar terrain and partly to
avoid exposing passengers -- especially pregnant women -- to the
increased radiation, said solar-storm expert Joseph Kunches, chief
of the forecast and analysis branch of the U.S. National Oceanic and
Atmospheric Administration's Space Environment Center in Boulder,
Colo.
The northern and northeastern portions of North America are
historically more vulnerable to system outages caused by solar
storms than California and most of the Western states, said Gregg
Fishman, spokesman for the California Independent System Operator.
That's possibly because among other things, he said, there's a
higher iron and mineral content in the North and Northeast that
conducts the ground current more easily and allows for more of an
impact during solar storms.
