There's a myth about the sun. It begins with a true story:

Every 11 years solar activity surges. Sunspots pepper the sun, and they
explode, hurling massive clouds of gas ("CMEs") through the solar
system. Earth gets hit by X-rays and protons and tangled knots of solar
magnetism. Astronomers call this solar maximum---or "Solar Max," for
short.

The most recent solar maximum, in 2000 and 2001, was spectacular. Sky
watchers saw auroras around the world---even in Florida and Mexico;
astronomers marveled at huge sunspots and the flares they unleashed;
satellite operators and power companies struggled with outages.

Things have quieted down since then. Sunspots numbers are declining as
the sun heads for the opposite extreme of its cycle, solar minimum. At
lowest ebb, expected in 2006, the sun will be (here comes the myth)
*absolutely quiet*.

"Don't count on it," says solar physicist David Hathaway of the NASA
Marshall Space Flight Center. "The 'quiet sun' can be pretty active."

Even during solar minimum, he explains, the sun produces big sunspots,
it unleashes the most powerful kind of "X-class" solar flares, and sky
watchers can see auroras. All these things happen, "just not so often."

Hathaway has counted the number of X-class solar flares during the last
three solar cycles, a period spanning 1970 to the present. "The number
of flares during solar minimum is low\--but *not* zero. In fact, during
the absolute rock-bottoms of the last three solar cycles, there was at
least one X-class solar flare."

This means astronauts traveling through the solar system, far from the
protection of Earth's atmosphere and magnetic field, can't drop their
guard---ever.

Hathaway offers this example: Rewind to January 10^th^, 2005. It is four
years since Solar Max and the sun is almost blank---only two small
sunspots are visible from Earth. The scene is typical of solar minimum.

Then, on January 11^th^, a new 'spot appears, at first much like the
other two, small and unthreatening. Forty-eight hours later it blossoms
into a giant almost as big as the planet Jupiter. "What a surprise!"
recalls Hathaway. Between January 15^th^ and 20^th^, the sunspot
unleashes two X-class solar flares, sparks auroras as far south as
Arizona in the United States, and peppers the Moon with high-energy
protons. Lunar astronauts caught outdoors would've likely gotten sick.

So much for the quiet sun.

It almost happened again last week. On April 27^th^ a small sunspot
emerged over the limb of the blank sun. And then\--déjà vu---it grew
rapidly, becoming many times wider than Earth in only 48 hours. This
sunspot, however, did not erupt.

Why not? No one knows.

Sunspots are made of magnetic fields and when those fields become
twisted and unstable ... bang! Solar flares and CMEs are by-products of
the explosion. The problem is, these fields are devilishly difficult to
predict. Looking at a sunspot's magnetic geography today doesn't
necessarily tell you what it's going to be like tomorrow---or even an
hour from now. Sometimes, a solar storm hits Earth with only 10 minutes
notice. Researchers like Hathaway are studying sunspots, hoping to
improve forecasts, but much work remains.

Predicting solar activity, even during "quiet times," is more important
than ever. Not only do we depend increasingly on sun-sensitive
technologies like cell phones and GPS, but also NASA is planning to send
people back to the Moon and, then, on to Mars. Astronauts will be "out
there" during solar maximum, solar minimum and all times in between.

Will the sun be quiet when it's supposed to be? Don't count on it.