Lights out for this year's aurora
 

"Because of low Solar activity on the Sun, scientists say its lights out for
this year's aurora."

http://www.ktuu.com/Global/story.asp?S=9908401

Fewer northern lights the result of low Solar activity, scientists say
by Ashton Goodell
Tuesday, February 24, 2009

ANCHORAGE, Alaska -- People across the globe come to Alaska to see the
aurora borealis, commonly called the northern lights, but those looking for
an aurora this year will likely only see stars.

Photographers and star gazers travel here to catch a glimpse of the
spectacular burst of color, while others make the journey hoping for the
lights to bring them luck.

But just like the weather, the aurora isn't easy to find or predict.

"It's been several years since I've seen them," said Dusty Moody. "The one I
saw was always green, but little bits of reds and purples are nice to see."

But the northern lights are a result of space weather, and lately the
weather's been dry: Because of low Solar activity on the Sun, scientists say
its lights out for this year's aurora.

"Some people will ask me when should I come to Alaska to see the northern
lights and I say, 'Wait five years,'" said Travis Rector, an associate
professor of astronomy at UAA.

The Sun moves through an ~11-year Solar cycle, and right now activity is at
a grand Solar minimum.

Astronomers have tracked sun spots for hundreds of years, and when those
numbers decrease it usually lasts about one year. But some scientists think
the current trend is part of an extended dip, called a grand minimum.

"These Sun spots are associated with Solar flares," Rector said. "Whenever a
flare erupts, it blows high energy from the Sun and it travels to the earth
and it takes a few days to do that. It hits the earth magnetic field, and
the magnetic field, which protects us, also diverts some of the particles to
the north and south poles."

The lights we see are excited energy particles diffusing in the atmosphere,
but the starting point for the aurora borealis is the Sun spot.

As Sun spots fester on the sun's surface, they're warped by its rotation.

The lines get twisted up, and gas rises to the surface of the sun, creating
the spots.

"When these magnetic field lines get twisted up, they eventually sort of
snap and that causes an ejection of energy particles into space," Recotr
said. "That's called a Solar flare and if it's aimed toward the earth, then
those particles will hit the earth atmosphere and create the northern
lights."

While scientists counted fewer Sun spots for the past three years, the Sun
spots may grow back. For now, it looks like this Solar cycle will be weaker
than all previous years.

Additionally, some scientists say decreasing Solar activity could chill the
earth, forcing global temperatures down, but it's a controversial topic that
others argue could also be explained by volcanic activity or geothermal
changes.

Contact Ashton Goodell at