BY KATE MILEWSKI
TRAVERSE CITY — Northern Michigan residents who spied the night sky this week were treated to quite a display: a dance of aurora borealis.
“It went from a green band to this incredible, amazing display,” said Bob Simmerman, who lives near Lake Ann and watched the lights Tuesday at about 10:45 p.m. “It lasted maybe 10 minutes.”
The show began early in the evening and lasted well past midnight. Experts pegged the event a six on a scale of zero through nine, and believe it could be just the start of what could be a landmark year for star gazers.
“We definitely had a nice display,” said Jerry Dobek, a Northwestern Michigan College professor of astronomy. “We’ve got quite a few active sun spots right now; we’re getting up into its peak time.”
Peak time occurs once about every 11 years and means increasingly more sunspots face the Earth. Sunspots cause solar flares that send out coronal mass ejections. Charged particles are pushed into space and, as they pass close to Earth, become attracted to the magnetic poles in the north and south.
The closer a viewer is to the magnetic pole, the more intense the lights.
Tuesday’s event came as a bit of a surprise to forecasters who expected a smaller display.
“It was a bigger storm than we forecasted,” said Rodney Viereck, director of space weather prediction test bed at the National Weather Service.
Predicting when northern lights may be viewable can be a tricky business. Scientists like Viereck look for coronal mass ejections leaving the sun and they try to predict speed, direction, arrival time and size of the storm.
“We get arrival time pretty good, but we’re still struggling to predict how big the storm will be,” he said.
The sun’s stint in the solar maximum part of its cycle — a period that’s expected to last until 2013 — indicates strong solar flares and more activity on the aurora front, experts said.
Small activity is anticipated Thursday night and another spike in auroras should come about in 27 days.
Some negatives blemish the night show’s beauty. Such flares can interfere with communication satellites and power grids.
“The same things that cause the northern lights are hazardous for those on the space station, so we monitor them very closely,” Dobek said. “Some are strong enough that they can destroy a satellite if they charge it with enough energy. Astronomers keep an eye on things to keep the satellites operating.”
Traverse City area residents shouldn’t have trouble seeing another example of the northern lights in early December and beyond, if the sky is clear.
“You’re in a good position,” Viereck said. “We should be able to see the aurora two to three times a winter with no problem at all. But it’s like predicting the weather, there are no guarantees.”