The sun is alive. And sometimes it gets angry.
The radiation from Monday's flare, known as a Coronal Mass Ejection, should pass the Earth today, Friday and Saturday. The charged particles will speed by at some 560 miles per second.
Do not be afraid. NOAA's Space Weather Prediction Center in Boulder, Colo., says the Earth is well-protected by its atmosphere and magnetic field. When solar radiation picks up, the most dramatic effect is usually a brightening of the aurora borealis, the famous northern lights in the sky over Arctic regions. After a big flare they are sometimes visible in the northernmost of the 48 contiguous states.
What makes this storm interesting, said Joe Kunches of the Space Weather Prediction Center, is that there were actually three flares in succession -- and radiation from the last and biggest of them is travelling faster than the particles from the first two.
"What's the effect of the triple punch?" said Kunches. "Stay tuned."
Outbursts such as the current one are actually quite common, scientists say. But modern technology can be sensitive to solar storms; scientists say satellites, power grids and communications networks can suffer outages.
"Each time we use a cell phone or pager, check a GPS locator, turn on a light, or take an over-the-pole flight, space weather could have an effect," said Jack Hayes, director of NOAA's National Weather Service, in a press statement. The Space Weather Prediction Center is part of his operation.
The sun's activity, which follows 11-year cycles, last peaked in 2002 and is now apparently picking up again, headed toward its next predicted crest in 2013. A 2008 National Academy of Sciences report tried to warn that we are not prepared for the biggest -- albeit rarest -- solar storms, which it said could cause 20 times more economic damage than Hurricane Katrina.
In 1989 there was a nine-hour power blackout in most of Quebec -- and people were surprised when scientists later said a solar flare had probably caused it by overloading circuits. In 2000, pager traffic in the U.S. was knocked out for a day, apparently because of a communications satellite that got fried by solar radiation.
This week's storm is unlikely to come close, Kunches said, but there may be sporadic power outages, and radio communications may be affected. Airlines routinely redirect planes on polar routes to stay further south than usual when a solar storm is in progress; if they are more than 82 degrees north of the equator, their radio links can get spotty.
"Our star is waking up again," said Kunches, "and starting to do what we expect it to do."