Jan. 21, 2012 at 4:59 PM ET
Last updated 1:45 p.m. ET Jan. 22:
Forecasters say a blast from the sun should strike a glancing blow to Earth's magnetic field, starting Sunday, and create a mild geomagnetic storm. That's not enough to pose a planetary threat, but the storm should spark better-than-usual auroral displays. Skywatchers are already getting some great pictures in advance of the peak.
The blast, known as a coronal mass ejection, was witnessed by sun-watching spacecraft on Thursday — and at the time, NASA projected that the geomagnetic impact on Earth would be felt today. But experts at the National Oceanic and Atmospheric Administration's Space Weather Prediction Center in Colorado say the peak will come later.
"We're looking at it to start on Sunday, about 1 o'clock [p.m.] Eastern time," Joe Kunches, a space scientist at the prediction center, told me today.
The storm of electrically charged particles is projected to take a relatively non-threatening path past our planet. "We think it'll go to the north of Earth ... rather than right at us," he said.
The center's prediction projects that the "bulk of the disturbance" should occur on Monday. But even then, the storm will be a G1, which is the lowest ranking on the scale of geomagnetic activity. Such a storm generally produces weak fluctuations in electrical grids and has the potential for minor effects on satellite operations — basically, nothing for regular folks to worry about.
The main effect is expected to be bright northern lights that could be visible farther south than usual. In northern regions, aurora aficionados are already seeing some fantastic fireworks. Keep watch up above, particularly if you're in an area with clear, dark skies. Keep watch for updates in SpaceWeather.com's January aurora gallery as well. The Canadian Space Agency has its AuroraMAX webcam working in the Northwest Territories, and you can even sign up for updates via the project's Twitter account, @AuroraMAX.
Update for 1:45 p.m. ET Jan. 22: The Space Weather Prediction Center is showing a rise in solar particle flux, and European observers are passing along some great pictures. Among the places to check, in addition to SpaceWeather.com, are the Aurora Sky Station in Sweden, the Facebook page for Iurie Belegurschi Photography in Iceland and this awesome Vimeo video (plus Flickr page) from Norway (play it at full screen for full effect):
Have you come across other websites or pages on Facebook or Google+ with great sights of the northern lights? Feel free to pass them along in your comments below. One caveat, though: Newbies may not have the capability to pass along Web links, so you might have to spell them out, as in www-dot-cosmiclog-dot-com. And as always, be cautious when clicking on external links.
More great auroral views: