Sunspot's eruption could make for brilliant Northern Lights show Friday


Another storm is headed our way. But this one's not coming from North Dakota or Canada.

The National Oceanic and Atmospheric Administration's Space Weather Prediction Center tells us a geomagnetic storm is likely to hit the Earth's magnetic field Friday, which could make for some brilliant Northern Lights shows farther south than they're typically visible.

Experts say the eruption of a sunspot directly facing the Earth (sunspot AR2158, for those of you keeping track) caused the ultraviolet flash pictured above in a photo from NASA. says the eruption caused a solar flare. And not your run-of-the-mill flare, folks. We're talking about an X1.6-class flare.

Thankfully, the Canadian Broadcasting Corporation translates by telling us that in the Richter Scale of solar flares, that's one of the brightest possible.

Strong flares like that produce something called a coronal mass ejection, or CME. This is essentially a set of gas bubbles threaded with magnetic field lines (thanks, again, CBC).

SpaceWeather says the sunspot's eruption on Tuesday lasted for six hours and the ensuing CME left the blast site at the speed of 2.2 million miles per hour. Here's what it looked like from the Solar and Heliospheric Observatory.

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At the speed it's moving, this geomagnetic storm is likely to reach the Earth early Friday and continue into Saturday, NOAA says in its alert (scroll down to serial number 116).

While most of the storm cloud is poised to miss the Earth, even a glancing blow should be enough to make auroras visible at latitudes that include Minnesota, Michigan, and Maine and may reach as far south as Wisconsin, New York, and Washington state, NOAA says.

SpaceWeather says in recent weeks minor CMEs have produced beautiful auroras in the Arctic Circle and offers a gallery of photos.

The one at right was taken from Hella, Iceland, on Wednesday.

Geomagnetic storms may give us pretty pictures, but they can also cause problems for Earthlings. The CBC notes they affect radio communications and in some cases can knock out satellites, power grids, and navigation equipment on airplanes.

As the Washington Post reports, NOAA expects a storm of the size headed our way Friday could set off voltage alarms at high latitude power systems and could cause transformer damage if it lasts long enough.

Already this year, Minnesotans have been treated to some striking Northern Lights shows, such as one visible in the St. Cloud area in June and one that reached Duluth in February.

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