Surprising Aurora Puts On Great Show Last Night

Auroral arcs are topped by red rays light up the northeast while the moon (0verexposed) and Jupiter shine off to the west in this photo taken last night over a small lake north of Duluth, Minn. Both moon and aurora light are reflected in puddles on the ice. Credit: Bob King

No, it wasn’t in the forecast but just the like real weather, the unexpected happens. A change in the “magnetic direction” of the wind of particles from the sun called the solar wind from north to south made all the difference. Earth’s magnetic field points northward. When the field associated with a batch of plasma from the sun points southward, as it did beginning early yesterday evening, there’s a good chance it will link into our field and ultimately allow those particles passage into our upper atmosphere.

A large red patch briefly glowed above the bright green arc around 11:15 p.m. last night May 3. The color was dimly visible with the naked eye. Credit: Bob King

Spiraling down magnetic field lines like firefighters on a firepoles, billions of tiny solar electrons strike oxygen and nitrogen molecules in the thin air 60-125 miles up. When the excited atoms return back to their normal rest states, they shoot off niblets of green and red light that wash the sky in multicolor arcs and rays.

The whole northern sky lit up with green and red rays earlier this morning. While the green color was easy to see, the red was very pale. The human eye is much more sensitive to green light than red, one of the reasons why the aurora rarely appears red except in a camera during a time exposure. Credit: Bob King

Nothing in the space weather forecast would have led you to believe northern lights were in the offing for mid-latitude skywatchers last night. Maybe a small possibility of a glow very low on the northern horizon. Maybe. Instead we got the full-blown show with auroras of many forms jumping, glowing and dancing all night long. When I finally hit the hay at 4 a.m. flames of moderately bright aurora still rippled across the north.

So what about tonight? Just like last night, there’s only a 5% chance of a minor storm. Like I always say, take a look anyway, because nature always has a surprise or two up her sleeve.

9 Responses

  1. Fascinated

    Curious – here in Tallahassee we are only getting a crescent moon but yours is full.. ?

    1. astrobob

      It only looks full because it’s exposed to show the fainter aurora. To show a crescent I’d have to shoot at less than a second.

  2. Troy

    I love that first picture. The reflection off of Superior is really awesome. Hopefully I’ll get up to Superior this summer (just in case I’ve forgotten what cold is!)

    1. astrobob

      Hi Troy,
      Thanks! I almost didn’t take it figuring the moon would be way too glary with a 25-second exposure, but it worked. It actually not Lake Superior though – it’s a small lake named Eagle.

      1. Richard Keen

        Bob, so Eagle Lake is frozen with puddles. Can spring be far behind? Better tell the lake it’s May!
        Beautiful shot, reflections and all.
        How’s Superior doing – still shore ice or ice bergs?

        1. astrobob

          Hi Richard,
          Thanks! Even I was surprised when I got there. It was windy night, so I figured on blurry reflections, but the lake was still ice covered. Still plenty of ice on Superior in the Duluth area, but if you drive up to Knife River, it’s gone from the shore. Last Thursday, seven ships were either waiting to get through it or were stuck in the ice. The Mackinaw icebreaker had to create an open channel.

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