Keep watch for the northern lights tonight June 1-2

Eric Anderson of Omaha, Nebraska took this gorgeous shot of last night’s display. “Just had an epic aurora borealis photo shoot west of Lyons, Neb. I didn’t increase colors on this at all. 20″ exposure.” Credit: Eric Anderson

Last night’s aurora crept up out of nowhere. Space weather forecasters predicted a very small chance of a minor auroras for mid-latitudes, but a sudden change in the direction of the interplanetary magnetic field (IMF) set Earth’s magnetic field a-jitter, sparking a nice display of northern lights. The storm’s still raging across Siberia this afternoon with no sign of letting up.

The interplanetary magnetic field, created by a wind of solar plasma entwined with magnetic fields, whirls from the sun in the shape of a gigantic spiral. As waves of varying strength, density and direction pass by Earth, our planet’s magnetic field occasionally hooks up with the sun’s, making auroras likely. Credit: NASA

The IMF is a part of the sun’s magnetic field carried into interplanetary space by the solar wind, a high-speed outflow of subatomic particles, mostly electrons and protons. Scientists call this soup of charged particles a plasma. Because the sun rotates, solar plasma travels away from the sun in grand spirals much like water spraying from one of those rotating lawn sprinklers.

Click to watch a video of the solar wind linking up with Earth’s magnetic field behind the planet, sparking a particle cascade and auroras in our upper atmosphere.

Embedded within the sun’s plasma swirls are portions of its magnetic field. As the IMF sweeps past Earth, it normally glides by, deflected by our protective magnetic field, and no one’s worse for the wear. But when solar magnetic field points south – what’s called a southward Bz – it can hook up with Earth’s northward-pointing magnetic field. Once linked, the IMF dumps its baggage of high-speed particles into our atmosphere to light up the sky with aurora and set satellite operators on edge.

That’s exactly what happened yesterday evening. The Bz turned sharply south and Earth’s private space was invaded by a particle horde. Coronal mass ejections and constant fluctuations in the solar wind can tip the Bz this way and that and set the scene for northern lights.

Last night’s bright aurora photographed from Beecher, Wis. by Brian Larmay. Click to see more aurora pix on his website.

Last night’s storm rated a G2 or moderate on NOAA’s space weather scale. G2s not only produce auroras but can cause fading of radio transmissions at high latitudes, drag on satellites and even trigger voltage alarms on power grid stations.

The aurora often begins as little more than a low, greenish arc in the northern sky. If conditions are right, multiple arcs and rays can form and sometimes fill the entire sky. Photo: Bob King

The aurora will likely continue through this evening, so be on the watch. Check the Kp index and if it’s up to “5″ or higher (in the red zone), chances are decent you’ll see aurora at least from the northern U.S. Another cool tool is the Ovation aurora site that displays a beautiful graphic representation of the complete auroral oval. When you see the oval’s edge creep up to or over the northern U.S. auroras are almost certain to show. Of course you’ll need a clear sky, which is often the trickiest thing to find.

How about mixing your aurora up with a nighttime thunderstorm? Rob Rustvold shot the spectacular dual display along the northern horizon in Fort Dodge, Iowa last night. Credit: Rob Rustvold

I’ll update the blog this evening if and when auroras come back to green-wash the sky.

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About astrobob

My name is Bob King and I work at the Duluth News Tribune in Duluth, Minn. as a photographer and photo editor. I'm also an amateur astronomer and have been keen on the sky since age 11. My modest credentials include membership in the American Association of Variable Star Observers (AAVSO) where I'm a regular contributor, International Meteorite Collectors Assn. and Arrowhead Astronomical Society. I also teach community education astronomy classes at our local planetarium.

12 thoughts on “Keep watch for the northern lights tonight June 1-2

  1. Bob, with the cloud cover tonight… what’s are the odds of seeing auroras tonight up in duluth? Thanks, Nick!

    • Nick,
      It doesn’t look like it will clear off until about 1 a.m. Watch the Kp index and live oval updates before you decide to come up. It’s just so hard to predict whether the current storm will be fading then or cranking up again.

    • Linda,
      Activity is low right now but may pick up later in the day. If you see the Kp index push up into the red zone – level 5 or higher – yes, you might see aurora from MA.

    • Sorry for the late reply Daniel. There were northern lights but they only appeared as a single, odd arc that faded and grew back over several hours. Very peculiar.

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