G2 Aurora Storm Forecast For March 23 / Space Station Back At Dusk

This photo, taken by NASA’s STEREO-A spacecraft, shows the coronal mass ejection (CME) in progress after a solar flare blew up in sunspot group 2736 (photo below). Most of the material will likely miss the Earth, but we’re expecting a glancing blow, enough to stir up a G2 geomagnetic storm. The sun is covered with an opaque disk to block glare. NASA

Spring brings new vigor to the night sky scene. And the day sky too! After being spotless for weeks, two sunspot groups have popped into view. The larger of the two, named active region 2736, produced a flare early on March 20 that propelled a burst of solar plasma (electrons and protons) toward the Earth. It’s expected to arrive around noon Central Time this Saturday, March 23 and intensify to a G2 (moderate) geomagnetic storm during the afternoon and last into the early evening hours. With moonrise around 11 p.m. local time that night, we should have a good window of darkness for lights viewing.

After many blank days, the sun has its spots back. Today, active region 2736 is easy to see in a small telescope equipped with a safe solar filter. NASA’s Solar Dynamics Observatory took this photo earlier this morning. NASA

A moderate storm usually means that skywatchers across the northern tier of states will see a northern lights display. That could mean anything from a sleepy arc 5-10° above the northern horizon to rays, arcs and pillars stretching and fluttering across the northern half of the sky. Most of the displays we’ve seen in the past year have been stoked by holes in the sun’s corona that allow high-speed solar winds to escape. This one, if it happens, points back to that flare-related burst, which produced a coronal mass ejection or CME.

At the equinoxes, cracks in Earth’s magnetic field are more likely to form. These allow the solar wind from CMEs and the like to find to get past the planet’s defenses and stream down into the atmosphere and excite atoms of oxygen and nitrogen to produce the northern lights.

“We’ve discovered that our magnetic shield is drafty, like a house with a window stuck open during a storm,” says Harald Frey, research physicist at the University of California, Berkeley. “The house deflects most of the storm, but the couch is ruined. Similarly, our magnetic shield takes the brunt of space storms, but some energy slips through its cracks, sometimes enough to cause problems with satellites, radio communication, and power systems.”

This map — from Heavens Above — shows tonight’s space station pass from the Duluth, Minn. region. Chris Peat / Heavens Above

In other news, the International Space Station (ISS) is once again making passes during evening hours. With warmer weather now at hand, this is a happy time to be out at dusk to watch it go by. The space station looks like a bright star that rises in the western sky and travels east. If it’s not eclipsed by Earth’s shadow — when you’ll see it fade and disappear right before your eyes — a complete pass from west to east takes about 6 minutes.

Go outside a few minutes before a pass to get your eyes used to the dark and also to know in what direction to look. The ISS will first appear low in the west, southwest or northwestern sky (depending on the pass) and climb higher and higher into easy visibility.

The current round of passes continues through early April, so you’ll have lots of opportunities. You can find ISS pass times and maps showing its path at Heavens Above. Click the link, select your city and then tap the ISS link for a list of passes for the coming nights. Click on a date to see a map and timeline. Another option is NASA’s super-easy Spot the Station site for times. You can sign up there to get e-mail or text alerts whenever there’s a favorable pass over your city. Or you use an app like ISS Spotter for iPhone or ISS Detector for Android and customize your viewing.

4 Responses

  1. caralex

    And 40 or so minutes later, I see it above New Brunswick, although that’s two time zones ahead of you. I’m actually surprised it takes that ‘long’ to get that distance…or would the time zones actually make a difference?

    1. astrobob

      Carol,
      It only takes minutes to get to you from me. It’s the time zone difference. I once simultaneously saw the space station with a friend living near Seattle, two time zones behind. I was out watching at around 10 p.m. — he was out around 8. We were able to see it simultaneously for about a minute. In the western sky for him and off to the east for me.

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