Sky watchers with clear skies across Canada, the northern United States, and other northern latitude countries should be on the lookout tonight for possible flare-ups of the aurora borealis.
The celebrated northern lights already put on a great show late Tuesday night for folks from Alberta to Ontario and in European countries such as Estonia, Denmark, and Germany. Earth’s bubble-like magnetic field was hit so strongly by charged solar particles that auroras were even seen farther south than normal, in places like Maine, Minnesota, and Wyoming.
Now, forecasters are predicting at least a 55 percent chance of a repeat performance, possibly with even more flashy auroras.
All this sky action is caused by a strong gust of solar wind that erupted off the sun’s surface this past weekend. Space weather satellites, which keep tabs on solar activity 24 hours a day, provided advance warning that the burst of charged particles would slam into Earth.
Such solar eruptions are called coronal mass ejections, and they release massive clouds of charged solar particles many times larger than our planet. The clouds travel at immense speeds and can reach Earth’s orbit in a matter of days.
When the particles hit Earth's magnetic field, they create disturbances known as geomagnetic storms. On rare occasions, such storms can damage electrical grids and temporarily knock out radio and satellite telecommunications. Any communications loss could also cause air traffic controllers to re-route long-duration plane flights over the Arctic. Staff at the U.S.-based Space Weather Prediction Center say that they are closely monitoring the situation and are updating forecasts as needed.
Geomagnetic storms also naturally funnel solar particles down into our atmosphere through the Poles. The particles then smash into oxygen and nitrogen molecules, infusing them with energy and causing them to glow, giving birth to colorful auroras.
Here is our quick guide to catching this week’s northern lights show:
Who will get to see the sky show?
The strength of the display depends on the orientation of the CME's magnetic field when it arrives, and that is hard to predict.
According to current reports on Spaceweather.com, scientists are forecasting at least a 55 percent chance of intense auroras occurring in higher latitude skies, and around a 35 percent chance for mid-latitudes.
So if you have clear skies and you live north of 40 degrees latitude—that's anywhere north of the line stretching from Philadelphia to Denver, roughly speaking—it's worth a peek outside the next few nights.
Sky watchers around the Arctic Circle will most likely see something, and those in more mid-latitude locations—like Toronto, New York, Seattle, and London—may have a fair chance as well.
While the best place to catch auroras are dark locations away from city lights, intense displays can on rare occasions become bright enough to be easily seen from suburban backyards or even from the window of a darkened bedroom. Just remember, as with any stargazing, to turn off all your lights and give your eyes at least 20 minutes to adapt to the darkness.
When is the best time to look up?
The best time to look north is starting at mid-evening and continuing late into the night. Generally, auroras start to kick in around local midnight, but since this is an intense event, the first hints of auroras may begin soon after local nightfall.
Watch for a greenish glow to creep up the sky from the horizon—that's how many aurora events begin. If it ends up being an intense display, then a larger portion of the sky will unveil orange, pink, and purple curtains waving overhead.
How do I take a photo of the auroras?
You may want to try your hand at capturing your own souvenirs of these ghostly glows. It's not rocket science, but you have to have the right kind of equipment, an eye for framing your shots, and some patience. Some of the most beautiful photos of auroras are set where foreground objects such as houses, trees, and mountains are in view.
You should have a digital SLR camera with a wide-angle lens (55mm or less) to capture as much of the sky and landscape as possible. Mounting your camera on a sturdy tripod is a must, as you’ll need a stable platform to take long-exposure photos.
Your camera should have a manual setting where you can set the exposure rates at up to 20 to 30 seconds. Boost the sensitivity of your camera sensor to 400 ISO or higher. Both long exposures and higher ISOs will allow you to pick up hidden details and colors of auroras that you can't see with the naked eye. A self-timer release is indispensable as well, as it will allow you to remotely trigger shots without shaking the camera.
Remember to be patient, because auroras can take anywhere from minutes to hours to unfold—and you never know when you may see that awesome colorful curtain of light appear.
Finally, don't be afraid to experiment with camera settings—and expect to take scores of snapshots before you catch any keepers.
While there are no guarantees that there will be auroras, the only way to know for sure is to go outside and look for yourself.