For the next year, the night skies will provide some of the best opportunities to see the Northern Lights (Aurora Borealis) for the next decade.
The Northern Lights are one of the seven wonders of the natural world, and for centuries, they were one of the greatest mysteries of the world as well. Long after we understood the path of the orbiting planets and were able to predict solar and lunar eclipses, we still failed to see the reasons and natural patterns that brought us the Aurora Borealis.
The displays of dancing lights in the sky have therefore long fueled folklore and superstitions, especially when the typically far northern phenomena became visible far from its normal domain. One such classic example occurred during the Civil War, Battle of Fredericksburg, when as soldiers lay dying in the field from a particularly bloody battle, they looked up to a blood-red sky, a clear sign from God against the opposing army.
We now know why the northern lights made such a prominent display that fateful night, and moreover, we can predict, both in the long and short-term, when we expect displays like this to occur again. We have learned that strong displays of the aurora are tied to a solar cycle first discovered in 1843, using a data set dating back to the scientific revolution.
When Galileo pointed his early telescope towards the sun around 1600, he became the first European to observe a sunspot, which appeared as a dark area on the disk of the sun. He kept a faithful daily journal of sunspots throughout his life, and encouraged others to do the same, which eventually led to the discovery of a roughly 11-year cycle of alternating high and low sunspot counts on the sun’s face.
The times of high sunspot activity have now been tied to times of stronger displays of the northern lights, like that in Virginia in 1862, during the peak of ‘Solar Cycle 11.’
We are now nearing the peak of Solar Cycle 24, and the predicted solar maxima will occur early next year. The number of sunspots visible on the face of the sun have increased steadily since 2009, and have already recently caused intense displays of the northern lights over New England.
The reason why is basic science today. Sunspots are actually areas of intense magnetic activity on the sun, which harbor large amounts of energy. This energy can lead to huge solar explosions, called coronal mass ejections (CME’s), which hurl huge quantities of plasma and charged particles into space.
When these charged particles reach Earth, they are steered towards the polar regions by the Earth’s magnetic field, and their interaction with the upper atmosphere leads to the generation of light.
Today, every sunspot that emerges on the sun is intensely studied, and every coronal mass ejection is precisely tracked to predict the impact that it will have on the Earth before it arrives. When a CME leaves the sun, we typically have a few days warning, allowing photographers to check the forecast, and get to a favorable location to view the lights. Such forecasts and warnings are posted daily at a few websites, such as spaceweather.com, spaceweather.gov, and Geophysics Institute at the University of Alaska, Fairbanks.
A few of these sites allow you to sign up for alerts after a solar explosion occurs. Not all CME’s are geoeffective, but the Earth has the greatest chance of being in the path of particles both in September/October, as well as February/March.
Most of the Northern Lights that are visible from New England are dim, and low on the horizon. The best chance for viewing these are either at a location that has a clear view to the north, or an elevated location that can extend the distance that you can view to the north.
However, stronger and more prominent events can allow the lights to extend as far as 60 degrees above the horizon, and in the strongest storm of the last solar cycle, in October 2003, the aurora was directly overhead in New England, and visible as far south as Florida.
Photographing the aurora is not all that different from any other nighttime photography (you can refer to Mike Blanchette’s recent blog posts on the subject). You have to have a clear sky in a dark location, preferably at a time before the moon rises or after it sets.
You should select a high ISO, a long shutter speed and have a sturdy tripod and a shutter release. My best exposures are typically around 30 seconds with a wide-angle lens so as to ensure that the motion of the stars is minimized in the frame.
Already this solar cycle, we have been treated to a few great displays of the Northern Lights, and activity is expected to pick up this fall and continue into the spring. If a storm is predicted, and you have the chance to see it, I’d encourage you to do so, as soon the chances of strong displays will again decrease until the next peak of the cycle in 2024.
~ Jim Salge