The Northern Lights, or aurora borealis, are one of nature’s most spectacular light shows, captivating viewers with their dazzling displays of swirling colors in the night sky. Many students at the University of Connecticut saw the spectacular show here, but why do they happen and when can we expect to see them again?
According to the NASA Space Place page, the aurora borealis occurs when charged particles from the sun, known as the solar wind, collide with gases in Earth’s atmosphere. These particles are primarily protons and electrons, ejected during solar storms or flares. As they reach Earth, they are drawn toward the poles by the planet’s magnetic field. These collisions release energy in the form of light, creating the shimmering greens, purples, reds and blues associated with the aurora.
Traditionally, auroras are seen closer to the magnetic north and south poles. Places such as northern Scandinavia, Canada and Alaska enjoy them more frequently. However, the lights can occasionally extend further south into parts of the United States when solar activity is particularly strong. That’s what happened last week — the National Oceanographic and Atmospheric Administration (NOAA) and their Space Weather Prediction Center measured a G4 level coronal mass ejection, which is classified as a more severe magnetic storm. The lights could be seen as far south as Alabama and California; storms with smaller G classifications are weaker and less likely to be seen in the United States.
“Eventually, solar flares make their way toward Earth…but [our] magnetic field deflects the solar flares, and we see these cycles where the sun is more active, and right now we’re in one of those periods — expected to end in 2030, but it will peak next year,” explained Scott Gagliardi, a meteorologist for WFSB Channel 3 Hartford.
The KP index, or geomagnetic activity rating, is also used to describe the level of intensity and the location of activity in comparison to the poles, according to NOAA– the most recent storm had a KP rating of 8-9. The agency says that aurora forecasts with this rating “…are the events that create the best aurora and the extended auroral oval will be observable by the most people.”
The National Weather Service (NWS), also a division of NOAA, warned that technological infrastructure may be affected by storms of this magnitude — with the possibility to affect satellite operations, GPS navigation and marine radio and wayfinding equipment. Without the proper institutional preparation, the electricity grid and communications such as cell phone towers and air traffic control may also go down, said David Wallace, a professor of electrical engineering at Mississippi State University, in an interview with CBS News.
To see if it will be possible to see the aurora again, the Space Weather Prediction Center offers an online forecast tool with imagery centered around both poles, and color-coded probability maps. Connecticut is advantageously located in the Northeastern United States, which opens a possibility of seeing the northern lights with at least a G3 rating, and KP index of at least 7. The Aurora Dashboard webpage lists the most recent KP index readings and a three-day outlook.
Clear skies, minimal light pollution and a dark location are necessary for the best chance of spotting the phenomenon, said Chris Bouzakis, a meteorologist with WWLP Channel 22 Springfield. “If you get away from city or town lights and look north you might have a chance to see the rare astronomical phenomenon,” he said.
Even if there is a space weather event that is strong enough, Connecticut may not always be able to see the northern lights — the Aurora Dashboard’s viewline forecast shows visitors the boundaries of where northern lights will be most likely to be visible.
When the next solar event is on the horizon, the National Weather Service office in Norton-Boston, Mass. will make announcements to radio and television station weather teams, as well as on social media. That office also oversees Connecticut weather in conjunction with NWS New York.
For more information about the science behind aurora borealis and other weather events, visit spaceweather.gov and weather.gov/box.