Want to wow your friends and family on your next visit to Alaska? We’ve made it easy with a roundup of little-known facts about the aurora borealis, or northern lights, that will make you look like a naturalist of the northern latitudes.
Legends of the lights
As these awe-inspiring curtains of green, purple, blue and red dance and ripple across the night sky, uncover their poetic underpinnings in stories from the past. Native American tribal legends offer many accounts for the northern lights, including many tails of life after death and spirits living in the night sky.
In Norway, some myths say the flashing, pulsing lights are caused by the Valkyrie as they ride across the sky in full armor. As light glints across their helmets, spears, and breastplates, it creates the display we know as the northern lights.
Galileo gets credit for naming the aurora borealis upon seeing a light display around 1620. Aurora is the Latin for “dawn,” and it also refers to the Roman goddess of the dawn. Borealis is the Greek term for “north wind.”
People have debated for centuries as to whether the spectacular light displays of the aurora borealis are also accompanied by noise. Scientists at Aalto University in Finland settled the matter in 2012 when they published a paper claiming that they recorded a clapping sound with the lights. Listen carefully, though – it’s an incredibly rare, once-in-a-lifetime opportunity to experience the audio version of the northern lights.
The aurora borealis rides atmospheric currents that measure up to 50,000 volts and up to 20 million amperes. Compare that to your home, where the current maxes out at 120 volts.
Although the aurora borealis is normally only visible near the magnetic north pole, residents of southern Canada and the lower 48 occasionally get a visual treat in the nighttime sky. In February, 1958, there was a display circling 1,250 miles, from Oregon to New Hampshire. At other times, sightings have been reported as far south as Cuba and Mexico.
Earth, solar wind and fire
The dance of the aurora borealis begins when the sun ejects a gas cloud filled with highly charged electrons. This coronal mass ejection, as it’s called in scientific circles, takes up to three days to ride the solar winds to Earth’s atmosphere. Once in our corner of the solar system, those electrons collide with atoms of oxygen and nitrogen in the Earth’s atmosphere, producing the pulsing, shimmering light show that we know as the northern lights.
Color me dazzled
Why do the lights display green one night, purple the next, and red or blue on another? The hues are created by the collision of highly charged electrons with oxygen and nitrogen in our planet’s upper atmosphere. The color depends on which atom is struck, and how high.
Blue = nitrogen, up to 60 miles above Earth’s surface
Purple = nitrogen, more than 60 miles high
Red = oxygen, up to 60 miles high
Green = oxygen, up to 150 miles high
Need to know
The aurora borealis is a breathtaking sight, whether you see it for the first time or the 500th. After you’ve breathed in the Alaska awesomeness—and listened closely for the lights’ elusive clapping sound—lean into the lessons of science. Your encounter will be that much more memorable if you bring your inner nerd on your trip north.