Aurora borealis over Jökulsárlón Glacier Lagoon in southern Iceland, March 18, 2015. (Photo provided — European Space Agency, Carlos Gauna)

In late October and earlier this month, spectacular aurora activity was visible across much of the northern hemisphere. Sightings were reported from Maine to Washington state and as far south as Connecticut and California.

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Aurora activity?

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The term aurora borealis was first used by the Italian astronomer, Galileo Galilei. Translated from the Latin, it means “red dawn of the north.”

The aurora borealis is centered on the north magnetic pole. Auroras centered on the south magnetic pole are known as the aurora australis or the southern lights.

But what exactly is an aurora?

Why, the wrath of angry gods and tempestuous demons, of course. At least that was the popular belief until the early 1600s, when philosophers proposed, instead, that auroras were vapors being exhaled by the Earth. It wasn’t until the 1700s that scientists began noting the magnetic properties of the Earth and theorizing about magnetic particles flowing through the air.

Today, scientists know that auroras originate at the Sun, along with life-giving light and heat. Subatomic particles, mostly electrons, are endlessly being discharged at very high speed from the sun’s hydrogen atmosphere. This stream of highly charged particles is called the solar wind.

As these particles approach the Earth, they’re drawn into the planet’s magnetic field, where they collide with gasses in the atmosphere. The outcome is an emission of waves of light called photons. The collisions can occur in great, even countless numbers. And, when that happens, the end result is an aurora.

The principle is somewhat similar to what happens in a neon light. As electricity runs through the glass tube, or bulb, the neon gas inside becomes charged; excited; and emits a bright light.

Solar flares and storms

Solar flares are violent explosions, or eruptions, that emanate from the outermost layer of the sun’s atmosphere; the corona, throwing subatomic particles into space at velocities approaching the speed of light. Solar storms, or coronal mass ejections (CMEs) are even more violent — releasing massive clouds of plasma and their associated magnetic fields into space at speeds far-surpassing a million miles an hour. These disturbances can be more than a million miles wide and can infuse tremendous amounts of energy into the Earth’s magnetic field as they hit, seriously upsetting balances of trapped magnetic particles within the field and interfering with crucial infrastructure, including power grids, navigation satellites and airplane radio communications.

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Potential consequences

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On Oct. 28, a “strong radio blackout event took place” at 11:35 a.m. EDT, when an Earth-directed CME pushed a billion tons of solar material and a magnetic field out into space, according to the National Oceanic and Atmospheric Administration. The solar plasma sped toward Earth at roughly 3 million miles an hour.

During October / November of 2003, solar flares and CMEs of a magnitude never seen before, or since, caused spectacular aurora activity around the world. Experts call the period one of the stormiest in recorded history. Enormous solar flares produced Earth-directed CMEs that affected numerous Earth-orbiting satellites. NOAA’s Geostationary Operational Environmental Satellite, which monitors flare activity, was rendered non-functional for 11 minutes. And Kodama, a communications satellite owned by the Japanese Aerospace Exploration Agency, was permanently damaged. Airline flights traveling over the North Pole experienced communications problems that disrupted operations. Antarctic science groups sustained a full communications blackout for more than 130 hours. And GPS systems used for surveying and deep-sea and land drilling were seriously affected as well.

At the height of the storms, astronauts aboard the International Space Station had to shelter themselves from high radiation levels and, in an historic first, the United States Federal Aviation Administration issued an alert warning airline passengers that they could be exposed to abnormally high levels of radiation at altitudes greater than 25,000 feet.

Solar storms can wreak havoc on power grids, too. In August of 1972, shifting magnetic fields caused a 230,000-volt British Columbia Hydroelectric Authority transformer to explode. And on March 13, 1989, Canada’s Quebec province was thrown into darkness because of a solar storm.

Magnetic storm currents created by auroras are known to fuel corrosion in pipelines as well, including the trans-Alaska pipeline, and are considered responsible for corrosion that resulted in a gas pipeline explosion that destroyed a section of the Trans-Siberian Railway, on June 4, 1989.

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Auroral inspirations

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The northern lights have captivated the imaginations of artists, spiritualists, sages, and scientists for centuries. Some viewed auroras as omens of war and sickness. Others found comfort and promise in their very existence.

Early Chinese legend associated the aurora with fire-breathing dragons battling each other across the nighttime sky. In Norse mythology, the northern lights were described as reflections from the shields and armor of women warriors, the Valkyrie, who chose who may live and who may die in battle, and as the arch that led the fallen to their final resting place, in Valhalla. Finnish legend maintained that the lights were caused by the firefox, who ran so quickly across the snow that sparks from its tail could be seen in the night sky. The Estonians believed the lights were magnificent horse-drawn carriages carrying the gods and their guests to a celestial wedding.

Among the indigenous people of North America, legends are many. Some tell of dancing human and animal spirits. Others of friendly giants and supernatural dwarves. Algonquin elders told their children that the northern lights were the reflection of fires built by Nanabozho, the creator, to assure his people that he would never forget them.

Certainly, the splendor of the northern lights will continue to inspire writers, artists, observers, medicine men, warriors, spiritual thinkers, and scientists for a long time to come.