Galileo Galilei coined the term “Aurora Borealis” after the Roman goddess of dawn Aurora and the Greek god of the north wind, Boreus, after looking up in 1619 to see the night sky streaked with green and purple light. However, Galileo was not the first to marvel at the northern lights.

Perhaps the earliest depiction of the Northern Lights can be found in a cave in southwestern France, where 30,000-year-old fingerprints mimic the twists and turns of the star light show. King of Babylon II in 567 BC. Two thousand years later, a huge spectacle blazed above the modern Czech Republic, which artists depicted as burning candles above the clouds.

Just a century later, Galileo learned to look at the northern lights and mistakenly assumed they were reflections of sunlight in the atmosphere. It would take scientists as far back as the 20th century to understand what causes the aurora borealis, but many mysteries regarding this phenomenon remain.

What causes the northern lights?

The cause of the northern lights begins 94 million miles away with the instability of the Sun’s magnetic field. A coronal mass ejection (CME), a solar flare that blasts billions of tons of superheated plasma into space, could travel through the solar system at over 45 million miles per hour and reach Earth in less than a day.

When these solar particles hit the Earth’s magnetic field, they are accelerated up and down our planet’s magnetic field lines toward the North and South Poles. Along the way, they collide with nitrogen and oxygen atoms in the atmosphere, giving these atoms excess energy and this energy is released in a flash of light.

The characteristic colors of the aurora borealis depend on the types of atoms highlighted. For example, interactions between solar particles and oxygen produce red or green light, while collisions with nitrogen produce green and violet light. Magnetic lines of force influence the pattern of the light show, creating the ripples, pulses, lines, and swirls we associate with the event.

When and where can you see the northern lights?

While solar storms are constant, auroras tend to be more dazzling and more frequent during periods of high solar activity, which occur on a roughly 11-year cycle. In the middle of this cycle, the sun goes through a period of intense activity called the solar maximum; The beginning and end of the cycle are characterized by less activity, known as the solar minimum. Our current cycle started in 2019, meaning 2025 will mark the solar maximum and will be the best time to see the aurora over the largest area of ​​the planet, including areas near the equator.

But the Northern Lights and their southern counterpart known as the Southern Aurora are still visible most nights of the year in what is known as the Aurora Region, an area within 2,500 miles of the pole. In the north, the region includes countries such as Greenland, Finland, Canada, and Russia. The darkest and clearest skies in these places are seen in the spring and fall between 10 pm and 2 am, when the northern lights are usually brightest on moonless nights.

dark side of light

Despite hundreds of years of research, scientists are still unraveling the mysteries of the northern lights. For example, until recently, researchers did not know how plasma from a CME reached such extreme velocities. In a study published in 2021, physicists at the University of California, Los Angeles discovered that they solved the mystery by confirming that powerful waves occurring in the plasma, called Alfvén waves, carry electrons that cause auroras and accelerate them as acceleration. in a video game.

In 2018, NASA launched the Parker Solar Probe, which will come closer to the Sun than any previous spacecraft, helping scientists understand and predict major space weather events such as CMEs. Because these events not only create beautiful light shows, they can also harm the technology on which society depends.

In 1859, a powerful CME caused telegraph systems around the world to malfunction, electrocuting operators and setting telegraph paper on fire. In 1989, a severe solar storm that created a spectacular aurora also cut power out of more than nine hours in Quebec, Canada. Solar storms can pose a hazard to navigation and telecommunications systems and satellites.

Today, the National Oceanic and Atmospheric Administration, along with the United States Air Force, controls the Space Weather Prediction Center, which provides forecasts for aerospace and telecommunications fields. For skywatchers, SWPC also provides a nighttime aurora forecast showing the location and probability of the northern lights. Source