10/23/2024 | 10:00 AM
For thousands of years, the northern lights have danced gracefully across our night skies, captivating imaginations and sparking curiosity in all those lucky enough to witness them.
Humans didn’t always know what caused these spectacular displays of colour. Though different cultures had many different theories, one of the most popular beliefs was that the lights represented departed souls of ancestors. It wasn’t until the early 20th century that Norwegian scientist Kristian Birkeland put forward the theory that the light of the aurora was caused by magnetic current flowing through the gases of Earth’s upper atmosphere.
Since then, our understanding of what causes the northern lights has increased significantly, and we now know much more about the science behind the patterns and colours of the aurora. So, if you’re curious about why the northern lights appear in different colours, or want to learn a bit more about how they form, read on to get to know one of the world’s most famous natural wonders.
What are the northern lights?
The northern lights – also known as the aurora borealis – are the vibrant displays we see when charged solar particles collide with the different elements and gases in Earth’s atmosphere, releasing energy in the form of light.
The science behind the northern lights is highly complex, and astronomers are still trying to learn more about what causes the specific shapes and movements of the aurora. However, here’s what we know about how the northern lights are formed:
Our sun continuously emits charged particles from its upper atmosphere – known as solar wind – which is projected out into the solar system at monumental speeds. This solar energy reaches Earth's ionosphere (upper atmosphere), where our planet's magnetic field deflects the charged particles towards the poles. There, the solar particles collide with gases like oxygen and nitrogen in the atmosphere which ‘excites’ the electrons of these elements, causing them to release the extra energy as light. It's this atomic collision that creates the spectacular array of bright colours we see in the night sky. The greater the amount of charged solar particles, the brighter and bolder the display, and the higher the chance of seeing the auroras.
In the northern hemisphere, this natural phenomenon is called the aurora borealis, and in the southern hemisphere, it’s known as the aurora australis (borealis and australis are Latin terms for northern and southern). Though they’re not always visible to the naked eye, auroras are present nearly all the time, taking the form of an oval or ‘halo’ around the Earth’s poles. At the North Pole, the auroral oval spans across several countries, including Iceland, Greenland, northern Scandinavia, Russia, Canada, and Alaska.
Different factors such as the strength of solar activity, weather conditions, and light pollution from other sources like the moon, all affect our ability to see aurora on Earth. Choosing the right time and place to see the lights, as well as knowing what conditions are needed, are very important for maximizing your chances of success.
The timing of the sun’s solar cycles – which are 11-year periods of solar activity – can also play a part in aurora visibility. The years 2024 and 2025 are a period of high solar activity known as a solar maximum, which brings with it a higher chance of spotting the aurora. If you’re considering planning a trip during this time, Iceland is the ideal place to hunt for the lights, with plenty of tours and packages to book onto for the perfect aurora adventure.
So, now we know what causes the aurora, let’s dive into some of the details.
'What is an auroa?' An explainer from NASA
Do you need visuals to help you get the full picture? We like this video from NASA – it's pitched at kids, but it makes scientific concepts like magnetic fields, solar winds, and solar storms easier to understand.
Why are the northern lights different colours?
The northern lights appear in a wide spectrum of colours due to the way that solar energy interacts with different elements in Earth’s atmosphere. You’ve likely seen a very similar process if you’ve ever seen elements heated over a flame in chemistry class. Extra energy causes excited electrons to release light energy of various colours.
Different gases in the atmosphere (oxygen, nitrogen, hydrogen and neon) emit different colours because of their different compositions, and some colours are more detectable to the human eye than others. For this reason, many people use smartphones or cameras to photograph the northern lights and get a more vibrant view of the aurora.
Below, we explore what causes the different colours of the northern lights, as well as how likely you are to see each while observing the aurora borealis in Iceland.
Aurora seen from space
Peering through the window of the SpaceX Dragon Endeavour spacecraft, NASA astronaut Matthew Dominick captured this image of the SpaceX Dragon Freedom spacecraft as vivid green and pink aurora swirled through Earth's atmosphere while the International Space Station soared 273 miles above the Indian Ocean.
Taken on October 7, 2024.
Photo from NASA/Matthew Dominick.
Aurora phases and patterns explained
Whether you’ve witnessed the aurora firsthand or seen photographs of this natural wonder, you’ve probably noticed that the lights can appear in a variety of shapes and patterns. This is because – like any storm – geomagnetic storms go through different phases and can take on many forms.
There are three main phases, or stages, of a typical auroral display: growth, expansion, and recovery. When the conditions are right and solar activity is high, viewers can see all three phases of the display.
The growth phase usually begins in the evening, a couple of hours before the brightest lights appear. This is when you’re likely to see a subtle band of colour appearing in the night sky, which slowly transforms into an arc as the event progresses.
The expansion or active phase is the moment aurora enthusiasts wait for – when the lights suddenly burst into bright colours and large rays, often appearing to dance around the sky. During this stage, the magnetic field dips sharply, leading to the most brilliant and dynamic display of the aurora. The aurora in its most active state usually occurs around midnight.
After the dramatic light show, the aurora enters the recovery phase, when the lights gradually begin to fade and become less active. This typically happens in the early morning, and is your last chance to get a glimpse – or photograph – of the display.
Though the shapes at each stage can be predicted, the northern lights are extremely volatile, and no two displays – or sightings – are the same. The fact that the appearance of the aurora borealis can change so much within the course of a single night makes it all the more mesmerizing, and you'll likely stay out well into the night to enjoy this shapeshifting sight.
Northern lights folklore and mythology
Before we understood the science behind the northern lights, many different cultures had varying beliefs about what the aurora represented. In many civilizations, there were a range of interpretations, and the folklore surrounding the lights is a significant part of Icelandic history.
Spirits of the dead
In multiple cultures, the northern lights are believed to be souls of the departed. According to Icelandic folklore, the lights represent lost souls who have not yet reached their final resting place.
In Norse mythology, it was also believed that the aurora was a colourful bridge – called Bifröst – connecting Earth to the heavens. Those who died in battle were led along the bridge to Valhalla, the resting place for warriors.
In other parts of the world, many Indigenous peoples whistled to call the lights closer in order to whisper messages to their dead.
Arctic fox
The legend of the arctic fox is also a popular myth behind the northern lights – particularly in ancient Finnish culture. They believed that the lights were caused by a fox starting fires by brushing its furry tail along the snow, causing sparks to fly up into the sky. To this day, the phenomenon is called revontulet, which means fox fires.
Many also believed that this interaction between snow and the fox’s tail is why the northern lights were only visible during the winter.
Dancing elves
Elves are a huge part of Icelandic folklore, so it’s unsurprising that Icelanders attributed the lights to elves. The dance of the aurora was believed to be caused by elves and hidden people (huldufólk), who emerged from their homes to celebrate under the bright night skies. Some Icelanders claim that they have heard music and laughter while the aurora is visible, a testament to the idea of the lights as a joyous celebration.
Omens
Across Europe, the lights have long been seen as a harbinger of doom, perhaps because of their red, bloodlike glow. They’ve been described as omens of war in Poland, Germany, Denmark, and Estonia, and among the Sámi peoples of northern Scandinavia, Finland and parts of Russia. Icelandic legends describe the lights as a predictor of an upcoming storm or spell of bad weather.
There are also lots of superstitions around the lights – for example, waving or whistling at the lights was said to bring bad luck, particularly in Norwegian culture. Icelandic folklore states that if a pregnant woman gazes at the northern lights, her child will be born cross-eyed.
However, in Iceland, the aurora was typically seen to be a positive omen overall. They were said to represent good fortune, particularly for those about to embark on a significant life event or period of change. Surprisingly, this applied to pregnant women too – as it was also believed that the lights could help to reduce pain during childbirth, as long as the caveat of looking away was followed!
Where to learn more about the northern lights in Iceland
As well as being one of the best places in the world to hunt for the aurora borealis, Iceland has a whole range of exhibitions and museums where you can find out more about the northern lights.
If you’re staying in Reykjavík, why not check out the epic Áróra Show at the interactive museum known as Perlan? In this immersive experience within Iceland’s only planetarium, you’ll embark on a journey through time to uncover the stories and science behind the northern lights. You can also learn more at Aurora Reykjavík (aka the Northern Lights Center) in the Grandi district of the capital. From folklore and mythology to science and viewing tips, this interactive exhibition is the perfect way to enhance your northern lights experience while staying in Iceland.
Feeling inspired to visit Iceland for the northern lights? Read our tips for planning a trip, and check out our recommendations for when and where to hunt for the aurora. Or, let us do the hard work for you with our ready-made northern lights holiday packages, which include return flights from the UK plus accommodation.
We can’t wait to welcome you to Iceland soon!
Come see the aurora in Iceland
The darker the nights, the brighter the lights!