What Are the Northern Lights? Science Explained Simply
Magic night in Alta, Norway!
The Northern Lights are one of those rare things that live up to the hype. They look like magic — glowing curtains of green, pink, and purple rippling across the night sky. But behind the wow-factor is a cocktail of solar physics, Earth’s magnetic field, and a bit of folklore humans have been spinning for centuries.
This guide breaks down what the Northern Lights actually are, how they form, why they come in different colors, and the surprising ways they affect both people and animals — without turning into a boring science lecture. We’ll even talk about the different shapes they take, so you can show off at the next party (providing your friends are nerds like us!)
Want to know everything about the northern lights? Read our complete article: Northern Lights for Dummies.
Spoiler alert: You might have all the information, all the data, all the equipment in the world and perfect weather, but northern lights, as anything in nature, are always unpredictable… and that’s why they’re magical!
What are the northern lights? Quick answer (Aurora for the impatient)
Enjoying the sky’s most amazing phenomenon in the Lofoten Islands, Norway
We briefly covered northern lights science in our exhaustive Aurora Guide, but here is the explanation. Northern Lights, or aurora borealis, are created when charged particles from the Sun slam into Earth’s atmosphere and collide with gases like oxygen and nitrogen. These collisions release energy in the form of light — glowing greens, reds, and purples that shimmer across polar skies.
Or, as NASA puts it: “The aurora is the result of electrons colliding with the upper atmosphere, producing light.”
Want to dive deeper into aurora science? This book is perfect for curious penguins!
Northern lights and tapas?
The Northern Lights aren’t only for the Arctic. During powerful solar storms, people as far south as Spain have reported a faint red or green glow low on the horizon — proof that the aurora can gate-crash even in places better known for tapas than tundra.
This pic is Eli’s very first aurora 18 years ago, and it was outside of the aurora oval (Borlänge, Sweden).
A solar show, powered by the sun
Eli enjoying the show in Alta, Norway
The whole story starts 150 million kilometers away. The Sun isn’t just sitting there shining — it’s a giant nuclear reactor throwing out streams of charged particles called the solar wind.
When the Sun has big eruptions (solar flares, coronal mass ejections), it hurls even more particles into space.
Earth’s magnetic field acts like a shield, funneling these particles toward the poles.
When the particles hit our atmosphere, they excite oxygen and nitrogen atoms — which then release energy as light.
Think of it as cosmic pinball: solar particles slam into Earth’s defenses, bounce around magnetic field lines, and light up our sky (ESA).
Why do the northern lights have different colors?
Grabbed some pink in Luleå, Sweden!
Different gases = different light shows. According to the NOAA Space Weather Prediction Center:
Green (most common): Oxygen at 100–300 km altitude.
Red: Oxygen higher up (above 300 km).
Purple/Violet/Blue: Nitrogen, especially at lower altitudes.
Pink/Yellow mixes: A cocktail of oxygen + nitrogen colliding together.
So if you’re seeing mostly green, you’re not missing out — that’s Earth’s favorite aurora color. Red and purple are rarer, which is why photographers (or we) freak out when they catch them. We’ve seen many green auroras, one blue, and a couple of pink and purple. What a treat!
Not all auroras are born equal
On a windy night in Luleå, Sweden, this aurora started as a shy, still arc and ended up in full blast with showers, curtains and coronas. What a festival!
Auroras don’t all look the same — scientists classify them by shape. You might see them as:
Curtains (classic flowing drapes across the sky — pretty common)
Arcs (long bands stretching horizon to horizon — can be disappointing if they don’t move too much, but they can pick up!)
Coronas (all the lights seeming to explode from a single point overhead — sooo cool)
Pulsating patches (faint flashes that come and go like breathing — the sneaky one)
Showers (rays shooting downward, like green rain — absolutely magical)
Besides the different shapes, they also act differently. Yep, as if they had a mind of their own (we believe they do…) It all comes down to the solar wind. When the flow of charged particles from the Sun is strong and turbulent, the aurora gets restless — twisting, flickering, and racing across the sky like curtains in a storm. When the solar wind is weaker or steadier, the lights can appear calmer, glowing in still arcs that linger for hours. Same phenomenon, just different moods depending on what the Sun is throwing at us.
Penguin Trampoline tip:
Don’t panic if you see “KP 7” and wonder if you need a PhD. The KP index is just a scale (0–9) showing how strong the geomagnetic storm is. The higher the number, the farther south the Northern Lights can appear. In Tromsø, you might catch them at KP 2. In Spain? You’d need a KP 8 or 9 — basically solar fireworks.
And humans aren’t the only ones who notice. In the Arctic, sled dogs often howl under strong auroras, and some researchers suggest they may be sensing the static electricity in the air. Imagine standing in the silence of Lapland, the sky ablaze with green curtains, while a pack of huskies howls in unison — it’s as atmospheric as it gets, and absolute heaven for us.
Northern lights and southern lights
The mountain is on fire in the Lofoten Islands, Norway. Kind of looking like an aurora-erupting volcano!
Northern Hemisphere: Aurora borealis.
Southern Hemisphere: Aurora australis.
Same science, just flipped. The southern version often gets less press because it’s way harder to reach (mostly Antarctica, and Patagonia, Tasmania or southern New Zealand if you’re lucky). The European Space Agency tracks both through satellites — proving that Earth is basically glowing at both ends.
Why are the Southern Lights redder?
Aurora australis often glows with deeper reds and purples because most people watch it from farther away — in Tasmania or New Zealand — where you’re looking at the aurora’s high-altitude “tops” (above 300 km) where oxygen glows red. Add the clear, dark skies over the Southern Ocean, and those rare hues stand out more than in the north.
Pic credits: Arthur Debons
Northern lights folklore: Before science could explain
Eli doesn’t feel the cold. Seriously, if there’s the tiniest possibility of seeing the northern lights, she’ll stay out for hours! Here in Swedish Lapland.
Before we had space weather scientists, people explained the lights in their own way. Think about it, it would have been so scary when you didn’t know where it came from, right?
Vikings thought they were reflections from Valkyries’ armor, guiding warriors to Valhalla.
Sámi people of Lapland believed the aurora had souls and demanded silence and respect — whistling at them was dangerous. Ok, sorry for our aurora playlist!
Finnish legend calls them revontulet (“fox fires”), sparks from an arctic fox’s tail brushing against snowy hills. Pretty!
Inuit tales described them as spirits playing football with a walrus skull. Not so pretty.
In medieval Europe, auroras were sometimes seen as omens of war or plague. Even less pretty.
Science has cleared things up, but the sense of awe hasn’t gone anywhere.
Apps are not magical and didn’t exist in the folklore (although it’s fun to imagine a Viking using an app!), but we do use them to get the best chance at seeing the northern lights. Our pic (Norway) was actually featured in My Aurora App!
Aurora and the solar circle
Auroras aren’t random — they’re tied to the 11-year solar cycle. During solar maximum (when the Sun is most active), geomagnetic storms are more frequent, and auroras can be brighter and visible farther south than usual.
Right now (2025), we’re near Solar Cycle 25’s peak — which means aurora hunters are in for a treat in the coming years. According to NASA, the next few winters could bring the strongest auroras in over a decade. Anyone heading North (if yes, check our Arctic section)? We are!
Northern lights explained: FAQ
Brief aurora in Kemijärvi, Finnish Lapland. Blink and you’ll miss it!
Do the Northern Lights make a sound?
Some people swear they’ve heard faint crackling or rustling, like static. Scientific studies are inconclusive, but Aalto University in Finland recorded low-level sounds during strong auroras. Verdict: rare, but possible.
Why don’t we see aurora everywhere?
Earth’s magnetic field funnels solar particles toward the poles. That’s why auroras cluster in an oval shape around the Arctic and Antarctic, not over the equator (NOAA). For example these are the places to go to see northern lights in Europe.
Do animals react to the Northern Lights?
Yes! Sled dogs have been known to howl under strong auroras, possibly reacting to electrical changes in the air. Locals also say reindeer sometimes stop grazing to look up, as if they know something special is happening.
Can you see them from space?
Yes! Astronauts on the ISS regularly photograph auroras from above — glowing rings of light around Earth’s poles. NASA’s images are jaw-dropping. We also saw them from the plane a couple of times, heading to Churchill, Manitoba and Alta, Norway.
When’s the best time to see the northern lights?
Auroras can show up any time it’s dark, but prime hours are usually between 10 pm and 2 am during aurora season (late September through early April). Want the month-by-month odds — plus tips for dodging cloud cover? Head over to our full guide on the Best Time to See the Northern Lights.
Is travel insurance really necessary for an aurora trip?
Absolutely. The Arctic is gorgeous, but it’s also unpredictable — think whiteouts, icy roads, and reindeer deciding to nap in your path. If you’re planning snowmobile rides or husky safaris, a solid policy is non-negotiable. We use Heymondo, which covers outdoor activities and often runs 5–15% discounts. Grab your discount here.
Got any tips if I want to go see the northern lights?
Yes! Check the aurora forecast before you go, carry spare batteries inside your jacket to keep them warm, and remember that –30°C will drain gear (and you) faster than you expect. For more tricks, we put everything together in our article Northern Lights for Dummies — the ultimate warm-up read before your trip.
Here is our playlist to call the northern lights (although apparently, you’re supposed to stay silent):
The Northern Lights may look supernatural, but they’re a dance between the Sun and Earth — physics at its most beautiful. Whether you call them aurora borealis or australis, they remind us that our planet is alive, connected to the Sun in ways we don’t always see.
So next time you’re standing in the Arctic cold, watching green rivers flow across the sky, remember: you’re seeing the universe in action, and you’re part of a story that started 8 minutes ago on the surface of the Sun.
That said, even with a scientific explanation, they’re nothing short of magical.
Seeing the northern lights is on your bucket list? Explore our dedicated aurora guides:
✨ Northern Lights for Dummies — How to actually see the aurora (without freezing your butt off or waiting 12 nights in vain).
📅 Best Time to See the Northern Lights — Month-by-month, season-by-season, when the sky is most likely to dance.
📸 Northern Lights Photography Tips — Camera settings, tripods, and how not to end up with 200 blurry green smudges.
🌍 Best Places to See the Northern Lights in the World — From Alaska to the Southern lights, the aurora knows no borders (coming soon).
🇪🇺 Best Places to See the Northern Lights in Europe — Iceland, Norway, Lapland and beyond.
🧤 What to Wear for a Northern Lights Trip — Layer up or freeze up: the packing list you actually need at –30°C.
