Auroras uncovered: The advanced science and solar connection
Beyond the beauty lies a complex dance of physics, solar storms, and Earth’s magnetic shield. Here’s how it all works — and how you can read the signs of an incoming aurora.
Northern light from a Waterfront cabin at Skårungen
The Sun–Earth connection
The aurora borealis begins with the Sun’s activity. Our star constantly emits the solar wind — a flow of charged particles, mainly electrons and protons. When the Sun experiences events like coronal mass ejections (CMEs) or solar flares, the amount and speed of these particles can increase dramatically, sometimes reaching Earth in less than 24 hours.
Earth’s magnetic field: The protective shield
Earth’s magnetosphere deflects most of the solar wind, but at the polar regions, the field lines curve down toward the atmosphere. This “magnetic funnel” directs charged particles toward the poles, where they collide with atmospheric gases and produce the aurora.
Earth's magnetic field guiding solar particles to create auroras".
Geomagnetic storms & substorms
Geomagnetic storms occur when strong solar wind streams or CMEs interact with Earth’s magnetosphere, causing a global disturbance that can make auroras visible far from the poles.
Auroral substorms are smaller, localised bursts of activity in the aurora, often causing rapid brightening and movement. These can happen multiple times in a night, sometimes without a major geomagnetic storm.
The Role of the solar cycle
The Sun follows an 11-year cycle of activity, alternating between solar minimum and maximum. During solar maximum, sunspots, flares, and CMEs are more frequent, meaning more opportunities for intense auroras. We are currently approaching Solar Cycle 25’s peak (expected around 2025) — an excellent time for aurora chasers.
Reading the data: Kp-index, Bz, and more
For advanced aurora hunting, real-time space weather data is key:
Kp-index (0–9): Measures global geomagnetic activity. In Lofoten, a Kp of 2–3 is often enough; higher values mean stronger and more widespread displays.
Bz value (north–south component of the interplanetary magnetic field): When Bz is negative, it means the magnetic field is oriented southward, allowing more solar wind to enter Earth’s magnetosphere — a key trigger for auroras.
Solar wind speed: Higher speeds (>500 km/s) can increase auroral activity.
Density: Higher particle density means more collisions and brighter displays.
Why Lofoten has an advantage
Lofoten sits directly under the auroral oval, so even moderate solar activity can produce vivid displays. For photographers, this means you can capture auroras without chasing extreme geomagnetic storms — though those storms can make the experience unforgettable.
Advanced aurora hunting tips
Monitor real-time data from NASA’s DSCOVR satellite or SpaceWeatherLive.
Look for sustained negative Bz combined with high speed and moderate-to-high density.
Be ready for substorms — a quiet sky can suddenly explode in colour within minutes.
In our next Aurora Series post, we’ll explore practical tips for photographing the northern lights — from smartphone shots to professional long exposures.