Aurorae and solar maximum

Aurorae are one of nature’s most beautiful spectacles, but also one of the most elusive. For aurora hunters, some nights will yield little more than a green smudge on the horizon, others nothing at all. But then will come the nights when the air will burst into life as light dances across the sky.

There are no guarantees when it comes to seeing aurorae, but you might be able to stack the odds in your favour. The next few years are going to be some of the best for those hoping to catch the lights, as our Sun is currently approaching a time of intense activity, known as solar maximum. Scientists watching the Sun predict this could happen in 2024.

To understand why, we must travel to the aurorae’s beginnings on the surface of the Sun. Our star emits a constant stream of charged particles, known as the solar wind, that traverses through the Solar System at huge speeds.

This wind then eventually collides with our planet, or rather the protective bubble created by Earth’s magnetic field around the planet, known as the magnetosphere. Magnetic fields can skew the path of charged particles, changing their motions so that they move along its field lines. As such, the solar wind is deflected around the magnetosphere so that most of it passes safely around the outside, like water flowing past a rock in a stream.

Some of the particles, however, are able to sneak through into our magnetosphere. Once inside, they become caught in field lines that guide them down towards the planet. These solar particles, along with others that were previously trapped within our planet’s radiation belts, are then accelerated down towards the surface by Earth’s magnetic field. Forming a ring around the north and south poles, known as the auroral oval, the particles keep travelling until they hit molecules in Earth’s atmosphere. This transfers some of the accelerated particles’ energy, causing the atmospheric molecules to glow. The altitude and the type of molecules