Aurora October 2024 - visible to the naked eye over the Jodrell Plank Observatory.

 

Aurora Borealis -visible from Latitude 52 degrees North
-Taken with a handheld Canon 600d DSLR in the early hours, October 2024.
Image Credit: Kurt Thrust.

"What causes the aurora ?

• The aurora borealis (also called the northern lights) happens when tiny charged particles from the Sun — mostly electrons and protons — reach Earth.

• The solar wind: The Sun constantly releases a stream of these charged particles, called the solar wind.

• Earth’s magnetic field: Our planet has a magnetic field, shaped a bit like a bar magnet, with field lines curving out from the north and south poles. This field usually shields us from most of the solar wind.

• Particles guided to the poles: Some solar wind particles get caught in Earth’s magnetic field and are funneled down toward the poles along those field lines.

• Collision with the atmosphere: When these particles collide with gases high up in the atmosphere (mostly oxygen and nitrogen), the gases become “excited.” As they calm down, they release light — that glowing curtain of green, red, or purple we call the aurora.

• So, the aurora is basically the Earth’s atmosphere lighting up because of a storm of solar particles guided in by the magnetic field.

Why is it usually only near the Earth's North and South poles?

• The Earth’s magnetic field directs incoming solar particles toward the polar regions. This creates a kind of “auroral oval” — a ring-shaped zone around the magnetic poles where auroras usually appear.

• Most of the time, this oval sits well within the Arctic Circle (for the north), meaning the northern lights are a common sight in places like Norway, Sweden, Finland, Canada, and Alaska.

• Why only rarely in the UK at Latitude 52°N?

• The UK is much farther south than the usual auroral oval. For people at that latitude to see the aurora, something special must happen:

• Solar storms: Occasionally, the Sun produces a particularly powerful burst of particles, such as from a coronal mass ejection (CME).

• Solar storms can cause an expansion of the auroral oval: When such a strong storm reaches Earth, it pushes the auroral oval outward, expanding it farther from the poles. During big storms, it can stretch far enough south that the lights become visible from northern England or even further south.

• That’s why the aurora in the UK is rare — it takes unusually strong solar activity to push the lights down that far.

The Solar Disc captured in white light from the JPO in Summer 2024.
The Sun's Photosphere shows lots of dynamic activity with, sunspots and faculae on display. Image Credit: Kurt Thrust.

Imagine the Sun as a great ball of energy, constantly sending out streams of tiny charged particles, like sparks from a bonfire. This stream is called the solar wind. Most of the time, Earth’s magnetic field shields us from the particles, deflecting them away. But near the north and south poles, the field acts like a funnel, guiding some of them down into our atmosphere.

When the particles finally reach the thin air high above Earth, they crash into atoms of oxygen and nitrogen. Those atoms get “excited” for a moment, then calm down by releasing energy as light. That light is what we see as the aurora.

The color depends on which gas is struck and at what height. Oxygen high up glows a soft red, lower down it shines bright green — the most common color. Nitrogen adds streaks of purple or pink. Together, they paint the sky like nature’s neon sign.

Energised atmospheric Oxygen and Nitrogen atoms releasing photons at differing wavelengths creating the red, green, purple and pink auroral colours.
Credit: Pip Stakkert at the JPO.

The shape of the aurora — those tall shimmering curtains — comes from Earth’s magnetic field lines. Charged particles flow along those invisible lines, lighting them up like glowing threads. And because the solar wind is gusty and Earth’s magnetic field quivers under the strain, the aurora doesn’t sit still. It flickers, ripples, and waves, as though the sky itself were alive and dancing.

The Aurora Borealis dancing over the JPO
- Credit: Anita and George Roberts

Usually, this show stays tucked safely within the Arctic Circle, because that’s where the magnetic funnel is strongest. But when the Sun sends a particularly powerful blast — a storm of particles — the glowing oval around the pole expands. On rare nights, it stretches far enough south that people in the United Kingdom, even at latitude 52° north, can look up and catch the northern lights painting their skies". Professor G.P.T Chat visiting astrophysicist at the Jodrell Plank Observatory.