Here in Saskatchewan, we’re no strangers to the stunning green glow of the northern lights dancing across our skies. The vivid green auroras are so common that we often think of them as the signature colour of these natural light shows. But October has brought a change, showcasing a rainbow of colours in the sky—reds, pinks, purples, and blues. So, what causes this kaleidoscope of aurora colours?
While green remains the most frequently observed hue, it isn’t the only colour the northern lights can display. During periods of intense solar activity, other colours emerge, each with a unique scientific explanation.
Reds and pinks, for example, become visible during heightened solar activity. These colours are created when high-energy particles interact with oxygen at extremely high altitudes, with lower oxygen concentrations. Unlike green auroras, which oxygen produces at lower altitudes, the red and pink glow requires intense energy to excite these upper atmospheric particles.
Purples and blues are a bit rarer and are tied to molecular nitrogen reactions rather than oxygen. These vibrant colours occur at lower altitudes, where atomic oxygen is less common. Similar to the reds, blues and purples are also associated with intense solar activity, but they reflect the unique interactions of nitrogen rather than oxygen.
The northern lights we experience here in Saskatchewan are often a visual spectacle of science in motion, and while green is the hallmark of these celestial displays, solar intensity can unlock a vibrant rainbow of colours. So, the next time you look up and see the sky ablaze with colour, you’ll know the science behind the beauty.
No matter the colour, one thing’s certain—Saskatchewan skies never disappoint.