Green curtains rippling silently across a dark Arctic sky look like pure magic, but the actual science behind them starts 93 million miles away, on the surface of the Sun. Here’s the real chain of events that turns a solar storm into one of the most beautiful sights on Earth.
It Starts With the Sun, Not the Sky
The Sun constantly releases a stream of charged particles called the solar wind, mostly electrons and protons, traveling through space at 400 to 800 kilometers per second. Most of this steady stream gets deflected harmlessly around Earth by our planet’s magnetic field, which acts like an invisible shield. During stronger solar events, coronal mass ejections and solar flares, that stream intensifies dramatically, sending a much larger surge of particles racing toward Earth.
When that energy reaches Earth’s magnetic shield, it doesn’t just bounce off, it gets deposited and accumulated in our magnetosphere, then eventually released, raining down into the upper atmosphere near the poles.
Why the Colors Change
Once those particles funnel down toward Earth’s magnetic poles, they collide with oxygen and nitrogen atoms in the atmosphere, and it’s that collision that actually produces the light, giving the atoms extra energy that gets released as tiny specks of glow, essentially the same basic principle that makes a neon sign light up. Which color appears depends entirely on which gas gets hit and at what altitude.
Green, the most familiar aurora color, comes from oxygen excited around 60 to 120 miles up. Higher still, above 120 miles, oxygen produces red instead. Nitrogen glows blue in that same 60 to 120 mile band, and closer to the ground, below 60 miles, it produces a reddish-pink glow. When several of these processes overlap, the result can shift toward purple, pink, or even white.
The aurora borealis glowing over Ny-Ålesund, Norway. Earth’s magnetic field funnels charged particles from the solar wind toward the poles, where they collide with atmospheric gases to create this display. (Image: NASA/Bin Li)
Not Exclusive to Earth
Auroras aren’t uniquely Earth’s phenomenon either, they show up anywhere a planet has both a magnetic field and an atmosphere. NASA spacecraft have spotted them on Jupiter, Saturn, Mars, and Venus, and Voyager 1 first caught a glimpse of Jupiter’s aurora all the way back in 1979. If you’re curious about the star that powers all of this activity in the first place, our profile of what sort of star the Sun actually is covers the churning, magnetically active object driving every solar storm.
Right Now Is a Genuinely Good Time to Look
Aurora activity isn’t constant, it tracks the Sun’s roughly 11-year cycle of magnetic activity. We’re currently deep into Solar Cycle 25, which has significantly outperformed initial forecasts and delivered a rare double-peak pattern, keeping activity unusually strong well into 2026. That’s been pushing the aurora visible at far lower latitudes than usual, with some geomagnetic storms bringing displays as far south as Texas and Colorado.
For more on aurora science and how to photograph them yourself, check out NASA’s full guide to auroras and their photography tips and tricks.
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