Learn — AuroraCast

The aurora — the northern lights (aurora borealis) and their southern twin (aurora australis) — is light given off when charged particles from the Sun, funneled by Earth’s magnetic field, slam into gases high in the atmosphere. Most of the glow happens between about 100 and 300 km up, where oxygen lights up green (around 557 nm) and red, and nitrogen adds blue and purple fringes.

• 🌌How auroras formFrom solar wind to glowing sky — how charged particles, Earth’s magnetic field and atmospheric gases combine to paint the aurora’s colors.
• 📈The Kp index and geomagnetic stormsWhat the 0–9 Kp scale measures, how higher Kp pushes the aurora toward the equator, and how Kp 5+ maps to NOAA’s G1–G5 storm scale.
• ☀️The Sun’s role: solar wind, flares and the solar cycleWhere the energy comes from — sunspots, solar flares, coronal mass ejections, the solar wind and the roughly 11-year cycle that drives aurora seasons.
• 🔭How and when to see the auroraTurning a forecast into a sighting — dark skies, the right direction, the best hours and seasons, and how much warning the forecast gives you.