The green flash is a rare optical phenomenon that can occur just as the Sun rises or sets. It happens because the Earth’s atmosphere acts like a prism, separating sunlight into different colors. The effect occurs due to:
- Atmospheric refraction splitting sunlight into different wavelengths
- Atmospheric dispersion causing different colors to set at slightly different times
- Green light being the last visible color before blue (which is scattered away)
The best conditions for seeing the green flash include a clear horizon (usually over water), very clean air, and an unobstructed view of the sunset. The phenomenon typically lasts only a second or two, making it a challenging but rewarding sight for observers. Despite its name, the color can actually appear more blue-green than pure green.