Have you ever looked up and seen a cloud that looks like it’s been painted in rainbow colours? That’s exactly what people in Indonesia and Yemen spotted earlier this week.
Photos taken in Bogor, Indonesia, and Sana’a, Yemen, showed clouds glowing with bright, swirling colours, almost like a rainbow had merged with the clouds themselves.
The phenomenon is called cloud iridescence, or irisation. It happens when sunlight is diffracted, meaning it scatters as it passes around tiny ice crystals or water droplets inside a cloud. This creates those stunning bands of colour across the sky.
It’s a little different from a regular rainbow. With a normal rainbow, light passes through raindrops. With cloud iridescence, the light bends around the droplets instead, which produces a different kind of effect. Scientists say this doesn’t happen very often. The conditions have to be just right, including newly-formed clouds of certain types, usually spotted around sunrise or sunset. Even when it does occur, the colours are usually quite faint. The vivid photos from this week were especially striking.
Iridescent clouds were also spotted in Malaysia last month, so it has been a busy few weeks for this rare sky event.
