Residents of Gongol, Indonesia were left stunned after vibrant “rainbow clouds” lit up the sky in videos that went viral on social media. The unusual clouds displayed swirling bands of pink, green, blue and yellow, leading some viewers to suspect the footage was captured using artificial intelligence.
However, scientists say the phenomenon is quite real and is known as cloud iridescence, a rare optical effect that occurs when sunlight interacts with tiny water droplets or ice crystals inside cirrus clouds. Atmospheric experts say the colorful display highlights how Earth’s atmosphere can sometimes create images that look like they were digitally generated.
What scientists say is cause Rainbow clouds In Indonesia
Scientists explain that cloud iridescence occurs when sunlight is deflected by very small water droplets or tiny ice crystals suspended in clouds.
Diffraction occurs when light bends and scatters after encountering particles similar in size to the wavelength of visible light. This process separates sunlight into multiple colors, creating stunning pastel shades and rainbow-like patterns that can be seen through the clouds.Atmospheric optics researcher Joseph A. Shaw, who has studied iridescence and related sky phenomena, finds that these colors are most clearly formed when cloud particles are unusually small and relatively uniform in size.
According to the researchers, the Indonesian display likely formed under a very specific combination of cirrus clouds, stable weather conditions and the right angle of sunlight.
Why is this phenomenon relatively rare?
Scientists say cloud iridescence does not appear frequently because several weather conditions must coincide at the same time. The clouds should be thin enough for sunlight to pass through, and they should also contain ice drops or crystals that are roughly identical in size.
Even small differences between molecules can weaken colors or prevent the phenomenon from appearing altogether.The researchers also note that the position of the sun and the observer’s viewing angle are extremely important. Newly forming clouds and semi-transparent clouds are more likely to produce vivid iridescence because their particles tend to be more homogeneous.
The difference between rainbow clouds and a real rainbow
Despite their common nickname, rainbow clouds are not technically rainbows.
A classic rainbow is formed when sunlight refracts, reflects and scatters within raindrops after it rains. On the other hand, cloud iridescence is mainly caused by diffraction and interference involving microscopic droplets or ice crystals.Scientists say iridescent clouds usually appear much closer to the sun, and often produce color patterns that are softer and less structured than regular rainbows. Instead of forming a large arc across the sky, the colors are spread unevenly across parts of the cloud.
What clouds can produce iridescence?
Cloud iridescence is commonly seen in altocumulus, altocumulus, cirrocumulus, and lenticular clouds, researchers say. Lenticular clouds are particularly known for their dramatic iridescent displays because their smooth shape and stable airflow often allow very uniform droplets to form.These clouds typically develop at high altitudes where atmospheric conditions remain relatively stable, making it easier for sunlight to constantly interact with suspended particles.
Why do many people believe that videos are created by artificial intelligence?
The Indonesian videos became popular during a period of growing skepticism about widespread visual imagery as AI-generated images became increasingly realistic. Many viewers online wondered if the footage was authentic because the colors appeared unusually vivid and almost digitally enhanced.Scientists say the reaction reflects how the modern public has become more wary of unusual images circulating online.
However, cloud iridescence has been scientifically documented for decades and photographed around the world long before the advent of generative AI.
Similar colorful sky phenomena seen on Earth and Mars
Cloud iridescence belongs to a broader family of atmospheric optical effects that includes horizontal arcs, polar stratospheric clouds, luminous clouds and luminous clouds. All of these phenomena are affected by the interaction of sunlight with water droplets or ice crystals in the atmosphere.Scientists have even observed similar colored cloud phenomena on Mars. NASA missions have imaged bright, iridescent nighttime clouds in the Martian atmosphere, where frozen carbon dioxide molecules can scatter sunlight in unusual ways. Researchers say these displays demonstrate how atmospheric physics can create stunning visual effects on Earth and elsewhere in the solar system.
