NewsPhysics

A rainbow photographed over New Jersey has revealed the presence of supernumerary arcs, an atmospheric optical phenomenon less common than primary and secondary rainbows. These additional arcs, appearing as pale, repeating bands of color within the main rainbow, offer insight into the wave nature of light and the complexity of its interaction with water droplets in the atmosphere. The image, highlighted by the Astronomy Picture of the Day (APOD) program, underscores the beauty and underlying physics of everyday meteorological phenomena.

Supernumerary arcs are not a reflection of light like the main rainbows, but rather result from the interference of light waves. When sunlight strikes water droplets, it is refracted and internally reflected. However, because water droplets are not point sources of light but spheres of finite size, the light rays emerging from them can interfere constructively and destructively. This interference produces a pattern of color bands that overlap the primary rainbow, being most visible on its inner side and with colors repeating in a different order than the main spectrum (red, orange, yellow, etc.).

“A rainbow photographed over New Jersey has revealed the presence of supernumerary arcs, an atmospheric optical phenomenon less common than primary and secondary rainbows.”