(all photographs by J. Gerencher)
Rainbows form by droplets of water both bending and reflecting light. Because a reflection is necessarily involved, the light source (usually the Sun) must be behind the observer.
Rainbow at base of waterfall,
Columbia River Gorge, Washington
Rainbow over reclaimed coal strip mine.
Near Pittsburgh, PA.
Rainbow in deck of stratus clouds beneath airplane.
Summit of Mauna Kea, Hawaii, in background.
Note the telescopes on the mountain summit,
which has an elevation of approximately 13,000 feet.