(photo by Diana: 2007-09-14 - explore)
Rainbow
We don't see many rainbows from our house because we lack an unobstructed view of the horizon. But following Friday's thunderstorm, this one appeared at almost the exact moment of sunset.
This photo shows a primary rainbow and a much weaker secondary bow. But it also shows a phenomenon that I have never noticed before. The sky between these two bows appears clearer and darker than inside the primary bow or outside the secondary bow. What causes that? Any physicists out there?