I spotted the rainbow from the beach, as I was walking down the hard-packed sand. I had no phone or camera, just my tiny iPod, so I took a “mind picture” of the fleeting colors.

I tried to memorize the shimmering sight, how it punctuated the beachfront sky with a wan, waning moon above it. The rainbow bathed the morning in vivid light. How surprised I was to see it as I headed south along the shore. How long had it been there?

When I turned around and walked north, I had an even better view, but I knew the colors wouldn’t last. I watched as the rainbow disappeared, thinking about the evanescence of beauty, how it’s our job as humans to enjoy nature’s wonders when we can.

Twenty minutes later, almost home, another rainbow appeared. It rose above the palm trees, scrawled its signature across the sky. And it lasted long enough for me to grab my phone and capture it.