Moth

The other night when Andy and I were walking home from the grocery store, there was a rainbow in a giant arc above us to the east. It was 9:59 p.m. and the western sky was golden-orangey with clouds underlit by the setting sun. The rainbow towered above the nearby hill and seemed to be a mile high. It glowed strangely in the sunset light.

Its reversed twin was visible down at the lower ends of the main rainbow, a little way outside the rainbow itself. This is the rainbow's double, and its colors are reversed in order, with red on the inner side and violet on the outer side. They are usually separated by a dark gap.

But this rainbow was even crazier--inside the rainbow there were echoes of other rainbows hugging the inside tightly without space in between. I've never seen or heard of this phenomenon. Just barely visible, a red band paralleled the inside of the violet band of the main rainbow and the rest of the colors followed, very faintly. Then we could just barely see another red band, even fainter yet, beyond the second violet. The rest was hardly perceptible, but clearly there was something there. It looked like three rainbows piled on top of one another.

The complete arc of the rainbow was also seriously impressive, especially since I've never seen a rainbow at 10:00 p.m. before, and plus, it wasn't even raining! (Well, at least not where we were standing. We did get rained on during the walk home.)

I speculated whether it appeared a thousand feet high. I tried to remember if the skyscrapers in Seattle are 800 feet high or so... I'm not sure. This seemed taller. But of course an estimated height would also imply an estimated distance away, which is hard to tell with rainbows.

But it looked like it was just right over there.

A quick look at Wikipedia's Rainbow entry tells me that we saw a supernumerary rainbow. What's exciting about these is that "it is not possible to explain their existence using classical geometric optics" (wikipedia). Plus, I've never even heard of it before!

And, on an unrelated subject, here's a photo of a moth that was resting on the glass of our newly constructed cold frame that currently houses a young and restless courgette plant (or zucchini for those Americans reading this).