What are sun dogs?
After those very hot days, it became much colder again which reminded me of the winter time. I remembered one bright winter morning, where Mika and I were walking through the park.
That day there were no winds to chill us down so our winter gear kept us nice and snug. As we left the shadow of the snow-laden trees, I noticed something strange in the sky. I quickly put on my sunglasses to protect my eyes. Our sun was shining bright through a thin layer of clouds that covered most of the sky, but it was not alone up there, rather, there were two other suns! Our big round sun in the middle, and two bright spots on either side of it. Panicked, a strange thought entered my head and I said it aloud without thinking: “Did we end up on a distant planet with three suns?”
Mika, sensing my panic, looked up concerned and quickly realized what was happening. “Worry not”, said the little fox, “we are still very much in our own solar system and not in Alpha Centauri”. I remembered when I read up on Alpha Centauri, it was the stellar system nearest to us with three stars: one big sun-like star, and two little dwarf stars! Maybe my little fox companion was wrong and we really were teleported there!?
“What you see above you are two sun dogs!”, proceeded the fox. “When I first heard about them, I too was surprised they existed,” he said excitedly only to sour his face and grumble: “mostly I was annoyed this pretty phenomenon wasn’t called a sun fox instead”. He then looked at a nearby dog judgingly, only to be met with a proud smirk from the canine.
“Sun dogs? Our sun has dogs now? Are they dwarf suns like those of Alpha Centauri, or are they light shows in the sky, like the glories you told me about the other day?” I asked.
“The latter”, mumbled Mika after composing himself again. “They too are visible because of the clouds, but this time it’s the ice crystals in the cloud that are causing it, not the liquid droplets”.
“Ice crystals like snowflakes?” I asked.
“Exactly!” Mika said. “These ice crystals are shaped like tiny six-sided dinner plates. And when sunlight passes through them, something magical happens.”
“Like a prism?” I guessed.
“Exactly!” Mika said. “The ice crystals refract the sunlight, just like a prism refracts light into colors. But instead of a glory, they make two bright spots on either side of the sun.”
I looked up again. “I see, is that why the side of each sun dog closest to the sun is red, and the outer side is white?”
“Yup, it is because different colors of light are refracted by different amounts,” Mika explained. “Red is refracted the least, so it’s on the inside. Blue and violet are refracted more, so they’re on the outside, but they’re fainter, so we mostly see red and white.”
“Cool!” I said. “But why don’t I see a full circle of light around the sun, like a rainbow halo?”
“That’s a smart question,” Mika said. “If the ice crystals were tiny and floating in all directions, we would see a full ring called a 22-degree halo. But we don’t. That means something special is happening.”
“Like what?” I asked.
“Three things,” Mika said. “First, the ice crystals are big, like tiny flat plates. Second, they’re all floating flat, like pancakes in the sky. And third… the air up there is very still.”
“Why does that matter?” I asked.
“Because if the air is calm,” Mika said, “the ice crystals can fall slowly and stay flat, like a parachute. And when they’re all facing the same way, they only refract the sunlight to the left and right of the sun, making the sun dogs!”
“So the sun dogs are always exactly 22 degrees away from the sun?” I asked.
“Precisely!” Mika said proudly. “And they’re usually at the same height in the sky as the sun. That’s why they look like they’re standing right beside it.”
I smiled. “So sun dogs aren’t real suns. They’re just sunlight playing tricks with ice crystals.”
“Exactly!” Mika said. “And the best part? You can see them any time there’s a cold, clear day with icy clouds. Just keep your eyes on the sky, and maybe bring your sunglasses!”
As we walked on, caught in our conversation, we ended up by the river. And there she was, the dog from earlier, sitting proudly with the sun dog behind her as a beam of light lit up her smile. She looked genuinely happy that we were still talking about sun dogs, a moment that even Mika would later on admit was very cute.
Text: Alexander Mchedlishvili, Illustration: Patrizia Schoch