The Journal Pioneer
Happy New Year!
I hope you had a wonderful Christmas and managed to decompress a little during the holidays. I did; I had a wonderful visit to the family farm. I arrived Saturday, Dec. 22 so my first morning milking was the following day. On my walk back to the house for breakfast after chores, I noticed December’s Full Cold Moon. It was beautifully set in a patch of pastel pink. It took me a moment, but I soon realized I was looking at the elusive Belt of Venus. It’s also known as the anti-twilight arch but that’s not nearly as pretty!
As the sun sets or rises, its light moves through the atmosphere and casts a shadow of the Earth onto the sky. You are, in fact, seeing Earth’s shadow. As the sun rises in the east, the light reflects off the atmosphere to the west, but some of it is blocked by Earth itself. So the lowest part of the atmosphere opposite the sunset is no longer lit up. The Belt of Venus is the thin, yet remarkable pink arch just above the Earth’s shadow at dawn and also at dusk. It’s most visible when the atmosphere is cloudless, just after sunset or before sunrise.
Since the greatest elongation or separation between Venus and the sun is only about 46 degrees, the planet Venus, even when visible, is never located opposite the sun and therefore never found in the Belt of Venus.
So where does the name come from? The name of the phenomenon alludes to the cestus, a girdle worn by the ancient Greek goddess Aphrodite. She is identified with the planet Venus which is named after the Roman goddess Venus.
The next time you’re out to admire or photograph a sunset or a sunrise on a clear day, turn away from the sun and check out what's happening on the opposite side of the sky.