“If the stars should appear one night in a thousand years, how would men believe and adore; and preserve for many generations the remembrance of the city of God which had been shown! But every night come out these envoys of beauty, and light the universe with their admonishing smile.”
― Ralph Waldo Emerson, Nature and Selected Essays
Sometimes, because I go outside every now and then, I’m interested in the movement of the sun and the moon. When is sunrise? When is sunset? When do I need my lights on my bike?
And, up until Covid, some of us liked to ride our bikes in the Trinity River Bottoms and look at the new moon.
It isn’t unusual, therefore, for me to look at a table of sunrise and sunset times. I was doing that today and discovered and odd fact.
The shortest day of the year is the winter solstice, of course. And that is December 21st, of course. December 21 is NOT the earliest sunset however. Here in Dallas, that occurs, well, about now, December 7… or a few days before and after. The sun sets at 5:20. On the 21st, the sun sets five minutes later.
And the winter solstice is not the latest sunrise, either. Here in Dallas, on the 21st, the sun rises at 7:25. But around January 10, it rises at 7:30. Pretty odd. Even though the 21st is the shortest day (nine hours, fifty nine minutes, thirty seconds here in Dallas) the sunrise and sunset are not symmetrically aligned with that date.
This is because of a discrepancy between our modern-day timekeeping methods and how time is measured using the Sun known as the equation of time.
Odd, yeah. Interesting? Well it is to me.