Happy spring, and ‘Happy New Year’

Since last Dec. 21, the sun has been climbing higher and higher in the sky, and daylight hours are increasing. This trend will continue until June 20, the first day of summer. As much as I like longer days, it’s rough on stargazing! It doesn’t get dark enough until very late in the evening. I find myself taking in a little more caffeine the morning after spring star parties.

This season is called “spring” because of green grass, plants and flowers springing out. If George Washington or Ben Franklin were still with us, they would also wish you a “Happy New Year”! Back in the day of our nation’s founders, New Year’s Day coincided with the first day of spring. In fact, up until 1752, the start of spring was also officially New Year’s Day in both England and the American Colonies. Back when Washington had his New Year’s bashes, the flowers were beginning to bloom in his backyard.

Back in colonial times, the first day of spring was celebrated on March 25. England and the colonies were still operating under an old calendar, with roots that dated back to Babylonian times. Most of the Western world, especially the Roman Catholic countries, switched over to the Gregorian calendar in the late 1500s.

That calendar had Jan. 1 as the first day of the year. The Gregorian calendar was actually a correction of the Julian calendar that went back to 46 B.C. in the time of the ancient Greeks. England finally decided in 1752 that it was time to be in sync with the rest of the Western world and adopted the Gregorian calendar. Up until then, English royalty were far too arrogant to adapt with everyone else. You undoubtedly didn’t want to push them too hard — that is, if you valued your life!

Having New Year’s Day on the first day of spring makes sense when you think about it. New life, a fresh start, and the promise of many lovely days to come. So what does all this calendar stuff have to do with stargazing? Not a heck of a lot, but I thought you’d find it interesting, and I wanted to get your attention with the headline.

Many of us have been taught that we have equal daytime and nighttime hours, 12 hours each on the first day of spring. That’s just not true! If you check the almanac for this Saturday, the first day of spring, sunrise in Rochester is at 7:12 a.m., and sunset is at 7:22 p.m. We already have almost 10 more minutes of daytime than nighttime. What’s going on here? How does this happen?

Earth’s atmosphere shell is responsible. When we see the sun near the horizon, its light has to travel through a much thicker layer of air than it does when it’s higher up in the sky. The thicker atmosphere near the horizon bends light so severely that objects seem higher in the sky than they actually are. As crazy as this sounds, the sun may actually be physically just below the horizon, but it will appear above the horizon because of the bending of its light. This is called astronomical refraction.

So when are days and nights equal? The answer is St. Patrick’s Day. Maybe the sun does shine on the Irish!

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul and is author of the book, “Stars, a Month by Month Tour of the Constellations” published by Adventure Publications. Send questions to mikewlynch@comcast.net.

The Rochester Astronomy Club welcomes new members and puts on public star parties. Their website is rochesterskies.org.