Why is it that we can’t get rid of famous myths such as the Loch Ness monster, aliens landing in Arizona and only being able to balance an egg on the first days of spring and autumn?
Almost without fail on the first of spring, otherwise known as the vernal equinox, you’ll see someone on TV break away from reading the teleprompter to attempt to balance an egg on its end. When they finally stand it up, they say, “Look, this really works on the first day of spring!” The truth is that if they tried that on a newscast in July, they would be just as successful, because the vernal equinox has nothing to do with balancing anything. You can pull off that egg trick anytime, with enough patience.
The vernal equinox Monday implies balance since the sun is shining directly over the Earth’s equator and both the northern and southern hemispheres receive the same amount of solar radiation and everyone worldwide has equal amounts of daylight and nighttime.
Guess what? That’s another myth. Certainly it’s true about both hemispheres receiving equal sunlight, but actually days are already longer than nights. Just check the weather page of The Herald and you’ll see that we already have 12 hours and 10 minutes of daylight. Equal day and nights for this latitude were achieved on St. Patrick’s Day.
The Earth’s atmosphere is responsible for this. The sun’s incoming light from 93 million miles away is bent by our shell of atmosphere, something called astronomical refraction. The thicker the atmosphere, the more the sun’s light is bent. Whenever the sun is rising or setting anytime of year, its light has to cut through a lot more of the atmospheric shell than it does when old sol is overhead. The bending of the sunlight is so extreme at the horizon that the sun’s disk will appear above the horizon when it’s actually below it, giving us extra daylight.
From now until the first day of summer, June 21, we’ll get a lot more daylight as the sun shines more directly over our Northern Hemisphere and the sun takes a longer and higher arc across the sky. This week the sun will reach a noontime zenith of 45 degrees above the southern horizon, and by June 21st it’ll rise up to more than 66 degrees above the horizon at lunchtime.
Even though astronomical spring is upon us, we all know that actual springlike weather may be lagging behind. Sooner or later though, we break out of winter weather jail, it greens up, and nature begins anew. In fact, until around the 1750s, England and the American colonies celebrated New Year’s Day on the first day of spring. They were popping champagne corks as flowers were blooming. It kind of make sense to me, with all the new life.
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 Roman Catholic countries, switched over to the Gregorian calendar back in the late 1500s. That calendar had Jan. 1 as the first day of the year. Actually, it was a correction to the Julian calendar that went back to 46 B.C., which also had Jan. 1 as the start of the new year. England finally decided in 1750 that it was time to get in sync with the rest of the western world and adopt the Gregorian calendar.
Happy spring and happy new year?
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and author of the new book “Washington Starwatch,” available at bookstores and on his Web site, www.lynchandthestars.com.
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