This very morning of a fairly New Year, I was thinking about Revolutions. This is something we all deal with on a daily, monthly, yearly basis. Well, and there are other revolutions but they are so vast it doesn’t stick in my mind. Let’s start with one of those:
A Cosmic Year is about 230 million Earth Years. Sometimes known as a Galactic Year so if you’re trying to rhyme it with something, there is another option. This is the revolution of our Solar system, around the center of the Milky Way Galaxy. At this point I would probably need to stop to answer a question from my children about what this has to do with a candy bar, to which I would probably explain that this is why you shouldn’t eat them very often.
Some much more relevant revolutions, are as follows:
The Earth’s revolution on its axis = about 24 hours. Defines an Earth Day.
The Moon’s revolution around the Earth = 27.32 days.
And then my personal favorite – The Earth’s revolution around the sun. By the way, these can also be called “orbits”. See above reference to rhyming needs.
This is an elliptical orbit with the sun in not quite the center. So about this time of year, the earth is actually closest to the sun – perihelion. I prefer the aphelion, which is the beginning of July. Sure we’re further from the sun in July, but for other reasons; it is warmer, we have many more daylight hours, there are wild raspberries, and I get birthday presents.
This revolution around the sun takes about 365.242199 days. Even if we round that to the nearest hundredth’s place we still see the need for a leap year every so often. so this is what defines a year. I like it best because in any given year, I have only to keep track of one revolution around the sun. simple.
Back in Ptolemy’s time (and because of him. 2nd century), and until Nicolaus Copernicus’ time (16th century), we thought everything revolved around the Earth (geocentrism). Copernicus presented his heliocentric model and contributed to a scientific revolution. Now, most days we believe the earth and other planets (and I include Pluto in this) revolve around the Sun. It took a little doing for everyone to buy into this and change the models I guess.
As I look at my inner self today, I see Pamcentrism – the occasional tendency to believe everything revolves around me. I have known about this tendency for some time now, but there are times when I regress. So this pilgrim will take some time again, to sort herself out, get back to teaching school (which is both my window to my children’s souls, as well as my mirror to my own), and to ordinary days. Possibly some laundry.