Monday, September 18, 2017

Our Earth's Journey Around the Sun

Our Earth’s Journey Around the Sun

My daughter recently sent me a simple five word sentence which she had posted in her blog site at http://guhacaveoftheheart.blogspot.com/. As I read it again and then again I paused and turned from what I was planning to do and lingered in its truth. Her shared sentence was: "Time goes from present to past." In essence we by nature look at something and recall another time and image. She also revealed the source of the words as coming from the Zen Master Dogen of 12th century Japan. https://en.wikipedia.org/wiki/Dōgen .

Earlier in that same day I had been struck by the fact that the shadows created by the morning sun shining on the trees in my back yard had moved dramatically from when I had last paid attention to them, and I clearly remembered that I had watched their repeating patterns through an earlier autumn then through winter, spring and summer. Now they had returned to autumn. I hadn’t been paying any conscious attention to the shadow’s movements but they had, indeed, moved and in my mind the never ending cycle revealed itself again. It was at this point that I realized that physical challenges I had faced in the prior year were finally ready to be put aside and I could return to the past and continue my walkabout with time. Where you are when you are ending or beginning the cycle we call a year makes no difference at all.

During the trying time I had forgotten the uniqueness of the earth’s movement and truthfully didn’t even care but it is some of the obvious and the subtle elements of that movement which I choose to share with you today. Join me on my walkabout and observe our earth’s graceful dance around the sun.

Remember: I choose to not share all I have read and learned on my journey because this is my journey. I will, however, leave a few signposts for you to examine and perhaps find your own discoveries. Two of the signposts were shown above. The rest are shown at the end of my walkabout and perhaps the beginning of yours.

Our earth’s journey around our sun takes 365.24 days. Because it is not exactly 365 days, the year needs to be adjusted every four years from 365 to 366 days. The added day makes it possible for all of the seasons to occur at the same time each year. That adjustment year is called leap year. The added day is called leap day and it has been added to February as its 29th day. Leap day has its pluses when it comes to seasons but there is also a drawback for those people who are born on February 29 because they can experience their calendar birthday only once every four years.

Depending on your age, each and every year is accurately described as gone in the blink of an eye or as taking forever. In fact our earth’s journey is not the stately walk of lovers on a beach. On each of the 365.24 days we travel a fairly accurate 1.598 million miles per day at roughly 18.5 miles per second. We experience a time in our journey when we are closest to the sun and yet it occurs on January 3. It is called the Perihelion. Conversely we find ourselves at the greatest distance from the sun on July 4. That event is called Aphelion. Both events occur about two weeks after our two solstices. Both of these words describing our extremes came to us from ancient Greece. Peri means close and Apo means far. Yes the Greeks also had a name for the sun. It is helos. A solstice also has a most and least time. The Summer or June solstice occurs on June 21/22 and the Winter or December solstice occurs on December 21/22. They arrive six months apart. Their season arrivals reflect the times when the sun reaches its highest or lowest point in the sky at noon, and are marked by the longest and shortest days.

Since there is an existing and observable balance between closest and furthest and longest and shortest it is logical to find that we have two periods when there is a time of sameness. Those periods have been named Equinox. An Equinox is the time or date (twice each year) at which the sun crosses the celestial equator. The celestial equator is defined as the projection into space of the earth's equator; an imaginary circle equidistant from the celestial poles. I can hear you thinking about that sentence because I am not really scientifically or mathematically comfortable with another equator and more poles either. It hurts my head too! Just focus on the time of the year when the days and nights are of equal length, about September 22 and March 20, and you understand an equinox.

All of this predictability is only possible because our earth is tilted. It appears that about 4.5 billion years ago an object about the size of Mars collided with our earth and that collision resulted in a world tilted in its relation to the sun. It is the tilt of the world which make the seasons possible. Not only is the world tilted, it actually wobbles between roughly 21.4 and 24.4 degrees and the extremes of the wobble occur within a roughly 41,000 year cycle. The increase and decrease of the tilt can be shown to set the table for our earths predictable heating and cooling cycles. This cycle theory was proposed by a Serbian named Milutin Milankovitch in 1930.

Together, we experience four seasons, equal days and nights, heat and cold, longer and shorter days and we travel through space at high speeds. In all of this, we remain in place and yet we move and because of an ancient collision we all experience the year we sometimes take for granted. Because the journey repeats itself whether you pay attention to it or not and all observable events come and go on a predictable schedule our journey around the sun together is a dance we all can and should enjoy.

Guideposts:
A guidepost is another name for sign post but I prefer it to be merely a guide and not the end.

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