Winter Solstice Northern Hemisphere
Over the years I lost the detail in his explanation (that lesson took place more than 40 years ago) and each time we reach the winter solstice I berate myself for not looking up the facts and reacquainting myself with the magical story of how nature balances life with seasons.
Today, Tristan Gooley posted The Cloud Compass on his blog which includes a brief explanation of Perihelion (the closest point) and Aphelion (the furthest point). These words triggered the missing details from Major Irwin’s explanation so now I have something to search for in Wikipedia.
Major Irwin did not go in to detail, I was 10, but I do remember on a freezing cold morning doubting we could actually be closer to the sun than in summer. The following abridged text from Wikipedia explains Apsis.
An apsis, plural apsides, is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system. Historically, in geocentric systems, apsides were measured from the center of the Earth.
The point of closest approach (the point at which two bodies are the closest) is called the periapsis or pericentre, peri, around, and kentron. The point of farthest excursion is called the apoapsis, apocentre or apapsis (the latter term, although etymologically more correct, is much less used). A straight line drawn through the periapsis and apoapsis is the line of apsides. This is the major axis of the ellipse, the line through the longest part of the ellipse.
My walks, hikes, rambles, kloofing, backpacking, excursions, treks, and walkabouts return to the starting point making it easy to plan your day.