Round and round the sun we go! 67,000 miles an hour on a 585 million mile orbit. Seasons come and go based on our planet's 23 1/2 degree tilt to the plane of its orbit, a tilt occurring when the earth was impacted during the solar system's infancy. The earth spins, turns & rotates from west to east, spinning 365 1/4 times while making one trip around the sun. Whoever figured this out was a genius! Man devised calendars as ways of keeping track of time. Millennia, centuries, decades & years were recorded. If a person lives to be 80, he or she will live 960 months: 29,220 days. Earth always casts a shadow into space, and any particular location continually spins in and out of that shadow, which we call night. Calendars play with words and numbers. There are 12 months because that is how many moon cycles there are in a year. 30 days have September, April, June & November. The other months have 31 except for February, which has 28 except for leap year when it has 29. The extra day is added every fourth year to account for the 1/4 day. Beginning the new year on January 1 is an arbitrary civil event, not an astronomical one. Past civilizations have begun their new years on different dates. We divide our year into 52 weeks. Weeks have 7 days because the ancients counted the sun, moon, & the 5 classical planets: Mercury, Venus, Mars, Jupiter & Saturn. Earth was not thought of as a planet. The planets were associated with gods. Earth's axis, that imaginary line extending from the north pole through the south pole, points in the same direction as Earth goes around the sun. We experience the spring equinox, summer solstice, autumn equinox & winter solstice. Equinox means equal nights. Everywhere on the globe! The sun's arc appears to shift north and south during the period we call a year. It is an illusion, and there are many in astronomy. The sun stays put as we circle it. It is we who are moving, and it is our tilt that makes the sun's arc appear to move north and south in the sky. Calendars go up on our walls and come down. People celebrate birthdays and holidays. They may not mean much but do give us a sense of continuity. Astrology is superstition, not science. Astrologers believe personalities depend on what "sign" the sun is "in" when a person is born. Nonsense! For one thing, the constellations (signs) are illusions. For another, the sun is not "in" constellations. It is only in the direction of stars trillions of miles from us. Thirdly, there are now 13 constellations in the zodiac. Astrology fails to account for Ophiuchus the Serpent-Bearer. The sun, moon & planets appear to stay inside the zodiac because of the flatness of our solar system. All its objects are in the same plane. And that is because the solar system coalesced from a spinning cloud of hydrogen left over when the sun formed. The sun was massive enough for the temperature and pressure at its core to jump-start thermonuclear reactions. Hydrogen fused to create helium and so on. Lighter elements were produced inside stars. Heavier elements were produced when massive stars went supernova. The sun emits energy in the form of light and heat. We are told that of our galaxy's 400 billion stars (suns), 3 quarters of them are red dwarfs. These are "cool stars" that burn slow and last a long time. Barnard's star, our second closest star after the Alpha Centauri system, is a red dwarf M star. The sun, earth & planets are globes, spheres & balls. Globes, spheres & balls are the shapes with the smallest surface areas. If an object has enough mass, it will have enough gravity to pull itself into these shapes. Objects like asteroids and small moons do not have enough mass. Globular clusters have millions of stars and lie outside the plane of the Milky Way. They are very old and remain intact because they are outside the chaos of the Galaxy. Open star clusters lie along the plane of the Milky Way and disperse after a few million years. The Pleiades and the Hyades in Taurus are open clusters. In Greek mythology, these stars were half-sisters, daughters of Atlas. There is nothing easy about astronomy, and I have 20 books on my shelf. I have 60 titles in 2 bibliographies. At 73, I do not get under the night sky like I did as a teenager. That is okay. I have star maps in my head. I have attended several star parties since 1996, and it is always good to hang out with astronomers. I have a plan for going to Greece. It was the ancient Greeks who codified the original 48 constellations, although they were influenced by Mesopotamian poets in the Euphrates Valley. Greek myths and stories have survived because the shenanigans of the Olympian gods and goddesses are still interesting. I learned mythology in high school Latin, then applied it to the night sky after my parents bought me telescopes. I sometimes think astronomy is a waste because it takes me out of the world. Nonetheless, it is real knowledge.
The Great American Eclipse is history, almost like it never happened. In spite of the hype, I would rather see a meteor storm than a solar eclipse. As I write, we are on the verge of a total lunar eclipse. Contrary to what people think, there are more solar eclipses than there are lunar eclipses. The difference is that solar eclipses are seen over very small areas while lunar eclipses can be seen by everyone on the night side of our planet.
Jim Colyer 2019