The Universe from yoWay back before distractions such as cell phones, television and electricity, in fact before written history, ancient sites such as Stonehenge (Britain), Angkor Wat (Cambodia) and Machu Picchu (Peru) all included structures to track the Sun in the sky and keep residents informed as to the date and time of the solstices and spring and fall equinox.
Knowing when the fall equinox occurs is not all that important in modern times, but way back when, people kept careful track for reasons like agriculture, to mark the passage of the seasons, and to pass the time waiting for the internet to come. Today, I could wander about city streets for hours before finding someone who might know.
So, to save time, I looked it up. This year, the fall equinox arrived on September 22nd at 8:21am local time.
While the ancients knew when the year’s two equinoxes and two solstices occurred, and what they meant to the local climate, they had no idea what was actually going on (see ‘internet’).
The word equinox comes from the Latin aequis (equal) and nox (night). At the equinox, as the Sun crosses the imaginary line in the sky above our equator, the Earth’s poles are tilted neither toward nor away from the Sun, making night and day approximately the same length. Oddly enough, equal day and night never occurs on the date of the equinox nor at the equator, but it does at different times and latitudes. Your back yard, at 52 degrees north, gets really close to equal day and night on September 25th.
On the equinox, the Sun is directly overhead at noon if you are on the equator, but regardless of where else in the world you are (other than at the poles), the Sun rises exactly in the east and sets directly in the west on that date. You can set your compass by it.
As the equinox has probably already occurred by the time you read this, this is actually a historic piece. For what’s happening right now, pick a clear evening and find a good view of the south - southwest skies. At 7:30pm, Venus will be setting just south of where the Sun did, Saturn can still be found low in the southwest above the star Antares, with red Mars about 15 degrees (a spread hand width) to the east.
The same distance further east lies Pluto, but we can’t see that, so let’s move on. Neptune and Uranus are also up, and both are binocular objects. With the fall equinox heralding earlier evenings, we’ll see if during the next few months we can’t put those binocs to good use in your back yard spotting something a little further away than those chickadees at the feeder.
