Today is the day. Autumn is finally here. The autumal equinox occurs at 3:18 pm on Tuesday, September 22. The Sun is crossing the celestial equator from the northern half of the sky to the southern half.Perhaps you’ve noticed for the last several days that the sun seems to be rising directly east, or setting directly west. Thanks to the way Salt Lake City streets were laid out 150 years ago, twice a year we have the sun in our eyes if we are driving eastward in the morning and westward in the evening. Day and night are approximately 12 hours long. The word ‘equinox’ means ‘equal night.’ The sun is noticeably lower in the sky at noon.
All of these changes are due to the simple fact that Earth equatorial plane is not in line with its orbital plane. The equator is tilted 23.5 degrees relative to Earth’s orbit. Were it not for this tilt, there would be no seasons. No hot summer nights, no ski season, no fall colors, no spring rebirth.
Thankfully, fall is here. Harvest is in full swing. Temperatures are dropping and the leaves are starting to change color.
In the southern hemisphere, however, seasons are reversed. As the noontime sun is sinking in our sky, it is climbing higher and higher ‘down under.’ Our days are shortening, their days are lengthening. Spring is beginning and light is returning to the south pole.
Whatever your preference in seasons, sports, foods, or outdoor activities, enjoy this day, the changing of the seasons.