2016 Autumnal Equinox marks transition into fall
September 22, 2016 at 9:21 a.m., marked the official start to fall in the northern hemisphere. Every year around September 23rd and March 20th, the Autumnal equinox and Vernal equinox occur. The equinox marks the passage of the sun across the celestial equator and our transition into a new season. The reason why this occurs is due in large part to our earth in relation to the sun. To understand the meaning of equinox, you have to look at the root words, which come from the Italian words aequus and nox meaning equal nights.
Every year, the earth begins a journey around the sun. It’s this journey, in addition to the tilt of the earth at 23.5 degrees, and the rotation that brings about our days, nights, and our seasons. Twice each year, as the sun crosses the equator, it marks the point in time when the northern hemisphere can expect to see shorter days, longer shadows, and colder days. In the southern hemisphere, the exact opposite can be expected. Yes, this means that Australians spend Christmas dashing through the sand.
The transition into cooler weather occurs because the northern hemisphere is starting to tilt away from the sun, while the southern hemisphere is experiencing the opposite, as they are tilting more towards the sun.
The start of fall, among other seasons, is the one point in time when everyone across the globe celebrates it at the same time. This occurs because the earth and sun know no boundaries such as time or place. During this time, we also see the return of an event that only occurs twice each year, that being the sun rising and setting due east and west. This happens because of the position of the sun in relation to the equator.
So before you head in for the evening, look for the sunset at 7:06 p.m. and you’ll know you are looking due west. While those along the equator will see exactly twelve hours of daylight and darkness, here in mid-Missouri, we’ll see 12 hours and 10 minutes of daylight. So, why do we have more than 12 hours? There are two reason we see the extra minutes of daylight, and it’s all due to the sunlight being a disk and not a point, as well as the earth’s atmosphere bending the sun’s rays and giving us the extra daylight. The 12 hours of daylight only occurs when there is a level horizon and no atmospheric refraction, and for us here in mid-Missouri, that will occur this coming Monday, September the 26th. On that day, the sun will rise and set at 7:00. Enjoy the first sunset of fall and know that the cooler weather is coming soon, even though we are still seeing some abnormally warm conditions.
