First Day of Fall: The Science Behind It
(WRBL) – It’s that time of year when temperatures drop and pumpkin spice lattes and all things fall. Let’s talk a little bit about the science behind the day he makes this season great.
First, let’s talk about the beginning of autumn.
Fall 2021 begins on Wednesday, September 22nd at 2:20 PM CDT. This is the exact moment when the sun’s rays cross the equator. This happens all over the world at exactly the same time, just in different time zones. The sun moves north to south, heading towards the southern hemisphere as spring begins and eventually prepares for summer.
This is also the day when the sun rises due east and sets due west, mainly for everyone except those who live in the North and South Poles. It is either caused by the sun moving on the celestial equator or is an imaginary line above the real contour lines. If you look up at noon, you can see the sun directly overhead. This only happens during both the spring and autumn equinoxes.
Equal day and night:
Equinox means “equal” and “night” in Latin, so expect nearly 12 hours of day and 12 hours of night. The reason this happens all has to do with the tilt of the Earth. First, we see that the Earth is tilted 23.5 degrees on her own axis. During the summer solstice, the axis tilts toward or away from the Sun. This means a trade-off between the northern and southern hemispheres receiving more direct sunlight and warmth. During the equinox, even the Earth’s tilt and orbit combine to prevent the axis from tilting precisely toward or away from the Sun. So day and night are almost the same, but they can be off by a few minutes.
Where do you go from here:
From her our days are shortened and our nights are long. The loss of daylight continues until the winter solstice. It is the day when the tilt of the axis moves away from the Sun in the northern hemisphere. This marks her shortest day of the year in the southern hemisphere, or the longest day of the year.
The first day of winter is Tuesday, December 21, 2021.