First Day of Fall: The science behind it


(WRBL/NEWS10) – In 2021, Fall will begin on Wednesday, September 22 at 3:20 p.m. The exact moment the sun’s rays will be over the equator, which happens in the exact time all across the globe, just in different time zones. The sun will move from north to south towards the southern hemisphere as it prepares for the next start of spring and eventually summer. 

The season for cooler temperatures, pumpkin spice lattes, and all things fall. So let’s talk a little bit about the science behind the day that makes this season so great.

How did Sept. 22, become the official first day of fall? And why is it called fall?

Equinox is based on the Latin word aequus, which means equal and night, and you can expect close to 12 hours of daylight with 12 hours of the night. The reason this happens is the way the earth is tilted on its axis at 23.5 degrees. During a solstice, the tilt of the axis will either point towards or away from the sun.

The sun will rise exactly due east and set exactly due west for mainly everyone except for those living at the north and south poles, which occurs due to the sun moving on the celestial equator is an imaginary line above the actual equator. if lookup at noon the sun would appear directly overhead, that only happens in the spring and autumn equinox.

During an equinox, the Earth’s tilt and even orbit combine in a way that the axis doesn’t exactly tilt away from or toward the sun thus the days and nights are somewhat equal but maybe a few minutes off.

The loss of daylight will continue until we head towards the winter solstice, this is the day that the tilt of the axis will be away from the sun in the northern hemisphere. Days will become shorter and our nights will become longer. The northern and southern hemispheres trade-off when they receive the sun’s light and warmth directly.

This will mark the shortest day of the year or the longest day of the year in the southern hemisphere. 

Fall is most commonly used because of leaves that fall from trees at this time of the season which the name came about around the 1500s, according to, the name “autumn,” whose roots date farther back to the 1300s.

The first day of winter will be Tuesday, December 21, 2021.

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