The autumnal equinox, that is, when we have approximately the same hours of day and night, marks the official beginning of autumn.
As the Earth orbits the sun, in a slightly eccentric orbit inclined at an angle of 23.5 degrees with respect to its orbital path, it changes its orientation with respect to the sun, that is, half the year that the hemisphere North will be pointing towards the Sun and the other half of the Southern Hemisphere will be pointing towards the Sun. Along this orbital path, the Earth will also reach a point of equilibrium where neither of the hemispheres points towards the Sun. This occurs twice a year and is known as the equinox, since the Sun shines directly at the equator of the Earth, so that the length of day and night is roughly the same.
After the official start of the autumn season, as the Earth continues in its orbit, the nights will lengthen and the days will shorten until reaching the longest night of the winter solstice.
Fall is the transitional season between summer and winter, and what we notice the most is the color change in the leaves and the harvest.
The start date of fall varies by climate, tradition, and culture, but when it is fall in the northern hemisphere, it is spring in the southern hemisphere, and vice versa.
In the northern hemisphere, autumn lasts from the autumn equinox (September 22 or 23; in this 2020 we start it on the 22nd) until the winter solstice (December 21 or 22). In the southern hemisphere, fall runs from March to June.
A curiosity: if you travel to Mexico to see the Chichén Itzá monument this day, you will enjoy the descent of the feathered serpent: a famous celebration of the ancient equinox was the Mayan sacrificial ritual of the main pyramid in Chichén Itzá, Mexico. The pyramid, known as El Castillo, has 4 staircases that run from the top to the bottom of the pyramid’s faces, notorious for the bloody human sacrifices that used to take place here. The stairs are built at a carefully calculated angle that makes it look like a huge sun snake is sliding down the stairs on the day of the equinox. Thus, every equinox, in March and in September, and thanks to the calculations of the Mayan architects of the time, the sun casts the shadow of the steps, shaping the serpent; a phenomenon that brings together more than 25,000 people each year.
Do you want to know more curiosities about autumn? Do not miss our gallery.
