What is an equinox and why is Google acknowledging it with a doodle? All you need to knowSep 23 (AZINS) Autumn officially began on September 23 at around 2.54 am when the Sun passed over the Earth’s equator.

Google, too, acknowledged the moment by putting up a doodle for the same. In a blg, Google said, “This year’s seasonal Doodle series protagonist, Quinn, curiously follows the path of a falling leaf, waking up a new friend hidden in the deciduous mound. Surely as the trees begin to turn, many, like Quinn, will find warmth in the company of friends old and new, and fun in the potential of colorful, crunchy leaf piles!”

When the Sun passes over the equator, That means night and day will be almost exactly equal in length, since the earth’s tilt and position in orbit render it parallel with the sun. Just following the equinox, the northern hemisphere will gradually begin to tilt away from the sun’s rays and usher in the cool, crisp autumn weather.

But depending on which part of the world you live in, this could have happened anytime between Saturday, September 22, and Sunday, September 23.

At the equinox, at the equator, the Sun rises directly in the east and sets directly in the west. Before the Southward equinox, the Sun rises and sets more to the north, and afterwards, it rises and sets more to the south. The equinox may be taken to mark the end of summer and the beginning of autumn (autumnal equinox) in the Northern Hemisphere, while marking the end of winter and the start of spring (vernal equinox) in the Southern Hemisphere.