Equinoxes and Solstices Explained #Resources

It’s that time of year again where the leaves begin to fall, the days get shorter, the temperature drops, birds fly south, squirrels hide – are you ready for Autumn?

As you know, one Earth year is split in to four seasons; parts of the year where different amounts of sunlight are received as we orbit around the Sun. Earth has a tilt on its rotational axis of 23.4 degrees, meaning both hemispheres of earth are exposed to different amounts of sunlight, at different points in the year.

An equinox marks the date where both hemispheres receive an equal amount of sunlight, an equal amount of night and day. A solstice marks one hemisphere receiving more sunlight than the other, due to being tilted toward/away from the sun. After the solstice date, this starts to rotate around to the next Equinox, and then the other hemisphere has a solstice too.

Autumn and Spring are both marked by equinoxes, two points in the year where the sun illuminates both the Northern and Southern hemispheres equally. Summer and Winter are marked by solstices, the point that the sun is furthest away from the equator, either giving you more sunlight than the southern hemisphere, or less – Summer and Winter.

Interestingly, astronomers base the start dates of the 4 seasons upon the equinoxes and solstices, whilst others may use the traditional Gregorian calendar which splits the seasons in to three month blocks.

Therefore those who follow the astronomical seasons believe:

Autumn will begin on September 22nd 2017.
Winter will begin on December 21st 2017.
Spring will begin on March 20th 2018.
Summer will begin on June 21st 2018.

And according to those who follow the meteorological seasons believe:

Autumn begins on September 1st 2017.
Winter will begin on December 1st 2017.
Spring will begin on March 1st 2018.
Summer will begin on June 1st 2018.

Here’s an interesting infographic that would make a great resource for teaching:

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