Today is the Autumn Equinox
The September or Autumn Equinox occurs when daylight and darkness are an approximate equal duration – in fact, equinox is Latin for ‘equal night.’
The Earth has an axil tilt – it does no sit straight in the solar system. It leans on its axis at a 23.4 degree angle. As a result, the northern and southern hemisphere either point towards or away from the Sun depending on the time of year.
For example, when the northern hemisphere points towards the Sun it is summer here in the UK and when it points away it is winter.
But there are two points in the Earth’s orbit that neither hemisphere directly points towards or away from the Sun, resulting in a nearly equal amount of daylight and darkness. These are called equinoxes (the spring vernal equinox takes place in March).
This year the autumn or September equinox happens at precisely 8.21 GMT on the 23rd of September.
Astronomically, once we pass that point we’re in autumn in the northern hemisphere and heading towards the December or winter solstice.
Where should I look to see signs of the equinox in nature?
The knowledge that summer is gone – and winter is coming – is everywhere now, on the northern half of Earth’s globe.
Kings Road, Formby
Kings Road, Formby
If you live in the Northern Hemisphere, you can easily notice the later dawns and earlier sunsets.
Also notice the arc of the sun across the sky each day. You’ll find it’s shifting toward the south. Birds and butterflies are migrating southward, too, along with the path of the sun.
The shorter days are bringing cooler weather. A chill is in the air. In New York City and other fashionable places, people have stopped wearing white. Creatures of the wild are putting on their winter coats.
Vicarage Road, Formby
All around us, trees and plants are ending this year’s cycle of growth. Perhaps they are responding with glorious autumn leaves, or a last burst of bloom before winter comes.
In the night sky, Fomalhaut – the Autumn Star – is making its way across the heavens each night.