Autumn equinox: Interesting facts about the end of summer | September 23 2014
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You may have already noticed the warning signs and the date certainly suggests it, but today is, in astronomy terms, the first day of Autumn as the autumn equinox is upon us. There has been a significant shortening of daylight and a distinct chill in the air after sundown. It is all because the sun's position in the sky is today halfway between its positions on the summer and winter solstices.
On both solstices, the sun is either at its' highest position in the sky(summer solstice) or lowest position(winter solstice). The solstices mark the beginning of Summer and Winter in astronomy terms too so it then follows that the halfway points or equinoxes mark the beginning of Spring and Autumn.
Today, the autumnal equinox occurs meaning that the Earth will experience almost the exact same amount of daylight as it will darkness, approximately 12 hours of each. Also, the sun will rise due East and set due West from all locations in the UK and Northern Hemisphere.
As the Earth spins on its axis, each pole gradually tilts either away from the sun or towards the sun. Currently, it is the North pole's turn to tilt away from the sun and therefore we are heading towards Winter. From now until the winter solstice in December, the sun will continue to rise and set farther and farther south day by day. This also means less daylight hours with approximately 2 minutes getting shaved off each and every day.
While here in the Northern Hemisphere, the sun is sinking day by day, it is the opposite situation in the Southern Hemisphere as they enter Spring today. The days will continue to get longer down there until December when the Earth will once again reverse it's tilt and longer durations of daylight will return to us in the Northern Hemisphere.
So there you have it, the moral of the story is to make the most of the daylight while it is still there for the next few weeks. We will also benefit in the Northern Hemisphere from what is known scientifically as the lag of seasons as it takes a while from the oceans and seas to cool fully after being heated throughout Spring and Summer. This means that in September and early October we can still experience some unseasonably good weather!