WELCOME TO THE AUTUMNAL EQUINOX
Sunday, September 22, 2013 at 2044 UTC (1644 EDT) we encounter the second equinox of 2013 and one of the four major annual “turning points” in our orbit around the Sun. It’s called the Autumnal Equinox but you have to consider for a moment your location on Earth.
Yes, of course for us in the northern hemisphere the event rings in my personal favorite season of the year; fall. Those located in the southern hemisphere however are seeing a different picture completely as they finally get to leave the cold winter behind and enter into spring.
The Autumnal Equinox is the second day of the year when Earth’s poles are directly vertical in relation to the Sun vs. their usual 23.5 degree “tilt” and the latitudes directly horizontal. Another way of looking at it is this; Twice a year (Today and in the spring) the Sun travels directly in line with the equator thus it is the only two times annually that the Sun rises due east and sets due west. Ultimately, what that means is the days and nights are roughly equal in length but even that isn’t 100% accurate as your location heavily influences that claim. Especially if you are at the north-pole where it means you are entering into six months of night and the south-pole, six months of daylight.
So enjoy your changing of the seasons and do what you can to get out and enjoy all it has to offer!
TimeAndDate article on the Equinox: http://www.timeanddate.com/astronomy/equinox-not-equal.html
EarthSky article on the Autumnal Equinox: http://earthsky.org/astronomy-essentials/everything-you-need-to-know-september-equinox