In the Dark

It’s almost that time of year again. The Autumnal Equinox (in the Northern hemisphere) took takes place this morning (Saturday 23nd September 2023)  at 7.50am Irish Summer Time (06.50 UT).

Although  the term `equinox’  refers to a situation in which day and night are of equal length, which implies that it’s a day rather than a specific time, the astronomical equinox is more accurately defined by a specific event, i.e. when the plane defined by Earth’s equator passes through the centre of the Sun’s disk (or, if you prefer, when the centre of the Sun passes through the plane defined by Earth’s equator). Day and night are not necessarily exactly equal on the equinox, but they’re the closest they get. From now on days in the Northern hemisphere will be shorter than nights and they’ll get shorter still until the Winter Solstice on 22nd December 2023 at 03.27 Irish Time. I don’t think I’ll be up for that event.

Many people take the autumnal equinox to be the end of summer. There is a saying around these parts, however, that `Summer is Summer to Michaelmas Day’ (September 29th), which is not until next week. I must say, though, though it doesn’t feel particularly summery this morning. Temperatures fell dramatically overnight and were at one point barely above freezing…

This entry was posted on September 23, 2023 at 7:15 am and is filed under The Universe and Stuff with tags Autumnal Equinox. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.