The Autumnal Equinox 2019

The Autumnal Equinox (in the Northern hemisphere) took place today (Monday 23rd September 2019) at 8.50am in Ireland.

People sometimes ask me how one can define the `equinox’ so precisely when surely it just refers to a day on which day and night are of equal length, implying that it’s a day not a specific time? The answer is that the equinox is defined by a specific event, the event in question being 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 until the Winter Solstice.

For many people the autumnal equinox is taken to be the end of summer, though there is a saying around these parts that `Summer is Summer to Michaelmas Day’ (which does not happen until September 29th). Nevertheless it is the first day of teaching term and the start of the last round of this years matches in English cricket’s County Championship. The end of the cricket season is the end of summer as far as I’m concerned, though I haven’t seen any matches in person this year.

Over the past week or two the new students have been going through various induction and orientation processes, but their first encounter with actual teaching will be tomorrow. I will be greeting our 94 new first-year Mathematical Physics students at 11am on their first day. I hope I don’t put too many off.  Then I start the fourth-years off on  Astrology and Cosmetics Astrophysics and Cosmology. That is assuming that I take the right notes to the right lectures.

Anyway, I think that’s enough rambling for now. I’ve got to finish getting my notes together for the next few days. Let me end by wishing the new and returning students at Maynooth  all the best for the new academic year. That goes for all students everywhere too! Work hard, and enjoy your studies, but don’t forget to enjoy life on the way!

4 Responses to “The Autumnal Equinox 2019”

  1. “For many people the autumnal equinox is taken to be the end of summer, though there is a saying around these parts that `Summer is Summer to Michaelmas Day’ (which does not happen until September 29th).”

    Meteorologists have summer being between June 1 and 31 August (or 30 August?). Also, one could argue that the solstices and equinoxes should be at the middle of the corresponding season, not at the beginning. Note that Midsummer is celebrated on the first day of summer. Then, as an old folkie, of course I know several traditional songs with lyrics such as: ‘Twas on a summer’s morning all in the month of May. 🙂

    https://mainlynorfolk.info/copperfamily/songs/claudybanks.html

    Like with many folk songs, there are various versions which vary slightly in lyrics and music, relationships to other folk songs, and so on. England has an unbroken tradition of such songs going back hundreds of years.

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