Friday (Isaac) Newton Blogging: Happy Birthday (for real this time).

January 4, 2008

Dear Isaac,

Happy 364th birthday, old fellow!

I know that folks in England in 1642/3 were a bit distracted. Charles was hardly encouraging a great deal of confidence; there had been that riot at the Archbishop of Canterbury’s palace, and generally folks were on edge. No one much noticed the birth and survival of a tiny baby (small enough, so you later said, to fit into a quart pot) on what the rather backward English still thought was Christmas day, according the Old Style, or Julian Calendar.

But in the more civilized parts of the world — on the Continent, for example — it was well known that the English were a bit backward, and what they believd was only December 25th was actually January 4 in the spiffy, more accurate, new Gregorian Calendar, promulgated by Papal Bull in 1582, but not adopted by the Protestant British until 2/14 September 1752. In that year in Great Britain, September 2 was followed by September 14, and the islanders (and their colonists on the eastern edge of North America) finally brought themselves into agreement with their continental neighbors. (Oddly enough, the British tax year still conforms to the Julian Calendar, beginning on the older system’s New Year in April, not January.)

In any event, Professor Newton, you might be surprised to know that the Gregorian Calendar is now in use pretty much everywhere. It works – and that has ensured its broad acceptance. Its error compared with a true tropical year is slightly less than one day in 3000 years — not at all bad as such calculations go. Given the care you took in making sure all those measurements of tides, the gravitational tugs of the earth at different locations and so on, you’d appreciate the precision with which this kind of thing is being measured these days. We even do leap seconds now, not just days inserted into the calendar every four years.

I must say that I love the irony that the memory of the founder of modern celestial mechanics (the basis for all calendrical calculations) lingers, suspended between the old traditional notions of the year and the new, empirically based demands for calendrical rigor. You yourself were not a Newtonian, of course. You lived between the culture and history that surrounded you, and that which your work reshaped.

December 25? January 4. You celebrated the former. The day that is the actual anniversary of your birth by modern reckoning is the latter. I see no reason not to remember both.

So, once again:

Happy Birthday, Isaac.

Image: William Hogarth, “An Election Entertainment” c. 1755. Hogarth depicts a Whig election carouse. On the floor in the lower right of the image you can see a black sheet — a stolen election poster that reads (you can just make it out) “Give us our Eleven Days” — an anti Gregorian Calender slogan of the opposing Tory party. Source: Wikipedia Commons.