Einstein and quantum theory

I’ve been thinking a hundred times more about quantum problems than about general relativity.

Saint Lucy’s Day: the longest night of the year

In Piacenza, the city where I was born, children receive their presents not for Christmas, but on Saint Lucy’s day (Santa Lucia). They say that Saint Lucy’s Day, the 13th day of December, has the longest night of the year:

“Santa Lucia, la notte più lunga che ci sia.”

This, in a way, makes perfect sense, as the Saint Little Girl needs time to go around, house by house, delivering the presents.

However, everyone knows that the longest night of the year (for the Boreal Hemisphere) is not the one between the 12th the 13th of December, but that between the 21st and the 22nd, aka the Winter Solstice! That’s why I always assumed that such a saying was to be meant as a sort of `poetic license,’ possibly suggested by the rhyming words `Lucia‘ and `sia.’

Today, however, I discovered another interesting, plausible reason for the saying. The discrepancy between Saint Lucy’s day and the Winter Solstice could also be due to the introduction of  the Gregorian calendar, in AD1582, which shifted the calendar back of ten~ish days. And so, everything fits together again: how nice!

Happy Saint Lucy’s Day!

Edit 2014-12-16: Richard Gill on Google+ points out that, as a matter of fact, the current St Lucy’s Day has the earliest (though not the longest) night.