Thursday, January 24, 2013

Chanukah and Thanksgiving: A Once in Eternity Overlap

I just looked into Thanksgiving and noticed it looks like latkes instead of sweet potatoes this year.

I found this fascinating  -- Chanukah and Thanksgiving: a once in eternity overlap.

This  year features an anomaly for American Jews – The first day of Chanukkah coincides with Thanksgiving, on 11/28/2013. It turns out that it has never happened before...and it will never happen again.

Thanksgiving is set as the fourth Thursday in November, meaning the latest it can be is 11/28. November 28 is also the earliest Chanukah can be.

The Jewish calendar as youmay know repeats on a 19 year cycle and Thanksgiving repeats on a seven year cycle. You would therefore expect them to coincide roughly every 19 x 7 = 133 years. Looking back, this is approximately correct – the last time it would have happened is 1861. However, Thanksgiving was only formally established by President Lincoln in 1863. So, it has never happened before.

Why won't it ever happen again?

The reason I see is because the Jewish calendar is very slowly getting out of sync with the solar calendar, at a rate of 4 days per 1000 years which by the way is not bad for a many centuries old calendar! This means that while presently Chanukah can be as early as 11/28, over the years the calendar will drift forward such that the earliest Chanukkah can be is 11/29. The last time Hanukkah falls on 11/28 is 2146 (which happens to be a Monday). Therefore, I believe  this year, 2013 is the only time Chanukah will ever overlap with Thanksgiving.

Of course, if the Jewish calendar is never modified in any way, then it will slowly move forward through the Gregorian calendar, until it loops all the way back to where it is now. So, Chanukah will again fall on Thursday, 11/ the year 79,811.

So what are the plans?


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