Tuesday, December 28, 2004

Analemma and the Jewish problem

It's late December and the days are growing longer again. So why is sunrise still getting later, making it harder for some to daven Shacharit before leaving for work?

The phenomenon is called the analemma, and you can learn more about it here.

(Hat tip: Rabbi Seth Mandel.)


Soccer Dad said...

My grandfather z"l used to say that the reason we (in Golus) start saying "ten tal u'matar" on Dec 4 (or thereabouts) is because it's the earliest sunset of the year. That is correct. But the shortest day of the year is 2 1/2 weeks later. So if sunset is stable or getting later, sunrise must also be getting later and at a faster pace. ie I've noticed this phenomenon. I just didn't know that it had a name!

Zman Biur said...

Your grandfather's explanation is problematic.

We start saying tal umatar on Dec. 4 because our calendar (for this purpose) has not been adjusted over the centuries. The halacha gives the date as 60 days after Tekufat Tishrei, which should be the autumnal equinox or Sept. 23, giving a start date of Nov. 23 for tal umatar. Calendar creep has shifted this to Dec. 4, so tal umatar only starts at the earliest sunset by coincidence.

Furthermore, the gemara appears to explain the date (equinox + 60) as the start of the rainy season in Babylonia. No mention of sunsets, etc.

For more details, please see here (MS Word file).