[Avodah] Birkat Hachamah

[Micha Berger]

On Thu, Jan 15, 2009 at 06:43:40PM -0500, Galsaba at aol.com wrote:
: We will say "Birkat Hachamah" , IY"H, on April 8th.
: This is done every 28 years, first counting from Adar 22.
: My question is, why Adar 22?  If Adam was born (to Rav Yehudah) on Friday, 
: Nisan 1, then the Me'orot were created on Wednsday, Adar 29th. Then why do we 
: count from Adar 22?

As RZS mentioned in his post, it's because the day is determined not by
the Hebrew date, but by Tequfas Shemu'el, which will always match the
same Julian Date -- Wed, Mar 26th Julian, which in this century is on
8 April Gregorian.

The idea is that it is when the sun returns to its place, thus the
solar year. It's an approximation, using 365-1/4 days per year. The next
more accurate estimate that we use, Tequfas R' Adda, would make birkhas
hachamah too rare to be meaningful -- every 2,068,417 years. Even rounded
to the nearest cheileq it would be over 907k years. And ANY year to day
ratio is an estimate -- the real number is irrational.

So, we are simply marking when the 365-1/4 day estimate for a year
brings us back to Wed. 365-1/4 days = 52 even weeks, with a remainder
of 1-1/4 days. The 1-1/4 days only add up to an even number of weeks
after 28 years (28 * 1.25 days = 35 days = 5 weeks).

Nothing to do with Hebrew date, except for the Hebrew date of the first
Mar 26 Julian, back at maaseh bereishis.

Tir'u baTov!
-Micha

-- 
Micha Berger             For a mitzvah is a lamp,
micha at aishdas.org        And the Torah, its light.
http://www.aishdas.org                   - based on Mishlei 6:2
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