Birkat ha-Hammah (ברכת החמה, also: ha-Chamah, Hahammah, Hachammah), is Hebrew for "The Blessing of the Sun."
It is a special Jewish prayer recited once every twenty-eight years, the period of the solar cycle. Jewish law stipulates that the prayer be said every 10,227 (28 times 365.25) days. The next date set is April 8 2009 (Hebrew year 5769).
According to the Babylonian Talmud (tractate Berachot 59b), at these times the Sun returns to the position that it had when the Universe was first created. The explanation is that if the year would be exactly 365.25 days, the Sun's equinox times would be at the same time in the week every 28 years (28 times 0.25 days equals 7 days). The tradition is that the Sun was created in its Spring equinox position, at the first hour of the night before the fourth day of Creation. Whenever the equinox is thought to occur at that same time of the week, the Sun is said to have returned to its original position.
It is clear that the background of the prayer - the return of the Sun to its original position - is not factual. The assumption that the astronomical year is exactly 365,25 days is incorrect. Nevertheless, the prayer is universally accepted as part of Jewish law on the authority of the Jewish sages.
* 1 Order of the service
* 2 Occurrences
* 3 Lerman's thesis
* 4 Books
* 5 References
* 6 External links
 Order of the service
No set service existed until the Shulkhan Arukh; since then various similar religious services have been offered by Rabbi Moses Sofer, the Mishnah Berurah, and (for Conservative Jews) Lasker and Lasker. The service generally includes:
* Quotations about the sun from the Tanakh
* Four verses from the Tanakh which spell out the Tetragrammaton
* Some of Talmud Berachot 59b
* Parts of Psalms 148 and 90
* The Blessing of the Sun (Barukh Atah...maaseh vereishit)
* Psalms 121, 8 and 19
* The hymm El Adon al kol hama'asim (normally part of the Shabbat services).
* The mourner's kaddish
Occurrences in the last 120 years:
* Wednesday, April 7, 1897
* Wednesday, April 8, 1925
* Wednesday, April 8, 1953
* Wednesday, April 8, 1981
* and will happen on
Wednesday, April 8, 2009
* Wednesday, April 8, 2037
* Wednesday, April 8, 2065
* Wednesday, April 8, 2093
* Wednesday, April 9, 2121
 Lerman's thesis
Moshe Lerman suggested a background to Birkat HaHammah by pointing out a possible connection between the traditional Hebrew dating and the two Mahzorim (cycles) that are observed in Jewish tradition - the "small" 19-year cycle which is the basis of the Jewish calendar, and the "big" 28-year cycle which determines the year in which Birkat HaHammah is recited. Mathematically, if one knows the position of a certain year in both cycles, one can compute the number associated to the year modulo 532 (19 times 28), given that the starting point of both cycles is year 1.
Because the astronomical year is slightly shorter than 365.25 days, the date of Birkat HaHammah shifts away from the Spring equinox as history proceeds. A simple astronomical calculation shows that 84 cycles of 28 years before 5769, in the Jewish year 3417, the Spring equinox was in the beginning of the night before the fourth day of the week as stipulated by the Talmud. Lerman takes this as a hint that the astronomically astute Jewish sages of the time concluded that the Jewish year 3417 was a first year in the cycle of 28 years. Moreover, Lerman suggests that these same Jewish sages would have reasoned that year 3421 was a first year in the 19-year cycle, in accordance with an ancient tradition that the world was created in the first week of the month of Nissan. They would have concluded this from the Spring equinox occurring early in the night leading to the fourth day of the Jewish month of Nissan in the Jewish year 3421.
Lerman surmises that the Jewish sages at the time could argue for a determination of the position of their years in both cycles and could therefore compute the absolute year-count modulo 532 years. They were left with a number of options, 532 years apart from each other, and Lerman suggests that they chose the dating closest to what seemed to be the truth according to a literal interpretation of biblical accounts. The sages legally defined future equinox times by instituting the 28-year cycle, to protect the Hebrew dating against future change, and to leave a remembrance to what they had done.
* Rabbi J. David Bleich. Bircas Hachammah, Blessing of the Sun: Renewal of the Creation: a Halachic Analysis and Anthology. Brooklyn, N.Y.: Mesorah Publications ltd, 1981. ISBN 0-89906-176-1.
* Lasker, AA and Lasker DJ. Birkat Hahammah: The Blessing of the Sun. Conservative Judaism 1981;34:17-28.
* Why Do We Live in the Year 5765? by Moshe Lerman
- theory about the origins of the Hebrew dating
 External links
* http://www.kehillaton.com/en/articles_birkat_hachama.asp [comprehensive discussion on Birkat Hachama]
[downloadable Prayer Service for Birkat Hachama]
The source for birkat ha-chamah is TB Berachot 59b, wherein Abaye said that this berachah is said on the occasion at which the sun returns to its "original position at time of creation." According to Talmudic tradition, the sun was created on Wed., the fourth day of the week, which was also the fourth day of the month Aviv/Nisan. Next year, Wed. Aviv/Nisan 4, 5769 corresponds to Wed. Mar. 29, 2009.