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Why isn't this year divisible by 28?

Why isn't this year divisible by 28?



I understand that the blessing on the sun is to be recited every 28 years in a cycle that begins with the creation of the universe. If so, why is 5769—this years' Jewish year—not divisible by 28?


You are correct, if you divide 5769 by 28 you will be left with a remainder of one. This is because there is no year zero. Rather the world was created in year one. Hence, the cycle was completed for the first time not in year 28, but in year 29. All subsequent cycles are thus divisible by 28 with a remainder of 1.

Incidentally, year zero is not used in the Gregorian calendar, nor was it used in its predecessor, the Julian calendar. Under those systems, the year 1 BCE is followed by 1 CE.

Another point to ponder is the fact that this blessing is intended to mark the day the sun was created. Yet we celebrate the anniversary of all of creation—including the sun—on Rosh Hashanah in the fall.

The explanation is that there is a debate in the Talmud whether the world was completed in Tishrei (the first month of autumn), or in Nissan (the first month of spring). The consensus reached is that it all depends: regarding the counting of years we consider Tishrei to be the beginning of creation, but in areas of Jewish law pertaining to the seasons and astronomy (including the equinoxes), we consider the starting point of creation to be from Nissan (spring). (See "The Chassidic Angle" at the end of this article for an explanation of why this is so.)

The position of the sun, being an astronomical event, therefore relates to Nissan.

Wishing you a happy Passover,

Rabbi Baruch S. Davidson

Rabbi Baruch S. Davidson is a writer who lives with his family in Brooklyn, N.Y.
All names of persons and locations or other identifying features referenced in these questions have been omitted or changed to preserve the anonymity of the questioners.
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Motti.Yarchinai Melbourne, Australia April 20, 2009

Re: the Truth To Ezriel: Don't u understand? U can't prove it from there! It becomes a circular argument. Would u also say the same about Wed? (How do we know the Sun was created on Wed - because Abayye said so)?

Abayye is reporting an already existing 28-yr cycle. There has to be an independent older source for the tradition that the Sun was created at 0hrs just as there is for Wed, else the 28-yr cycle would not have existed in Abayye's day.

If someone had asked Abayye whence do we know the Sun was created on Wed, he would have pointed to Bereshit. What would he have said if asked the same about 0hrs, that we know it because Abayye said it?

So far. NO-ONE has been able to point to any source for such a tradition. BTW, it is not absolutely necessary to assume the Sun was created at 0hrs, just that we wait for it coz it has some special significance for us. Reply

Ezriel Southbend, Indiana April 20, 2009

Re: The Truth The statement of the Talmud on Berachot 59b (and Rashi's commentary) as to what time of day the sun was created should not be so foreign to someone so confident in their knowledge of the details of this topic. Reply

Motti.Yarchinai Melbourne, Australia April 19, 2009

Birkat Hachama - the Truth [Quote: from Baruch Davidson:
" areas of Jewish law pertaining to the seasons and astronomy (including the equinoxes), we consider the starting point of creation to be from Nissan (spring)."

Allow me to correct you sir. The words "and astronomy" were added by you and are incorrect. The new moons are astronomical, and our calendar counts its moladot (mean New Moons), which govern the beginnings of our years & months, from Rosh Hashana. NOT, BTW, the RH of the week of creation, which was RH of year 2 by our count, but RH of the (largely theoretical) year 1, 12 months earlier. (Molad Tohu.)

The tekufot are counted from the Shmuelian March equinox (tekufat Nisan) of year 1 (also a theoretical date, preceding creation by about 6 months), but it was not in Nisan, it was Adar 22 of year 1. (March 26 Julian, year -3759 (3760 BCE).

As a member of the "ask the rabbi" team, can you please cite the source for the notion that the Sun was created at 00:00 on Wed? Not the source for Wed - that is obvious, but where is it stated that this occurred at exactly zero hours (Jewish time) of that day?

Also, on a dozen or more pages on Birkat Hachama on and similar sites, the nonsense claim is repeated over and over that on each occasion of Birkat Hachama (BH) at the exact time of week that the Sun was created, it returns to the position it was in when first created. (This has been thoroughly disproved in my paper "Myths and Maths of the Blessing of the Sun" at:

This was not true either in yr 1 or in any other BH year. Even "The Chassidic Angle" expressly acknowledges that the Sun did not yet exist at tekufat Nisan of yr 1, and tekufat Nisan of yr 2 (the 1st one after the world was created by our year-count) was on Thur (Nisan 3) at 06:00. Why do you keep perpetuating this myth? Reply

Shimon Israel April 16, 2009

World was Ceated in Year 0 and Here's Why As we know, in the year that Noah and his entourage were caged up in the Ark because of the flood, as Rashi points out, the constellations were not in operation. Mind you, this was for 365 days - thus an entire unit of the solar year. Hence, this year is not able to be included in the calculation for the exact positioning of the sun every 28 years, so it has to be that the world was created in the Year 0 - NOT the Year 1. Reply

A. Eisenman Washington, DC April 8, 2009

Why the number 28? I had been hearing about the once in 28 year event of the sun's rising over the horizon and was a little baffled with the number 28. I finally explained to myself why the number is 28. We are celebrating/blessing the moment that the "sun returns to the same position, at the same time of the week" ( The key here is: "same time of the week". Now, please bare with my calculations.

Every year the sun is in the same position that we are interested in, but not on the same day of the week. We'll use the solar calendar as a reference to keep track of the days of the week. Every 4 years that pass, we advance 3 week days. One day every common year, and 2 days on leap years. For example, if 4 years pass, we are 5 week days later. If 8 years pass, we have advanced 10 week days. That is, in the first 10 years we have passed over the 7 weekday later mark which is what we are looking for. So what we want to find is a value for the integer (whole number) k, such that 5k = 7n, for any integer n. Since 7 is a prime number, the first (lowest) k which solves the equation is k = 7. k is the number of 4 year terms which we have to wait. So the answer for the number of years we have to wait is 4 x k = 28.

Now, I'll pose a question:
If we wanted to divide the year into exactly 365 days (and not 365.25, which is the current period around the sun) and 24 hour time periods, the correct way to do it would be to make every second longer by a factor of (365.25)/365. Then if that was the case, the 28 years that we wait would only be 7 years, because each year we would advance one day of the week. So, it seems arbitrary to celebrate it every 28 years since it's just based on the way that we decided to break up time. The right way to do it would have been to stretch a second into a little bit longer period and then at the end of the 365th day of the year, the sun would be in the same spot it (with respect to the earth) was exactly one year ago. In this case we would be celebrating this moment every 7 years. Reply

Anonymous April 4, 2009

why erev pesach? granted that we follow nissan for astronomical events..(and ive forgotten the talmud) but does the talmud give a date for when the world was created in nissan? If it does then why doesnt it always fall out on the eve of pesach i.e. on the same date on the jewish calendar every time the event occurs? Surely if the sun was created on the 4th day of creation, which has a corresponding jewish date, it must always end up at this time! Also I was under the impression that we say that adam was created on rosh hashanah so surely the sun was created only 2 days b4 that? Reply

Zalman Abraham Brooklyn, NY April 3, 2009

Response to Re: are you sure? Even according to the Rambam, if you go back 206 cycles of 28 years, you will arrive at Nissan of the 2nd year, 1 year after the Nissan before creation (i.e. Nissan of Baharad or Shnas Hatohu) that is commemorated in Birkat Hachamah. (Even though it will be the first actual year since creation, it will not be the Nissan of creation (see Eitz Chaim that Nissan of creation PRECEDED Tishrei of creation). Reply

Baruch S. Davidson (author) April 3, 2009

Re: Are you sure? See Rambam, Laws of Shemittah and Yovel 10:2, where he states that the Rosh Hashanah of Adam's creation is called year 2 of Creation. In other words, Shnas Tohu (the "Year of Chaos") which preceded the creation of Adam, from which we calculate the beginning of the moon's cycles in Tishrei and beginning of the sun's cycles in Nissan, is called year 1.

There are alternate ways of calculating the years, which, unlike the Rambam, refer to Shnas Tohu as year zero. They would have to use the "year of the flood" explanation. Reply

Zalman Abraham Brooklyn, NY April 2, 2009

Are you sure? Since this cycle dates back to the Nissan before creation (in Tishrei) it would be dating back to year zero by all accounts! The correct answer is that the year of the flood is not counted since the planets did not move in their orbits during this year, therefore it is not counted when calculating the cycle of the celestial bodies. Reply

Anonymous April 1, 2009

thank you, this is illuminating ;-)
pun delightfullly intended ;-)! Reply

Randy Shoostine Brookline, MA March 31, 2009

Thank you Thank You Rabbi,
Very Interesting Article! Reply

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