I don't "do daf," but have found your site an excellent source for what I am learning. Your site had the only explanation I could find of why in chutz la'aretz she'elat hageshem begins the night of December 4.
But why did the Rabbis in 1580 not accept the new science and recognize that Shmuel's view (which I assume was based on the Julian calendar) had resulted in beginning 50 days after the Tekufah instead of 60, and that the situation was being cured by adding the 10 days that year only? For that year they should have begun December 1, but for subsequent years, when the Tekufah returned to its proper date, they should have reverted to 60 days after Sept. 23. And now we are only exacerbating the situation by moving further away one day each century (except in those 00 years divisible by 400).
I realize that we give great credence to our predecessors, but was there any dissent, when , as you say, "the Jewish authorities agreed that it was not necessary to institute a parallel change to the Jewish solar calendar with regard to calculating when the Tekufos occur . . . . We still rely on Shmuel's calculation." Has there been any move to challenge this view, which seems clearly wrong?
Your point is well taken. The Tosfos Yom Tov (Kil'ayim 5:5) goes to lengths to prove that we cannot discredit a proven and measurable mathematical fact based on citations from Chazal.
Nevertheless, Chazal have always accepted that the world will not go on forever. According to a famous quote (Rosh Hashanah 31a), it will last up to 6000 years, no more. The Chachamim of the generation that created the Gregorian calendar decided that the amount of drift that will accumulate during the lifetime of this world did not warrant changing the formulae they were using for calculating the length of the solar year. Earlier generations may have been aware of the drift but did not adjust the calendar, they concluded; if so, who are we to take the initiative to do so ourselves.
Moreover, the reason earlier generations of Chachamim did not adjust the calendar was because the formulae used in compiling it were passed down from very early generations. They may even have had their basis in Halachah l'Moshe mi'Sinai (-- this measurement was, after all, part of "Sod ha'Ibur," see Rosh Hashanah 20b). They took this Mesores to mean that the Torah wants us to use this particular length of year for reasons we may not understand, despite the fact that some amount of drift occurs. The Torah foresaw the total amount of drift that will occur until the coming of Moshi'ach, and allowed us -- indeed, advised us -- to practice its Halachos based on such a slightly-off calendar. (A similar argument has been put forward to defend Chazal's measurement of Pi.) If Moshi'ach, when he should arrive, tells us b'Ru'ach Kodsho to change the calendar, of course we shall.
Best wishes,
M. Kornfeld
There is pretty strong evidence that Shmuel himself was aware that the tropical year is shorter than 365 1/4 days.
The Rambam in Hilchos Kidush ha'Chodesh 10:1 quotes an opinion (that of Rav Ada) that the solar year is 4 minutes and somewhat less than 35 seconds shorter than 365 1/4 days. A little further (ibid 10:6) he expresses his opinion that this shorter year was in use by the Beth Din ha'Gadol.
On the other hand, according to Rashi Bava Metzia 85b D"H Shmuel, Shmuel was knowledgeable in 'Sod ha'Ibur'. Consequently, Shmuel knew that at least some components of the calendar are based on a solar year shorter than 365 1/4 days. The Tashbetz in Vol. 1 Siman 108 D"H Teshuva Da'a, writes explicitly that Shmuel knew that the year is shorter than 365 1/4 days (see there a detailed description).
Finally, some ramifications of your correspondent's question/problem are treated in Igros Moshe O"CH Vol. 4 Siman 17 and ibid Vol. 5 Siman 7.
Sincerely,
Mordechai Schwimmer
Brooklyn, NY
Dear Rabbi Kornfeld,
Re the above question, I am sure you are aware that our calendar is not based on the Tekufah of Shmuel, which counts the Solar year as 365 days 6 hr, but uses a more accurate value of 365 days 5 hr 55m 25s (known as Tekufas Rav Ada) which is closer to the 365 day 5hr 48m 46s which is known today. See Rambam, Kidush ha'Chodesh ch.9 sec.1 and ch.10 sec1&6.
I hope this information is of use to you.
Kol Tuv u'Purim Same'ach,
David Sassoon
David,
Your point is well taken; Rav Adda's measurement, upon which the 19 year cycle of leap years is based, is more accurate than that of Shmuel Yarchina'a. (To be more precise, it corrects for the inaccuracy of the Julian/Shmuel calendar about half as much as the Gregorian calendar used today does.)
However, Rav Adda's adjustment is irrelevant to our discussion for one simple reason. It is not used with regard to determining the day upon which we begin to pray for rain! Yes, that is corect: Yiddishkeit is allowing two inconsistent calendars to coexist. Although most of our Halachic calculations are based on Rav Adda's, we start praying for rain (and say Birchas ha'Chamah every 28 years) based on the old, Shmuel/Julian calendar.
As some point out, this allows for the existence of the ridiculous situation in which we will eventually start praying for rain on the first day of Pesach (since we start praying for rain approx. one day later every 250 years)!
As I noted in the original answer, though, this need not bother us, since Mashi'ach will certainly arrive before the 42,000 years that are required for this to happen, and he will certainly institute a new and consistent calendar upon his arrival.
Thank you and l'Hitra'ot,
Mordecai Kornfeld