Archives

Categories

Follow My Blog

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Sukkot

/Sukkot

Three-and-a-half Hakafot — Topology of Simchat Torah

Why is this night different from all other nights, asks a child on the Seder night. On this Simchat Torah I asked a different question—why is the day different from the night? Indeed, on the night of Simchat Torah, we dance seven hakafot-circuits. However, during the morning service of the next day, we only dance three-and-a-half hakafot. What is the meaning of this number—three and a half? There are a few instances the Torah, Talmud, and Rabbinic instances where this number is mentioned (e.g., during the Gaonic period, c. 590–1000 CE, in some communities in the Land of Israel, the Torah reading cycle was completed in three and a half years; Maimonides rules that only half of the tzitzit string should be dyed blue leaving three and a half strings white), but none of them [...]

Unified Field Theory… and Practice

Albert Einstein had a lifelong quest—to develop a unified field theory—the theory that would describe as a single field gravity and electromagnetism (just as Maxwell unified electric and magnetic fields in a single electromagnetic field). Alas, Einstein did not succeed in his quest. Today, the goal is even more ambitious—to unify all four known fundamental forces: gravity, electromagnetism, strong and weak forces in a single model, the so-called Theory of Everything. If the hypothetical fifth force will be confirmed, it will also need to be included in the Theory of Everything. While theoretical physicists around the world are busy working our various approaches to such Theory of Everything (which include inter alia string theory, loop quantum gravity, etc.), Jews around the world are practicing this unification during the holiday of Sukkot. During Sukkot, [...]

Shabbat in Numbers

Last week Torah portion, Emor, speaks about prohibition of working on Shabbat. In fact, the Talmud enumerates precisely 39 categories of labor forbidden on Shabbat. But why 39? Rabbi Shimon b’ Rabbi Yossi ben Lakunya (Shabbat 49b) suggests that the number 39 can be derived from the number of times the various forms of the word “melacha” (work) appear in the Torah. Unfortunately, it’s not easy to see how this works out. In his commentary on this passage, Rabbi Hananel ben Hushiel (990-1053) already pointed out that this word appears 61 times in the Torah, not 39! Actually, this word actually appears 63 times! Another Talmudic Rabbi Chanina of Sepphoris derives the number 39 homiletically strenuously computing gematriah of the phrase, “These are the things.” (Shabbat 7:2) The lack of clear source for the [...]