Principle of Least Action III — History
The spectacle of the universe becomes so much the grander, so much more beautiful, the worthier of its Author, when one knows that a small
September 10, 2023 / 24 Elul 5783
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sephirot
Yom Kippur—The Day of Pure Delight
Yom Kippur means “The Day of Atonement.” Some view it as a frightening day full of regrets of the past and anxiety for the future.
September 15, 2021 / 9 Tishri 5782
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Noah’s Ark—Three Layers of Reality
A light shalt thou make to the ark…with lower, second, and third stories shalt thou make it. (Genesis 6:16) We mentioned in the previous posts
October 28, 2020 / 10 Heshvan 5781
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Salt: The Covenant of the Opposites
And every meal-offering of thine shalt thou season with salt; neither shalt thou suffer the salt of the covenant of thy G‑d to be lacking
March 31, 2020 / 6 Nisan 5780
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The Primacy of the Prime Numbers
And the messengers returned to Jacob, saying: “We came to thy brother Esau, and moreover he cometh to meet thee, and four hundred men with
December 13, 2019 / 15 Kislev 5780
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Sukkot — Bringing Time into Space
Jews have a very strange custom to take four species (Heb. arba’a minim)—a fruit of a citron tree (etrog), a branch of a date palm (lulav), boughs from the myrtle tree (chadassim),
October 18, 2019 / 19 Tishri 5780
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Daughters of Zelophehad
Then drew near the daughters of Zelophehad …. of the families of Manasseh, the son of Joseph; and these are the names of his daughters:
July 28, 2019 / 25 Tammuz 5779
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Relational Space
Meditations on the Maaseh Merkavah – II This post is a sequel to my previous post, “Space – Between Future and Past.” For background information,
June 17, 2019 / 14 Sivan 5779
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Space – Between the Future and the Past
Meditations on the Maaseh Merkavah – I We do science by studying nature. We study physics in a lab, peering into space or working out
June 13, 2019 / 10 Sivan 5779
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Ten Sephirot and Special Relativity
The Special Theory of Relativity, published by Albert Einstein in 1905, was a game changer. It ushered the era of new physics dubbed by some
June 2, 2019 / 28 Iyyar 5779
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The Entangled Tenth
And all the tithe of the herd or the flock, whatsoever passeth under the rod, the tenth shall be holy unto the Lord.” (Leviticus 27:32)
June 2, 2019 / 28 Iyyar 5779
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Fractal Tu B’Shevat
When thou shalt besiege a city a long time, in making war against it to take it, thou shalt not destroy the trees thereof by
January 21, 2019 / 15 Shevat 5779
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The Beard of the Long Face is Found
The previous Lubavitcher Rebbe, the Rebbe Rayatz (a.k.a. the Fridriker Rebbe) told the story about his father, the Rebbe Rashab. Once the brother of Rebbe
August 31, 2018 / 20 Elul 5778
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Breaking Symmetry
And Moses turned, and went down from the mount, with the two tablets of the testimony in his hand; tablets that were written on both
March 4, 2018 / 17 Adar 5778
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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
October 15, 2017 / 25 Tishri 5778
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Five Worlds
Today, Yud Shvat, is the yartzeit (anniversary of passing) of the sixth Lubavitcher Rebbe, Rabbi Yosef Yitzchak Schneersohn, a.k.a. the Rebbe Rayatz, or the Frierdiker
February 6, 2017 / 10 Shevat 5777
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Chayei Sarah – where Kabbalah meets physics
And these are the years of the life of Ishmael: one hundred years and thirty years and seven years (Gen. 25,17) You might say the
November 27, 2016 / 26 Heshvan 5777
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The Fifth Force
Now, therefore, write ye this song for you, and teach thou it the children of Israel.” (Deut. 31:19) The four known fundamental forces are: gravitational
October 11, 2016 / 9 Tishri 5777
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Shabbat in Numbers
Last week Torah portion, Emor, speaks about the prohibition of working on Shabbat. In fact, the Talmud enumerates precisely 39 categories of labor forbidden on
May 22, 2016 / 14 Iyyar 5776
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Jacob’s Sheep: Particles, Fields and Strings, and the Architecture of Reality
Synopsis This essay reads Jacob’s agreement with Laban over the streaked, speckled, and spotted sheep as far more than an odd detail in an ancient
November 20, 2015 / 8 Kislev 5776
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Yom Kippur – Disentangling the Entangled
When G‑d created the first humans, Adam and Eve (Chavah), He created them as one. And G‑d created man in His own image, in the
September 24, 2015 / 11 Tishri 5776
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The End of Days I
In this Torah portion, Vayechi, Jacob, gathers his children to reveal to them “Ketz HaYamim”–“the End of Days.” Rashi explains that Jacob’s intention was to
January 2, 2015 / 11 Tevet 5775
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Joseph and His Brothers
I grew up in Russia and was raised on the metric system based on decimal arithmetic. When we immigrated to the U.S., I had to
December 14, 2014 / 22 Kislev 5775
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Forty Two Journeys to the Answer to the Ultimate Question of Life, the Universe, and Everything
These are the journeys of the children of Israel… (Numbers 33:1) When G-d brought the Jews out from Egypt, He brought them out with the mystery of
July 27, 2014 / 29 Tammuz 5774
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Entangled Sisters
The story of entangled twins is continuing in the Torah portion Vayeitzei (Genesis 28:10–32:3.) Structurally, it is very similar to the story in the previous Torah
November 8, 2013 / 5 Kislev 5774
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Tumah and Taharah
The Hebrew words taharah and tumah, which are the subjects of the Torah portion of Chukat (Numbers 19:1–22:1), are usually translated as ritual purity and
June 19, 2013 / 11 Tammuz 5773
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