# Terumah

Parshat Terumah, Exodus 25:1-27:19 תְּרוּמָה a.k.a. Trumah

## Vectors, Spins, and Gender

Vectors, Spins, and Gender Speak to the children of Israel, and have them take for Me an offering; from every person whose heart inspires him to generosity, you shall take My offering. (Ex. 25:2) Every physics professor teaching physics 101 to freshmen spends the first lecture teaching vector algebra. Why vectors are so important? Because most quantities in mechanics (a branch of physics dealing with motion and forces) are vectors. A vector is a mathematical object that has a magnitude and a direction. For example, velocity is a vector – it shows not only how fast the object is moving, but also in what direction it is moving (it is different from “speed” which is an average velocity and is just a number). Similarly, acceleration is a vector, force is a vector, angular [...]

## Entangled Cherubs

And thou shalt make two cherubim of gold; of beaten work shalt thou make them, at the two ends of the ark-cover. And make one cherub at the one end, and one cherub at the other end; of one piece with the ark-cover shall ye make the cherubim of the two ends thereof. And the cherubim shall spread out their wings on high, screening the ark-cover with their wings, with their faces one to another; toward the ark-cover shall the faces of the cherubim be. And thou shalt put the ark-cover above upon the ark; and in the ark thou shalt put the testimony that I shall give thee. And there I will meet with thee, and I will speak with thee from above the ark-cover, from between the two cherubim which are [...]

## Global or Local?

And let them make me a Sanctuary that I may dwell among them (Ex. 25:8) In modern physics, there are two paradigms usually expressed as locality and nonlocality.  Theoretical physics was born when Isaac Newton published his Philosophiæ Naturalis Principia Mathematica in 1687, where he formulated his laws of motion and the universal law of gravity.  The law of gravity says that two masses attract each other proportionally to the product of their masses and inversely proportionally to the square of the distance between them. This law said nothing about the nature of the gravitational interaction, it did not explain the mechanism of this attraction at a distance.   Newton was bothered by the question of how one body can act on another body far removed from it with nothing in between, i.e., the notion of “action [...]