That’s So Second Millennium
Episode 039 - Star of Bethlehem

Episode 039 - Star of Bethlehem

December 24, 2018

In this episode we try to give a little workshop on thinking for yourself about a thorny passage in the Bible, specifically what we are to make of this star that supposedly influenced the Magi (wizards? astrologers?) from "the east" to come to Jerusalem looking for Jesus.

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Episode 036 - Anne Hofmeister on Galactic Rotation, Math, and Glass

Episode 036 - Anne Hofmeister on Galactic Rotation, Math, and Glass

December 3, 2018

The times below are continuations from the last episode. My opening is about 1:30, and then we start with galaxy motions at "26:00".

26:00 Galaxy motions

27:00 Galaxy rotation curves: do not match Keplerian orbits

28:00 Galaxies spin more like records (laggy soft records); mass distribution is nothing like the Solar System

29:00 Hurricanes as a better analogy for galaxies

30:00 Stars in a galaxy move in local organization

32:00 Nebulas

34:00 The opposite extreme: rigid body rotation

35:00 Gravitational attraction between stars creating coherence

36:00 Curiosity that gravity and electrical forces are both inverse square laws

37:00 Poisson's equation

38:00 Summing densities in Poisson's inhomogeneous term is physically meaningless; intensive quantities can't be summed that way

40:00 Gauss' theorem: flux through a surface and quantity within a volume

41:00 Summing is for extensive variables

42:00 Pressure an ambiguous variable

43:00 Future work

44:00 Thermal expansivity: Giauque

45:00 Problems with the glass transition measurements done in the past: need to completely drive out water from the experimental charges

48:00 Wrapup