That’s So Second Millennium

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