Message to the Physics Community, Saturday, March 28, 2020

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Dear Physics Community,

Pretty quiet today, which is good.

I read a new paper on the reverse Janssen effect. The Janssen effect is the support of grain in a silo by the wall of the silo – when you add up the force acting on the base of the sile, F, then mass m=F/g is less than the mass of grain in the silo because the wall of the silo carries some of the weight of the grain, about 10%.  The author of the paper shows that when the filling height is about 15-20 times the grain size, the walls of the silo actually push down on the grain, increasing the force on the bottom.  I suspect knowing this will be useful someday. If you are just starting out in physics, I recommend reading the PRL – it is well written and short.

There was also a good story and animation on how black holes image the entire universe for the Event Horizon Telescope, along with a good animation here.

Vladan Vuletic made a Public Service Announcement about exponentials and epidemics here (file downloads, click to play) which I quite liked.

Physics Department Events

  • Thursday, April 2, 2020, 4-5 pm – Colloquium – Prof. Alan Guth, MIT, “Inflation”
  • April 1-3, Admitted Graduate Studnet Open House, details to come.
  • Thursday, April 2, 2020, 12-1:30 pm – Faculty-Staff-Student lunch, “How we are doing with Remote Teaching So Far?”
  • Thursday, April 9, 2020, 12-1:30 pm – Faculty-Staff-Student lunch, “Social and Ethical Responsibilities of Computing”, David Kaiser and Julie Shah
  • Thursday, April 16, 2020, 12-1:30 pm – “Grading and Exam Guidelines for the Spring Term”, Nergis Mavalvala
  • Thursday, April 23, 2020, 12-1:30 pm – Nikta Fakhri

All events are open to the entire Physics Community.  The zoom link for all lunches is https://mit.zoom.us/j/514440037.

Zoom – as we start remote instruction the day after tomorrow, you may want to watch this zoom tutorial.  It is an hour and pretty basic but has some worthwhile things in it.

Peter

P.S. I am posting these messages in my blog roll here and I have been accumulating useful links that have gone by here. In particular, I am trying to keep a list of MIT policy communications.

Thanks to Physics Council, Cathy Modica, Vicky Metternich and Christina Andujar for input and comments on these messages.