Monday, 6 February 2017

Black hole analog experiment?


This question is directed mostly at people giving lectures on black holes, but input by other physicists or students is very much appreciated.


Do you know a good (home)-experiment with a black hole analog (such as water in a bathtub) that allows to discuss most of the pertinent concepts and features of a black hole?


To clarify what I mean by 'good' let me provide what I consider as a good experiment with a white hole analog (see exercise 2.2 in this exercise sheet), namely a hydraulic jump.


This experiment allows you to discuss in very simple terms what a white hole is (the white hole region is visibly distinct from the exterior because of their different water depths). It is also quite easy to show experimentally that you cannot send information into the white hole (in the form of shallow water wave excitations aka 'ripplons'). Moreover, the white hole exhibits some interesting features in the near horizon region (see the concentric rings in the picture on the back of the exercise sheet). Most importantly, this experiment can be done basically by anyone - there is no need for access to lasers, waveguides, Laval nozzles, supersonic flow etc.


The purpose of the hydraulic jump experiment is to provide a pedagogic introduction to white holes. I would like to have a comparable (non-Gedanken-)experiment available to introduce black holes.




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