Soap Bubbles on the Surface of a Liquid: a Playful Universe in 3+1 Dimensions, a Real Universe in 4+1 Dimensions

Very simple experiments based on an analogy between two theories (gravitation and capillarity) allowed us to construct a two dimension space toy-universe composed of the surface of a three-dimensional water tank with floating soap bubbles and bubble clusters.This very simple approach leads to a surprising description of our universe with, in particular, the existence of a fourth dimension inaccessible to us. Such a 4th macroscopic dimension suggests the existence of a huge 4 D tank of heavy fluid (analogous to our 3 D water tank) sitting below our three dimensional universe (which is the surface of the main 4 dimensions universe). Among other consequences:an original interpretation of the event horizon of black holes or a simple answer to the problem of missing dark matter.