No wonder Carl Sagan loved to smoke weed; you need a little bit of that chronic to appreciate the article. So what they're saying is that, if we forget time and talk only of spatial dimensions, that in the 4th dimension, where our 3D world is essentially a flat "membrane", that a 4D black hole in this 4D world collapsed, and a 3D ripple is created (in the 4D world), and the world we we know is this membrane on top of this 3D ripple that is uniformly expanding with uniform temperature. I wonder if dimensions are additive, ie a 4D object in the 4D world is an 8D object?