There seems to be lots of evidence that these assumptions hold on the largest scales. But this evidence also suggests that dark matter in particular started forming structures way before the normal matter that you and I are made of. Dark matter is indeed clumpy and does indeed bend space time, causing the apparent bending or "lensing" of light and indeed most of the observed structures in our universe. This gravitational lensing is a big industry in cosmology with many present and forthcoming experiments. However, as scientists we astronomers are accutely aware of the limits of our observations and the effect our assumptions may have on our results. Forcing us to constantly question our practice and methodology, improving the workings of and our confidence in our science. Economists, on the other hand, seem not to question their most fundamental assumptions (or even be aware of them). Wanting to expand their flawed models of marketisation into all walks of life (including it seems astronomy). It was not mathematics that caused the crash it was a sorry bunch of overpaid self interested egoists who refuse to admit that they made any mistakes and insist on bail outs whilst the rest of us have to put up with cuts to our treasured public services! Fabio 26 January, 2011 You and people that think as you do are the reason we might be entering another instance of the Dark Ages. There are so many gems in what you typed that it is very hard