Free Astronomy Magazine July-August 2014

36 COSMOLOGY has been possible to faithfully reproduce the “cosmic web” – consisting of filaments of clusters of galaxies – that characterizes our universe on a large scale. On a much smaller scale, instead, it has been possible to recreate the morphological evolution of galaxies. The two aims have however never been pursued with a single simulation, due to the astounding supercomputing power needed to recreate structures up to billions of light-years across with a spatial resolu- tion sufficient to highlight individual gal- axies. It follows that the simulation of a confined space, as can be that occupied by a cluster of galaxies, does not necessarily provide results that can be applied to the whole universe, while a low-resolution sim- ulation on a cosmic scale tell us nothing about the basic structures, namely galaxies and galaxy clusters. Besides these, there is T he efficacy of Illustris in simulating reality is impressive, as shown by the image on these two pages. The left half was ex- tracted from the Hubble eXtreme Deep Field, while