Description: The Hubble Ultra Deep Field as simulated by the Millennium Run Observatory (left) compared to the actual observations taken with the Hubble Space Telescope (right). The RGB images shown are colour-composites of images taken through the filters V (blue), i (green), and z (red). The MRObs image shown was taken from a much larger simulated HUDF field. The images measure about 5 arcmin across on the sky and have a pixel scale of 0.03 arcseconds per pixel.