An enormous map of the universe has been assembled from the positions of almost 1.3 million quasars; some of these quasars existed just 1.5 billion years after the Big Bang.
By comparing this new map with what's known as the cosmic microwave background (CMB), scientists have been able to roughly verify the distribution and density of matter in the universe, providing more clues as to how large-scale structures in the universe have evolved throughout cosmic history.
