Artists illustration of the large-scale structure of the universeScience Photo Library/AlamyAstronomers have found the largest known structure in the universe. It is 1.4 billion light years across and contains nearly 70 galactic superclusters. It is also hundreds of thousands of times more massive than a single galaxy, such as the Milky Way.Hans Bhringer at the Max Planck Institute for Physics in Munich, Germany, and his colleagues have named this cosmic structure Quipu after an Incan counting system made from knotted rope. B