When Galileo turned his spyglass on the Milky Way he made a marvellous discovery by resolving its misty light into countless stars, distributed in clusters. At a stroke he discovered the vast cosmos that sprawls beyond the solar system. From his survey he decided that the fainter stars were more distant, which was a profound cosmological conclusion in his day. Four centuries later astronomers continue with systematic surveys that are designed to reveal the content and structure of the universe. Two Hot Papers in this period, #2 and #7, bring the latest news on the content of the visible universe.
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