Alexander Calder's mobile technology gets biggest ever retrospective at Tate

The artist who devised moving sculptures that mesmerised Einstein celebrated in exhibition that also includes wire portraits of Josephine Baker and Joan MiroThe largest retrospective of Alexander Calder’s mobiles, slowly changing on every breath of moving air – which so enchanted Albert Einstein that the scientist stood gazing at one for 45 minutes – is coming to Tate Modern this autumn.The term “mobiles” was invented by Marcel Duchamp to describe the creations of his American friend,