Did ancient supernovae induce proto-humans to walk on two legs, eventually resulting in Homo sapiens with hands free to build cathedrals, design rockets and snap iPhone selfies? A paper published this week in the Journal of Geology makes the case: Supernovae bombarded Earth with cosmic energy starting as many as 8 million years ago, with a peak some 2.6 million years ago, initiating an avalanche of electrons in the lower atmosphere and setting off a chain of events that feasibly ended with bipedal hominins such as Homo habilis, dubbed "handy man." [[{"type":"media","view_mode":"media_original","fid":"60649","attributes":{"alt":"Homo habilis reconstruction in the Museo de la Evolución Humana, Burgos, sculpture by Elisabeth Daynes (2010) based on the KNM-ER 1813 cranium (Koobi Fora, Kenya, dated 1.9 Ma). (CC
