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Nasa plans to test a new oxygen-making device, developed by K.R Sridhar of the University of Arizona, on Mars. How DNA extracted from teeth is being used to identify the bodies of some of the thousands of "the diappeared", Argentinans who were abducted by the military regime. Jack Welch, the first professor of the Search for Extraterrestrial Intelligence (Seti), talks about a new telescope made up of 500-1,000 small antennae. Linguistics professor Peter Ladefoged talks about what the world's 7,000 distinct languages have – and don't have – in common and what is the future of this diversity.