For a man who spends his days pondering the climatic catastrophes and geological disasters that will wipe out large chunks of the human population, this week's guest Prof Bill McGuire of the Benfield UCL Hazard Research Centre is a surprisingly cheery chap. James Randerson and the team discuss his latest book Seven Years to Save the Planet and ask whether it is already too late.
The team also revisits the Large Hadron Collider – the greatest experiment ever built. The LHC switch-on date – 10th September – has finally been announced, but will it live up to the hype. We ask veteran theoretical physicist Prof John Ellis.
Ian Sample, environment correspondent David Adam and BA media fellow Marcus Pearce are also on hand to pick through the week's news, including saving the world's primates, an intriguing chemical find on Mars and the bizarre tale of the woman who cloned her pet pit bull terrier.
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