Life on Earth may have started on Mars, a major science conference has heard.
An element believed to be crucial to the origin of life would only have been available on the surface of the Red Planet, Geochemist Professor Steven Benner claims.
Professor Benner argues that the "seeds" of life probably arrived on Earth in meteorites blasted off Mars by impacts or volcanic eruptions.
He points to the oxidised mineral form of the element molybdenum, thought to be a catalyst that helped organic molecules develop into the first living structures, as evidence of his theory.
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Journalist Steve Hewlett, who shared his experience of battling cancer on BBC Radio 4, has died of the disease at the age of 58.
A long-time diplomat, Churkin had been Russia's permanent representative to the UN since 2006.
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