Are you sitting comfortably? You might want to stand up, because we'll be hearing why, in health terms, sitting is the new smoking! We're also taking a look at the science behind weight loss and why shedding extra pounds is so difficult. Plus news of why colds really do prefer the cold, why most of the world's fossil fuels need to stay in the ground if we're to meet climate change targets, and home from home: how scientists have discovered Earth's twin, deep in outer space...