The faint young sun paradox continues to befuddle scientists. Theory predicts that the early sun should have given off much less heat than it does now, meaning that the young Earth should have been a frozen place, inhospitable place for life. But that’s not what the geological evidence reveals. Fossils of life forms date back to the early days of the Earth, showing that our planet, and hence the sun, were a lot warmer than theory predicts. So how did this happen? Listen in as Philip Mereton discusses this paradox and other mysteries in this sky with Stuart Clark, author of the New Scientist article, Under a Cold Sun, and the book, The Sun Kings.