This episode looks at a solar phenomenon called coronal mass ejection - violent eruptions from the sun's surface - examining just how damaging a CME could be and how astronomers, using two new satellites that will travel closer to the sun than ever before, can better prepare us for its impact. A well-known example of a CME was recorded in 1859, when a spectacular blood-red aurora borealis appeared across America. Earlier that same day, in a leafy garden in the UK, a gentleman astronomer had noted a 'white light flare' on the sun's surface. The two events were linked, and it is now known that the flare caused the aurora. Back then, it was considered an astronomical curiosity, but when it happens again, it will be a different story. For the modern, technological world such a violent solar phenomenon could be devastating.