One evening in early September 1859, 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; it's now known that the flare caused the aurora. The flare was a particularly violent eruption from the sun's surface known as a CME, a coronal mass ejection. 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. This episode examines 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.
