MacDonald, co-author of the new study, says that these otherwise impressive arcs may have been described as ‘feeble’, because to the naked eye they can be dimly lit. But even without modern camera equipment to reveal its cryptic purple incandescence, it was clear that Størmer had been spotting STEVE. As well as being faint, these arcs appeared at just the right time, they were away from the main zone of aurora activity, were east-west oriented, and didn’t appear to be drifting to the south – all matching up with how we see STEVE today.