Carrington Event

"... It was impossible, on first witnessing an appearance so similar to a sudden conflagration, not to expect a considerable result in the way of alteration of the details of the group in which it occurred; and I was certainly surprised, on referring to the sketch which I had carefully and satisfactorliy (and I may add fortunately) finished before the ocurrence, at finding myself unable to recognise any change whatever as having taken place. The impression left upon me is, that the phenomenon took place at an elevation considerably above and over the great group in which it was seen projected."

"Without warning, two beads of searing white light, bright as forked lightning but rounded rather than jagged and persistent instead of fleeting, appeared over the monstrous sunspot group. Momentarily taken by surprise, Carrington assumed that a ray of sunlight had found its way through the shadow-screen attached to the telescope. He reached out and jiggled the instrument, expecting the errant ray to zip wildly across the image. Instead, it stayed doggedly fixed in its position on the sunspot group. Whatever it was, it was not some stray reflection; it was coming from the Sun itself. As he stared, dumfounded, the two spots of light intensified and became kidney shaped."

"... In the case of the Carrington event of 1859, the most severe coronal mass ejection known to have occurred, the propagation time between the Sun and the Earth, at a speed of 2,300 kilometres per second, was seventeen and a half hours. The way to avert the most serious impacts would be to make adjustments to the operation of the electricity grids before the storm struck (see Space Studies Board 2008, Chapter 7). The necessary actions would have to be taken very quickly and in a coordinated way in order to be effective, so they would have to be carefully planned in advance, preferably in an international context."