Comets are visitors of the night. They are streaks of frost and dust against the black, seen by the tilted heads of those who look up. Comet C/2006 P1, discovered by astronomer Robert McNaught, broke that contract.
By January 12, 2007, its orbit had swung it perilously close to the sun. The solar furnace vaporized its ices with extraordinary violence, forcing a tail of gas and dust to stream outward for millions of miles. The process, known as sublimation, is common. The result was not. The comet’s nucleus, a dirty snowball perhaps a few miles across, produced a tail of such reflective brilliance that it outshone every star in the sky. It reached an estimated magnitude of -5.5, brighter than Venus at its peak. It became, for a brief period, an object not of the night, but of the day.
To see it, one had to look toward the sun—a dangerous act requiring careful shielding of the eyes, often using the obscured disk of the sun itself behind a building or horizon. Witnesses described a slender, fan-shaped plume of white light hanging in the blue, a ghostly scratch on the dome of the afternoon. It was a reversal of the natural order. The night had invaded the day, not with darkness, but with an excess of light. It asked a quiet question about scale: how something so small, so ephemeral, could command the entire sky, could make the domain of the sun feel shared, if only for a moment.