It came from outer space … and went back there two weeks later, having astonished and excited astronomers and planetary scientists.
A cigar-shaped object, less than half a kilometre long and barely bright enough to be detected by the world’s most powerful telescopes, paid us a flying visit in October this year – reminding us that the heavens still hold plenty of surprises.
There have been amazing changes in the way we view the smaller bodies in the solar system over the last five years. The Rosetta spacecraft’s observations of the duck-shaped comet 67P Churyumov-Gerasimenko taught us a lot. Similarly, the heart-shaped ice-covered plains of Pluto photographed by New Horizons and the bright spots on Ceres, as imaged by the Dawn mission, have forced us to revise our ideas of the formation and evolution of comets, asteroids and faraway dwarf planets – and the relationship between them.