Comets and asteroids: searches and scares Original Research Article

Concern that the Earth might be struck by a comet, with potentially devasting consequences, dates back some two centuries. With the growing appreciation in the twentieth century that asteroidal impacts are also a danger, search programs have been devised in the hope of discovering a specific hazard at least decades, and probably centuries or more, before impact. In describing some of the historical scares, this paper shows an evolution of perceptions of the extent of the threat. It also discusses the development of search programs and procedures. In detailing the particular role of the Minor Planet Center, the paper considers the important legacies, both political and scientific, of the 1997 XF11 scare, as well as what is needed to maintain viable search programs in the twenty-first century.