Links Comets A photograph of Comet Hale-Bopp, kindly donated to the Observatory by Thomas Bopp.
Comets can be spectacular objects seen in the night-time sky.
They have been associated by the superstitious with disasters and other notable historical events. Until the 1986 opposition of Halley's comet, the true nature of a comet's nucleus was the subject of argument amongst astronomers. The passage of the Giotto probe close to the nucleus of Comet Halley and the many observations that were carried out worldwide have vastly improved our knowledge of the nature of comets. Because comets can be seen so easily, records of the observation of comets can be traced back over many centuries. It was from a study of the historical observations of several comets that Halley, using Newton's new theory of gravitation, showed that the orbits of several comets around the Sun were almost identical.