Comet Churyumov-Gerasimenko

This image shows the orbit of Comet Churyumov-Gerasimenko in aqua. The positions of the comet and planets are shown for February 26, 2004, the planned launch date for the Rosetta mission. Click on image for full size (7K GIF) Windows to the Universe original artwork by Randy Russell.

Comet 67P/Churyumov-Gerasimenko was discovered in 1969 by Klim Churyumov and Svetlana Gerasimenko. The comet orbits the Sun once every 6.57 years. Its orbit brings it closer to the Sun than Mars at the closest point (called "perihelion"), and swings it a bit beyond the orbit of Jupiter at its furthest point from the Sun (called "aphelion").

This comet has an odd history. Before 1840 the comet had an orbit that kept it pretty far from the Sun. In 1840 it got close to Jupiter. The strong gravity of Jupiter changed the comet's orbit, moving it closer to the Sun. Another close approach near Jupiter in 1959 moved the comet even closer in. Since the comet was far from the Sun until recent times, it hasn't melted very much. That means it hasn't changed very much since it was "born" when our Solar System was young. Scientists want to study comets like this because they may help the scientists learn about the early times in the history of our Solar System.

The Rosetta space mission will visit this comet in 2014. The spacecraft includes a lander that will touch down on the surface of the comet's nucleus. Scientists think the nucleus of Comet Churyumov-Gerasimenko is about 3 km wide by 5 km long (about 2 miles by 3 miles).