What makes the latest discovery, dubbed 2004 GU9, of great interest to astronomers is the remarkable stability of its orbit. It has remained a quasi-satellite of Earth for at least 600 years. Before this phase, the object traveled in a horseshoe-shaped orbit that astronomers have tracked back at least 50,000 years. According to Martin Connors of Athabasca University in Alberta, Canada, 2004 GU9 is the first object in its class to maintain a long stretch of orbital stability. Connors presented his team's study of the object at the 2004 Joint Assembly of the American and Canadian Geophysical Unions, held this week in Montreal, Canada.