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Astronomers at the University of Hawaii have found an outer moon of Jupiter
that has been missing for a quarter of a century. Originally observed for six
days in 1975 and designated S/1975 J1, the moon was lost later that year. Brian
Marsden of the Harvard-Smithsonian Center for Astrophysics noticed similarities
between the object spotted by the Hawaii astronomers, one seen in August by his
colleague Matt Holman and the missing moon. Calculations by Harvard-Smithsonian
confirmed that the 5-kilometre moon has a 129-day orbit that takes it between 6
and 9 million kilometres from Jupiter.