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Scientists have now found four additional moons orbiting Saturn--bringing the number of satellites around the planet up to 22, the biggest total in our solar system. Brett Gladman, an astronomer at the Observatoire de la Cote d'Azur, first spied two of the new objects in images taken by the European Southern Observatory's 2.2-meter telescope in Chile. A larger telescope in Hawaii then had a look and uncovered the other two. The discovery will be announced at this week's meeting of the American Astronomical Society's Division for Planetary Science.
The new moons are irregular, very small and much farther away from the Saturn than its other 18 moons. [Their relative positions are circled in the image above.] The largest of these tiny orbs, which circle the planet at a distance of some 15 million kilometers, is only 50 kilometers across. The astronomers guess that these new moons--instead of emerging from dust clouds swirling around Saturn--probably got sucked into orbit by the planet's gravitational pull as it cooled and formed. Such an event is more likely in Saturn's neck of the solar system than our own because it is nearer to the asteroid belt. That said, researchers have demonstrated that these new moons are not merely asteroids streaking by the large planet, and they plan to soon discount the remote possibility that the objects are in fact comets.
These four moons are the first irregular moons found around Saturn since the discovery of its only other irregular moon, Phoebe, in 1898. Neighbor Jupiter has nine irregular moons, Uranus fiveand Neptune two. Gladman's group found the irregular satellites around Uranus starting in 1998--and they are still tracking other objects near Saturn. The problem now will be coming up with names for the new heavenly bodies.
