The mighty planet Jupiter has 63 official moons, but it turns out there’s always room for more. Researchers used computer models to map the past trajectory of the comet 147P/Kushida-Muramatsu, and determined that for about 12 years it circled Jupiter as a temporary moon. At the ongoing European Planetary Science Congress, astronomers declared that the comet completed two complete orbits of the gas giant, and remained in orbit from 1949 to 1961.
The 1,300-foot-wide comet had a happier fate than other comets that got too close to Jupiter, and were dragged all the way in for a crash landing. Only one temporary satellite has been observed falling prey to a planet’s pull: comet Shoemaker-Levy 9, which broke apart and crashed into Jupiter in 1994…. Unlike [Shoemaker-Levy], comet Kushida-Muramatsu eventually escaped Jupiter’s gravity. It currently circles the sun in the solar system’s asteroid belt, between the orbits of Mars and Jupiter [National Geographic News].
This past July an amateur astronomer gazing at Jupiter from his backyard telescope noticed a “scar” on the planet left by a mysterious impact, which may have been caused by yet another comet caught by Jupiter. Along with the impact of Shoemaker-Levy 9, this illustrates Jupiter’s capacity for sweeping up space debris, protecting Earth from the risk of bombardment But Kushida-Muramatsu’s escape suggests that the giant planet can sometimes have a more delicate touch with its companions, helping them move into the inner solar system [New Scientist].
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Image: NASA. Jupiter and five of its moons.