Monday, 14 September 2009

Jupiter Had Temporary Moon for 12 Years

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JupiterStanding outside on a clear night, people all over the world look up and see a sight familiar throughout the generations of mankind: the waxing and waning of the moon. Our moon has become a symbol of permanence; changes in its appearance, and the regularity of events such as solar and lunar eclipses can be accurately predicted for generations to come. But such seeming-constancy is not the case for every moon.

 According to an Agence France-Presse report, Jupiter had a temporary moon that orbited the largest planet in our solar system for 12 years.

 

Data presented at the European Planetary Science Congress in Potsdam, near Berlin, showed that the biggest planet of the Solar System gained a temporary satellite, a comet called 147P/Kushida-Muramatsu, between 1949 and 1961.

 

It is only the fifth captured comet to be identified, a press release said....

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Kushida-Muramatsu, though, completed two full revolutions of Jupiter, following an irregular orbit, before it gained its freedom, according to calculations led Katsuhito Ohtsuka of the Tokyo Meteor Network.

 

"The results of our study suggests that impacts on Jupiter and temporary satellite capture events may happen more frequently than we previously expected," said David Asher of Northern Ireland's Armagh Observatory, who presented the data in Potsdam.

 

When Shoemaker-Levy 9 was torn apart by Jupiter in 1994, images of the comet’s fragments striking the planet captured scientific and popular attention around the world. Today, Jupiter’s tremendous gravitational forces hold 63 moons in orbit around the gas giant and, scientists are concluding with greater certainty, the planet exerts a tremendous influence on comets, and thus influences the destiny of every planet in the inner solar system — including Earth.

 

Both Shoemaker-Levy 9 and 147P/Kushida-Muramatsu demonstrate a crucial role for Jupiter in shaping the course and life expectancy of comets. As David Asher is quoted at UniverseToday.com: “Fortunately for us Jupiter, as the most massive planet with the greatest gravity, sucks objects towards it more readily than other planets and we expect to observe large impacts there more often than on Earth. Comet Kushida-Muramatsu has escaped from the giant planet and will avoid the fate of Shoemaker-Levy 9 for the foreseeable future.”

 

One result of Jupiter’s role as the gravitational heavyweight among the planets is that it it protects Earth from comets that otherwise might strike our world — chalk up the presence of a world such as Jupiter in our outer solar system as one more providential circumstance that makes life on Earth possible: Jupiter is far enough away from Earth to keep it from interfering with our own orbit, but it is near enough to greatly reduce the threat of unthinkable destruction a collision with a comet would mean for Earth.

 

The team that discovered Jupiter’s temporary planet has made a firm prediction of a future moon for that planet. According to the report at UniverseToday, “The team has also confirmed a future moon of Jupiter. Comet 111P/Helin-Roman-Crockett, which has already orbited Jupiter three times between 1967 and 1985, is due to complete six laps of the giant planet between 2068 and 2086.”