Jupiter Caught an Extra Moon

"Gotcha! Jupiter Turned Comet into a Moon"
Space.com (September 14, 2009)

"Jupiter already has an abundance of moons, but from 1949 to 1961 it had another, temporary satellite in the form of a comet trapped in the gas giant's gravitational grip.

"Comet 147P/Kushida-Muramatsu was captured as a temporary moon of Jupiter in the mid-20th century and remained trapped in an irregular orbit for about twelve years, astronomers announced today...."

The astronomers weren't dawdling, and this isn't old news.

"...An international team led by Katsuhito Ohtsuka of the Tokyo Meteor Network modeled the trajectories of 18 'quasi-Hilda comets,' objects with the potential to go through a temporary satellite capture by Jupiter that results in them either leaving or joining the 'Hilda' group of objects in the asteroid belt. Most of the cases of temporary capture were flybys, where the comets did not complete a full orbit.

"But Kushida-Muramatsu was different: The team used recent observations tracking the comet over nine years to calculate hundreds of possible orbital paths for it over the previous century. In all scenarios, Kushida-Muramatsu completed two full revolutions of Jupiter, making it only the fifth captured orbiter to be identified...."

So What? (Remember the Dinosaurs?)

This is interesting theoretical science - but there's also a down-to-Earth application - which gets mentioned in the article in the words" "...'Fortunately for us Jupiter, as the most massive planet with the greatest gravity, sucks objects towards it more readily than other planets...'."

Whether or not an asteroid impact near the Yucatan peninsula was all it took to wipe out the dinosaurs or not, it didn't improve their odds any. So far, we've been lucky when it comes to rocks and hunks of ice falling out of the sky. The most serious recent hit we know of is the 'Tunguska Event,' back in 1908, was over a nearly uninhabited area.

If something like that went off over, say, Madrid or Perth: it would be a very bad day for people anywhere near the city; and economic problems from the destruction probably wouldn't stop at the national borders.

Not to be an alarmist, but I'm just as glad that astronomers are working to track the loose bits of debris in the Solar system. Now, if we can just get something like a space patrol set up - - - .

Related posts:

• "It Seems it Took More Than an Asteroid Hit to Finish the Dinosaurs"
  (April 29, 2009)
• "Asteroid Threat: Good News, We Have the Technology; Bad News - "
  (April 28, 2009)
• "That was Close! Near Earth Objects"
  (March 12, 2008)

Comets