Researchers call it sheer coincidence that a newly discovered piece of space junk is officially designated WT1190F. But the letters in the name, which form the acronym for an unprintable expression of bafflement, are an appropriate fit for an object that is as mysterious as it is unprecedented.
So why is "What The Fudge" unprintable?
There was a good comment on the "Three Body" oribital problem in the OP's article's comment section.
Someone asked about how something could orbit the "earth-moon system" and it was pointed out that for long orbits, the "outsider" object could be looked at as orbiting around the center of gravity of the other two bodies' masses. This is the "three-body" problem.
If you ever get a chance to read "Newton's Clock: Chaos in the Solar System" by Ivars Peterson, do so.
Besides being generally interesting, it illustrates how "chaotic" the solar system really is, because we're not looking at a three-body problem, we're looking at a "greater-than-nine" body problem... not even counting the asteroids and other minor masses.
The book indicates that there really is no such thing as a stable orbit. They're only stable in terms of a small slice of time. The "stability" of "an" orbit just depends on how refined your calculations are over what period of time, and whether you've accounted for all the bodies involved, even tiny ones.
Terry, 230RN
REF:
http://www.amazon.com/gp/product/0716727242?*Version*=1&*entries*=0#reader_0716727242