Read on. You're right about three, wrong about two.
From the lead article:
Each planet and moon has five locations in space called Lagrange points, where one body's gravity balances another. Spacecraft can orbit at those points while burning little fuel. How much fuel does it take to travel in an orbit? I assume this is yet another example of idiotic journalism. Also, Lagrange points are not a new topic. A Google search will give you several "L5 Society" pages.
Read on. You're right about three, wrong about two. Yeah, I saw.....
So, I claim I was 60% right. (THat's what I get for going for a conclusion without ever having looked at the calculation.)
But I'll amend my comment in this way: I would think that the two stable Lagrange points are small islands of dynamic stability embedded in a larger island of dynamic instability. So, I still doubt there will be much space flotsam there....
AH, I now can claim partial vindication:
from:
http://www.wikipedia.com/wiki/Lagrangian+Point
we find:
"In practice the stability of Lagrange points is not real, as there are more than three bodies in the universe. Additional gravitational pulls from elsewhere cause objects to move away from the point. The first three Langrangian points are stable only in the plane perpendicular to the line between the two bodies. This can be seen most easily by considering the L1 point. A test mass displaced perpendicularly from the central line would feel a force pulling it back towards the equilibrium point. This is because the lateral components of the two masses' gravity would add to produce this force, whereas the components along the axis between them would balance out. On the other hand, if an object located at the L1 point drifted closer to one of the masses, the gravitational attraction it felt from that mass would be greater, and it would be pulled closer. (The pattern is very similar to that of tidal forces.)"
"However, in the particular case of the L4 and L5 points, Coriolis forces begin to act on an object moving away from the point, and bend the object's path into a stable, [kidney bean]?-shaped (from the viewpoint of the smaller mass) orbit around the point. This arrangement is stable. In the Jupiter-Sun system several thousand asteroids, collectively referred to as Trojan asteroids, are in such orbits. Other bodies can be found in the Sun-Saturn, Sun-Mars, Jupiter-Jupiter Satellite, and Saturn-Saturn Satellite systems. There are no known large bodies in the Sun-Earth system's Trojan points, but clouds of dust surrounding the L4 and L5 points were discovered in the 1950s. Clouds of dust, fainter than the notouriously difficult gegenschein,
are also present in the L4 and L5 of the Earth-Luna system."
So, in summary, even the L4 and L5 points can't be truly stable, because there are more than three bodies exerting force. Lastly, an object at L4 or L5 subjected to a pertubation assumes a "orbit" around the Lagrange point that is stable, but it is NOT forced back into the original equilibrium location.