3 ms·
I feel like this an overly aggressive takedown of a strawman that "Lagrange points are stable equilibria", which no one makes.
by mjfl 7y ago
I feel like this an overly aggressive takedown of a strawman that "Lagrange points are stable equilibria", which no one makes.
- sandworm101 7y agoI think the article make exactly that statement. Repeatedly. And thanks to many scifi stories (gundam) there is a common belief that spacecraft or colonies will sit nicely at these points when that simply is not true. Criticism of the article is deserved. "The interaction of the forces creates a point of equilibrium where a spacecraft may be "parked" to make observations." "Because of the stability of these points, dust and asteroids tend to accumulate in these regions." "Points L4 and L5, however, are stable, "like a ball in a large bowl," according to the European Space Agency." That last one is particularly deserving of ridicule because it narrates the false belief that there is only one "parking spot", that two unguided aircraft will collide like a pair of bowling balls "in a large bowl". The chances of that occurring are akin to throwing a basketball randomly out of a plane somewhere over north america and having it score the final points in the NCAA final.
- Lukas_Skywalker 7y agoThey should be compared to a reversed bowl where any slight deviation from the center makes the balls move away exceedingly fast. But, if anyone could place the balls exactly on top, they would stay.
- DavidSJ 7y agoNo, the L1, L2, and L3 points are like that — unstable equilibria. But the L4 and L5 points are stable.
- Lukas_Skywalker 7y agoSorry, you are right. I glossed over the parent writing about L4 and L5
- gus_massa 7y agoL4 and L5 are like a large frictionless bowl. In a normal bowl with frictions the balls loose energy and eventually go to the bottom and colide. In a frictionless bowl they just keep spinning forever (until they colide by chance, if the bowl is large enough, the probability of collision is small). Also it's not a circular bowl, so IIRC the orbits are not closed and are difficult to draw.