Sun-Milky Way Lagrange 'points'

[ihwip]

I was thinking about the STEREO mission and got to wondering about how complicated the Lagrange points of the Sun would be. Would these points be less stable and subject to movement due to the changes in galactic density as the Sun moves along in its orbit? I'm talking more about L4 & L5 specifically. I am thinking that due to the vast distances and nearby stars the regions of least gravity would be far less stable than their Earth-Moon or Sun-Earth counterparts.

I don't recall reading anything anywhere even speaking of Lagrange points for the Milkyway-Sun system. Is it because the can't exist?

 

[DrRocket]

I was thinking about the STEREO mission and got to wondering about how complicated the Lagrange points of the Sun would be. Would these points be less stable and subject to movement due to the changes in galactic density as the Sun moves along in its orbit? I'm talking more about L4 & L5 specifically. I am thinking that due to the vast distances and nearby stars the regions of least gravity would be far less stable than their Earth-Moon or Sun-Earth counterparts.

I don't recall reading anything anywhere even speaking of Lagrange points for the Milkyway-Sun system. Is it because the can't exist?

Lagrange points are special solutions of the restricted three-body problem, two large bodies and a small one. The Milky Way is more than a single large body for the purposes of the problem as you have posed it.

There is no reason to believe that there are any stationary points in such a gravitational system. And if there were the problem is too hard to solve to find them We can't even solve the general three body problem. The 200 billion body problem is way too hard.

 

[vogon13]

The sun/galaxy L4 and L5 points are 30,000 light years away. Not sure what use they could ever be.


Also, as already alluded to, essentially, the sun orbits the center of mass of the Milky Way, and as a diffuse conceptualization of the necessary math, I am pretty sure these points are diluted in the extreme, and subject to confusion with the other 100,000,000,000 or so pairs of Lagrange points from all the other stars in the galaxy. Disruption of all Lagrange points by passing molecular clouds would also be extreme. The 'focusing' effect of the sun/galaxy interaction at L4 and L5 is going to be sorely taxed by myriads of competing effects.

 

[CalliArcale]

Actually, the Sun does not orbit the galactic center, at least not in the same sense that Earth orbits the Sun -- so the Sun-Milky Way lagrange points do not actually exist. As DrRocket indicated, it's not a situation that can be safely expressed as a three-body problem. (Furthermore, the Sun is too small compared to the galactic center; its mass is negligible by comparison.)

The Sun is so far away from the galactic core that the core's gravitational field is insigificant. Seriously. What the Sun's gravitationally bound to is the galaxy itself. Vast clouds of interstellar dust, billions of stars, Lord only knows how many planets and planetoids..... It's bound to the stuff of the galaxy itself, and most of that is *not* in the core. So there aren't any Sun-Galactic-Center Lagrange points. There can't be. The real system is far more complex and interesting than that.