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Question on Lagrange Points

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posted on Jun, 26 2009 @ 08:37 PM
I've always known about Largrange points, but neve gave them much thought. Anyhow, a recent thought sparked in my mind while cutting grass today. When we put something into a Lagrange point, does it orbit that point? At first I thought the object would stay stationary, then thought that that is a little rediculous of an idea. So does it orbit the Lagrange point?

posted on Jun, 26 2009 @ 09:24 PM

Originally posted by Schmidt1989
, does it orbit that point? At first I thought the object would stay stationary, then thought that that is a little rediculous of an idea. So does it orbit the Lagrange point?

No. It does not orbit that point. Actually the lagrange points are points in the earth-moon and earth-sun system, where the forces of gravity equalize each other so that any spacecraft in that zone does not feel the effect of gravity and remain in "suspended state".

The Lagrangian points (pronounced /ləˈɡreɪndʒiən/; also Lagrange point, L-point, or libration point), are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects (such as a satellite with respect to the Earth and Moon). The Lagrange points mark positions where the combined gravitational pull of the two large masses provides precisely the centripetal force required to rotate with them. They are analogous to geostationary orbits in that they allow an object to be in a "fixed" position in space rather than an orbit in which its relative position changes continuously.

A more precise but technical definition is that the Lagrangian points are the stationary solutions of the circular restricted three-body problem.[1] For example, given two massive bodies in circular orbits around their common center of mass, there are five positions in space where a third body, of comparatively negligible mass, could be placed which would then maintain its position relative to the two massive bodies. As seen in a rotating reference frame with the same period as the two co-orbiting bodies, the gravitational fields of two massive bodies combined with the centrifugal force are in balance at the Lagrangian points, allowing the third body to be stationary with respect to the first two bodies.[2]


posted on Jun, 26 2009 @ 09:36 PM
In addition to peacejet's fine post, there is this:

L4 and L5

The L4 and L5 points lie at 60 degrees ahead of and behind Earth in its orbit as seen from the Sun. Unlike the other Lagrange points, L4 and L5 are resistant to gravitational perturbations. Because of this stability, objects tend to accumulate in these points, such as dust and some asteroid-type objects.

A spacecraft at L1, L2, or L3 is ‘meta-stable’, like a ball sitting on top of a hill. A little push or bump and it starts moving away. A spacecraft at one of these points has to use frequent rocket firings or other means to remain in the same place. Orbits around these points are called 'halo orbits'.

But at L4 or L5, a spacecraft is truly stable, like a ball in a bowl: when gently pushed away, it orbits the Lagrange point without drifting farther and farther, and without the need of frequent rocket firings. The Sun's pull causes any object in the L4 and L5 locations to ‘orbit’ the Lagrange point in an 89-day cycle. These positions have been studied as possible sites for artificial space stations in the distant future.

This is the link:

[edit on 6/26/0909 by weedwhacker]

posted on Jun, 26 2009 @ 09:38 PM
Wow, so it is both, depending on what Lagrange point. Whodatunkit.

Thank you, thats exactly the info I was looking for.

[edit on 6/27/2009 by Schmidt1989]

posted on Jun, 27 2009 @ 01:15 AM
reply to post by Schmidt1989
You might be interested in NGChunter's ideas about looking for artificial objects in the L4 and L5 points. Amateur SETI...A new search for artificial objects at stable Lagrangian points (amateur SETA)

posted on Jun, 27 2009 @ 01:56 AM
Lagrange points are areas of gravitational equilibrium. They are not restricted to the Earth/Sun or Earth/Moon or any other particular system. They maintain their position relative to the bodies which produce them but are not stationary in space. An object in a stable Lagrange point is not really orbiting a central mass but being sort of "pulled" along by the net gravitational force.

It is possible to "orbit" some Lagrange points. While not a true orbit in the sense of falling around a mass, "halo orbits" have been utilized by several satellites (including SOHO).

posted on Jun, 27 2009 @ 05:33 PM
L4 & L5 have the weirdest kind of stability, where the object first moves away then is brought back by the Coriolis force.

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