Ive found a lot of images of the moon identifying gmascons all over the moon due to different surface features and densities. Most of them look like this:

enter image description here

Im wondering if you could take a map like this, and a map of Earth, then create a gradient like this but for the Earth-Moon system for anything within those bounds. Obviously this would only work for an instant in time, as the Earth rotates and the moon orbits... however Ive wondered if there exists a diagram like this which includes mascons for any given point in space around the Earth moon system.

Is there any such diagram? Even a 2D approximation of such a diagram assuming the entities were coplanar and non rotating would be cool just to see a concept. The values for each point in space would be a direction and a magnitude, possibly only calculated every 100km or such.

I realize that im rambling at this point but Id be interested to know what the mame of such a diagram is provided one exists.


These kind of maps are not that common, however, when they are used they are used primarily to visualize Lagrangian Points. Maps for Lagrangian Points are normally very general and not highly detailed. Here are some images from Wikipedia visualizing the Lagrangian Points in the Earth-Sun system.

Earth sun plots

Earth sun plots

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  • $\begingroup$ Is there a specific name for this type of map, and is there one that includes gravity variations? I've seen these before on a lot of answers involving NRHO and such, but never saw them given a moniker, nor have I ever seen one varied by anything other than generic body mass. $\endgroup$ – Magic Octopus Urn Jul 3 '19 at 13:18
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    $\begingroup$ @MagicOctopusUm: Particularly those maps are called 'zero velocity curves'. Why zero velocity? They originate in the idea to plot an effective gravitational potential $\Phi_{eff} = \Phi_{grav} + \Phi_{centrifugal}$. This is a function of position only. However in the three-body problem $\Phi_{eff}$ is not conserved, instead the Jacobi-constant $C_J$ is, which is velocity dependent. Then, setting all $v=0$, $C_J$ reduces to $\Phi_{eff}$, which is the plot you see. For details: Murray/Dermott: Solar system dynamics, chap. 3.3. $\endgroup$ – AtmosphericPrisonEscape Jul 3 '19 at 13:44
  • $\begingroup$ @atmosphericprisonescape thanks! That reference is awesome. I found a 66 slide slideshow synopsis of it which stated they were also referred to as effective potential contours. I like zero velocity curves more though with your explanation :)! Thank you for the addition. $\endgroup$ – Magic Octopus Urn Jul 4 '19 at 1:14

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