[X] My Assistant

[David]

On a non-spherical asteroid or moon (which I suppose is most of them), is the direction of "down" simply toward the overall center of gravity of the entire body, so that, for instance, on a flattened spheroid, a wheeled rover near the equator would find itself on a downward slant, and could roll "downhill" from the equator all the way to one of the poles? Or on a dumbbell-shaped asteroid (assuming the center of gravity to be halfway between the two ends of the "dumbbell"), on proceeding from the ends of the asteroid to the center, it might find itself plummeting straight down as the slope of the asteroid momentarily coincided with a line drawn through the center of gravity? Or is it more complicated than that?

[helvick]

David,

One of the problems with this is that the effect is highly dependent on the track taken. If you move parallel to the central axis of your dumbbell shaped object but remain outside the envelope described by a cylinder covering both ends then local gravity will peak when you are directly above the midpoint between the two end spheres (which is also the center of gravity of the whole system obviously).

Once you follow the surfaces of the spheres into the mid zone then the effect of reducing local gravity occurs but the same could be said of a hypothetical voyage to the centre of any spherical object.

For those with the ability to build graphical gee whiz apps there's an opportunity to make an interesting interactive educational "toy" to demonstrate these effects and allow people to play with rolling marbles down some very weird hills.