: : : Lau: In this case, wouldn't the two spheres at the ends will be squashed (compressed)?? Since the one in the center equal forces in opposite direction which cancels each other out. so only the end spheres will be flated.

: Wayne: Looks like you are on the right track. I suspect that very little compression would occure but it would be happening along the lines you describe. Polar axis of the middle particle would stretch up and the points of contact at each edge would try to flatten.

I think the outer ones would compress and the inner would expand

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the outer would compress because of what he said, but the inner would expand because of the gravity pulling from both sides of it