Shemamforash

OK heres one that has stumped me and my friends. As we don't know how universes form with complete certainty lets imagine that spontaneous generation of matter IS what happens. Imagine a small universe containing two tennis balls set one metre apart. They have absolutely no energy or magnetism, only a very weak gravitational field. They are completely motinless in this small universe. After so long they would eventually attract towards eachother and collide. Energy from nothing!? Obviously this is theoretical but it would illustrate a point? Thanks guys