i thought the point of her ages was that they employed the laws of physics most elegantly. im afraid from my perspective the laws of physics are not variable, that is to say, that two plus two is always four, and likewise, the laws of gravity and motion and energy will not change. i suppose it is possible that the magnitudes could be slightly different. the gravitational constant could be slightly smaller, or slightly greater, but it all needs to balance out eventually. its very unlikely that any stable universe would looks so much like ours, and yet run on different rules.