Hello: I am not a physicist or mathematician. I read that the universe is expanding and most pundits are 100% certain of this. The expansion seems to be much more than astral bodies moving away from each other. The actual space and fabric of the universe is expanding. Newton felt space was just space whereas Einstein felt space had substance and hence was significantly altered by the presence of mass. This alteration in the fabric of space creates gravity. The alteration in the fabric of space also curves light. As far as I know the force of gravity is more or less constant. I would think the attraction between the earth and the moon and between the Sun and the Earth is more or less the same over long periods. One question: If the force of gravity is related to the curvature of space and if space is expanding. Should there be a dilution of whatever constitutes the fabric of space and hence a gradual decline in the force of gravity?