A common framework for explaining spacetime gravitation is the rubber sheet with a heavy ball, showing that other objects on the sheet fall towards the ball. Th

A common framework for explaining spacetime gravitation is the rubber sheet with a heavy ball, showing that other objects on the sheet fall towards the ball. This is really flawed because it explains gravity using gravity. Instead, you keep the rubber sheet and the single ball. Instead of placing other objects on the curved rubber, project (using a projector if you want) a straight line (from a flat surface) down onto the rubber. If you trace the projection of the line onto the rubber, you'll notice that it is no longer straight - it curves with the rubber (especially if you subsequently flatten the rubber out). That's a world line[1]. That's the direction of movement that an object would see as its "momentum" - but it wouldn't actually follow the world line, as the world line changes when the object moves. To build a geodesic (the actual orbit/movement of the object), you need to move along the world line and then build a new one, repeatedly. I haven't completely figured out the instructions to build a geodesic in this analogy, but seeing/imagining the curved world line should be enlightening: There is no attraction. [1]: https://en.wikipedia.org/wiki/World_line#World_lines_in_general_relativity https://en.wikipedia.org/wiki/World_line#World_lines_in_gene...