If gravity isn’t a force, how does it accelerate objects? (Advanced) : Curious About Astronomy? Ask an Astronomer

General relativity says that energy (in the form of mass, light, and whatever other forms it comes in) tells spacetime how to bend, and the bending of spacetime tells that energy how to move. The concept of “gravity” is then that objects are falling along the bending of spacetime. The path that objects follow is called a “geodesic”. Let’s begin by looking at the bending side of things, and then we’ll come back to look at geodesics.