I recently learned that binding energy is the energy released when nucleons are fused together to form a nucleus, as the bound state of the nucleons is more stable because of the strong attractive nuclear force. I was trying to comprehend this using the analogy of gravitational potential, but it seems I'm missing something.
Suppose a ball is dropped from a height 'h' to the ground. After a couple of bounces, the ball comes to rest on the ground. The initial potential energy of the ball is lost as sound and heat in each bounce before it came to rest.
Now compare it with the potential energy of the nucleons. Since the bound state is more stable, potential energy is lost in the fusion process. In the sun, this lost potential energy is converted to radiant energy (heat and light energy). But then why do we have a mass defect? The energy is already lost as radiant energy, and on top of that, if we lose mass in the formation, that does not seem to conserve mass or energy. (The ball didn't lose mass when it hit the ground, right?).
What is that I'm missing here?