I have a physics question that’s puzzling me. If say there was theoretical environments were there was absolutely no friction, but have a large solid celestial body that exerted significant gravity and there was an object that was perfectly elastic. If this object were dropped at say 10 meters from the surface of this celestial body, would not the object bounce exactly 10 meters, and continue to bounce forever? I asked somebody that seemingly should be very knowledgeable at this but they told me no because of gravity the object couldn’t go the same height. I don’t see how that makes any sense if it was in this theoretical situation because it is just like if a ball was rolled down a incline to a level surface then to a oppositely inclined plane, if no friction was present the ball would roll back and forth on this forever reaching the same height each time. Since energy can’t be created or destroyed why would the energy in this perfect bouncing object be lost? The only reason I see that the object would not bounce forever is because there is no way that a perfectly elastic object or friction free environment would exist. Please explain to me what is the truth and tell me detailed simple logical reasoning to it. Thanks!