You are not considering the effect of general relativity. See theoretical physicist Professor Matt Strassler's page where he gives the exact same example of ho

You are not considering the effect of general relativity. See theoretical physicist Professor Matt Strassler's page where he gives the exact same example of how energy can be stored that I did: https://profmattstrassler.com/articles-and-posts/particle-physics-basics/mass-energy-matter-etc/mass-and-energy https://profmattstrassler.com/articles-and-posts/particle-ph.... All forms of energy, including potential energy in the form of a compressed/stretched spring, couple to the gravitational field. Again, read about the stress-energy tensor for how this works. > In short, this is an absurd statement that tries to redefine a scientific definition for...I don't even know? Sensationalism? What I've said is not even remotely controversial in the physics community. Don't take my word for it; ask anyone who has taken a basic graduate course in general physics and they will agree that a compressed spring or a spinning ball weighs an imperceptibly (i.e., immeasurably) small amount more than the uncompressed spring or stationary ball, should you have a hypothetical scale that was so precise as to be able to measure the difference.