The discussion centers on the concept of negative energy in physics, particularly in relation to gravitational potential energy (GPE) and mass. It is established that GPE is defined as negative when measured from a reference point of zero energy at an infinite distance. The Positive Energy Theorem asserts that any particle with positive mass must possess positive energy, a principle that holds true in both classical mechanics and relativity. The conversation emphasizes the arbitrary nature of energy reference points in Newtonian physics compared to the absolute nature in relativity.
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Bloodthunder said:It just depends on what your reference point is. For example, as it is convention to have gravitational potential energy at an infinite distance away to be 0 joules, our calculations show GPE to be negative.
nouveau_riche said:isn't that anything that has positive mass have positive energy?
i am not certain on that
nouveau_riche, You are absolutely correct, and this is not a trivial issue, as several responses have implied. It's true that in Newtonian physics the zero point of energy is arbitrary. You can define it to be the energy that a particle has as infinity, or you can define it to be the energy it has at the Earth's surface, as you like. But in relativity this is not the case. In relativity the zero point of energy is absolute. A particle's gravitational potential energy is negative but can never exceed its rest mass, and so the sum is always positive.isn't that anything that has positive mass have positive energy?
i am not certain on that