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PhDnotForMe

- 56

- 3

Can someone explain this equation to me? Does this mean that energy has mass in the sense that energy will create gravity? For instance, if I have a massless ball and I somehow place (3*10^8)^2 Joules or c^2 joules of electromagnetic energy inside the ball, would that ball now have a mass of 1 kg (simple algebra) and thus have a gravitational pull? Even though the ball is merely a boundary in a sense and contains no mass itself?