What do you mean an approximation? The formula is not that Energy is "nearly equal" to mass times the speed of light squared. Equations are a type of sentence and the phrase "is equal to" is denoted by the "=". It's not an approximation at all.

It's a notion that has been tested over and over and over again. It explains so many observed phenomena that it's just shocking. Everything from atomic bombs to the missing mass of decayed radioactive materials and a hundred things in-between. I can't imagine what you could mean by an approximation.

Probably so, at least between you and I, any way.Right.

I'm not sure where this conversation took a turn, but it seemed to me the disagreement was mostly over semantics.

Clete