答|百度派 @李建鋼lll
「http://en.wikipedia.org/wiki/Mass–energy_equivalence」In relativity, removing energy is removing mass, and for an observer in the center of mass frame, the formula m = E/c indicates how much mass is lost when energy is removed.
In a nuclear reaction, the mass of the atoms that come out is less than the mass of the atoms that go in, and the difference in mass shows up as heat and light which has the same relativistic mass as the difference (and also the same invariant mass in the center of mass frame of the system).
In this case, the E in the formula is the energy released and removed, and the mass m is how much the mass decreases. In the same way, when any sort of energy is added to an isolated system, the increase in the mass is equal to the added energy divided by c.
可以看出，在核反應中，反應物質的質量不轉化為能量。相反，反應材料質量的降低意味著反應材料失去能量。如果質量真的是一種「轉換」關係，那麼反應物質就應該提高質量。
以上內容由百度派作者提供