And if we want to be really precise about where energy comes from, it’s worth noting that all elements heavier than hydrogen (i.e. all if them) are the result of stellar fusion. Up to iron in the main phase, and anything heavier in supernovae, neutron star mergers, and possibly other extremely violent events. So fission is extracting the stored energy of dead stars.
Ultimately, it’s probably all just residual energy from the Big Bang.
The energy stored in fissile elements mostly doesn’t come from fusion, it comes from gravitational potential energy released when stellar cores collapse. Most supernovae mostly aren’t fusion; almost all that energy comes from mass falling down into a neutron star or black hole.
Fissile elements are still produced through fusion, but this process takes energy from the supernova and stores it, just like fossil fuel is stored sunlight.
And if we want to be really precise about where energy comes from, it’s worth noting that all elements heavier than hydrogen (i.e. all if them) are the result of stellar fusion. Up to iron in the main phase, and anything heavier in supernovae, neutron star mergers, and possibly other extremely violent events. So fission is extracting the stored energy of dead stars.
Ultimately, it’s probably all just residual energy from the Big Bang.
The energy stored in fissile elements mostly doesn’t come from fusion, it comes from gravitational potential energy released when stellar cores collapse. Most supernovae mostly aren’t fusion; almost all that energy comes from mass falling down into a neutron star or black hole.
Fissile elements are still produced through fusion, but this process takes energy from the supernova and stores it, just like fossil fuel is stored sunlight.