Stars have to have enough mass to have enough gravity to start and sustain a nuclear reaction that constantly blasts energy out in all directions. This limits just how energy-dense they can get. What they lack there, they make up for in size and lifespan.
We can make sustained nuclear reactions in much less space using engineered pressure instead of gravity, so that skews the energy density ratio.
We can make sustained nuclear reactions in much less space using engineered pressure instead of gravity, so that skews the energy density ratio.