>>There is no way most of the emitted energy will find its way back into a star.
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>There's a big black hole in the center of the galaxy that will probably disagree with you on that.
Oh, I don't doubt that SOME of the energy will be re-absorbed somewhere. There are black holes elsewhere, too. But the point is, most of the light energy will be lost, in the sense that it can't be converted back into useful energy.
Black holes are expected to evaporate eventually, but even if they do, it has been calculated that entropy will continue INCREASING. In other words, irreversible changes for our Universe. In any case, the evaporation of a stellar black hole - and even more for a supermassive black hole - takes so long that for all practical purposes, that mass and energy is lost to us. The time is expected to come when most matter of the Universe is converted into black holes.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
