On Tue, Sep 3, 2019 at 11:01 PM Alan Grayson <[email protected]> wrote:
*> Just sum over the estimated total of 10^80 particles, using mc^2 by > first estimating the average mass of those particles for the rest energy, > adding their average potential gravitational energy and their average > kinetic energy. Why not? AG* > What about the energy in light, it's being redshifted by the expanding universe and thus becoming weaker, where did all that energy go? I would maintain the energy went nowhere it was just destroyed. When looked at at the scale of the entire universe why would anyone even expect energy to be conserved? Noether's Theorem says if there is time-translation invariance, that is to say if things generally look about the same from one time period to another, then matter-energy is conserved, but in our expanding accelerating universe things don't look the same. So it might be better to say that in general relativity spacetime can create energy, as it does when it accelerates the expansion of the universe, or destroy energy, as it does when it redshifts photons in a expanding universe). So energy simply isn’t conserved globally at the level of the entire cosmos, although it is locally at least approximately. John K Clark -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAJPayv2mh1Ny2t92K8gXzJtJ3HGtmEdkebZc1BaSwNP3K6SaZQ%40mail.gmail.com.
