(December 25, 2022 at 3:34 pm)Jehanne Wrote:(December 25, 2022 at 10:32 am)polymath257 Wrote: Once again, the problem is that energy is NOT a scalar quantity. It is one component of the four-dimensional energy-momentum vector. As such, it simply doesn't have a well-defined value at each point. Even observers moving at different speeds will measure the energy of an event as different. For a flat spacetime, this can be resolved frame-by-frame. When curvature effects are also brought in as well, you can't even make a common frame of reference at different points.
In the case of dark energy (old school, the cosmological constant), the easiest local frame to use is the co-moving frame. And, in that frame, it represents a type of energy density of the vacuum. But that doesn't allow to 'integrate over the volume' to get a meaningful answer.
Sorry. It was a good idea, but the details simply don't work that way.
Do you think that Dark Energy is a constant? If not, maybe it will reverse and become attractive??
Without a good theory of quantum gravity, we simply don't even have a good explanation for the cosmological constant at all. It's been said that the prediction for the value was 'only' off by 120 *orders of magnitude*.
In other words, nobody has any real idea.
