Is there any meaning for this term "Total Energy of the whole universe" ?! and if yes, what is the frame of reference relative to it this should be calculated ?!

Is there any meaning for this term "Total Energy of the whole universe" ?! and if yes, what is the frame of reference relative to it this should be calculated ?!

Possibly with respect to the CMBR isotropy. I think that would be a reasonable frame or frame continuum if the Universe is finite.

There is a zero-energy universe theory: https://en.wikipedia.org/wiki/Zero-energy_universe

 

But total energy is not well-defined (or conserved) in GR: http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html

Akassem: They can only sorta guess at the total energy. Energy

=mass and they dont know the total mass. Nigel Calder says the universe has all the energy it ever has had. Big numbers though. A lot. However if the universe is all that is ,there is no frame of reference to compare it to. Sagan said the universe is defined as everything that ever is, was or ever will be. Hence by definition there is only one universe. The missing mass may be be lost car keys or sunglasses.

 

"However, there is considerable uncertainty about the mass density of all matter (visible and invisible) and energy (through Einstein's E = mc^2 equation). When one studies the movement of matter in and around galaxies, then it appears that up to about 10 times more mass is pulling at the matter (through its gravity) than is accounted for in the visible stars. This is the "missing-mass" problem. If this factor of ten holds throughout the Universe, then the total mass in the Universe would be about 6e52 kg. If the missing mass were mostly in the form of hydrogen atoms (which is not at all clear) then the number of atoms would be about 4e79." Universe, National Solar Observatory