If the universe has a fixed amount of mass, does it mean it has a fixed amount of energy or not? Because of the whole $E=mc^2$ thing?
2377
Is the total energy of the universe zero?
108384
Special Relativity and $E = mc^2$
149674
Kinetic energy of a photon and Schwarzschild radius
95153
Is the electromagnetic mass real?
76283
Equipartition of energy
60172
How to explain $E=mc^2$ mass defect in fission/fusion?
53455
Relativistic speed/energy relation. Is this correct?
112264
Cosmological constant doubts
112366
Is mass an observable in Quantum Mechanics?
158809
What is the status of massless photons traveling through a medium?
107902
Is Kinetic Energy stored as (rest) mass?
40148
Does light have mass?
62867
Is $E^2=(mc^2)^2+(pc)^2$ correct, or is $E=mc^2$ the correct one?
35463
How come the universe is made of matter and not antimatter?
1031
When does Hamiltonian equals to energy of the system?
50700
Could Dark Energy just be particles with negative mass?
45625
Is energy content of a system different depending on the observer?