Is the total mass of the universe constant in time?
2377
Is the total energy of the universe zero?
136281
Is the universe expanding, or is everything in it getting smaller?
22090
Does the (relativistic) mass change? Why?
112366
Is mass an observable in Quantum Mechanics?
55815
Why doesn't mass of bob affect time period?
76637
Why aren't particles constantly "measured" by the whole universe?
84892
What truly is mass, and is there a direct way to measure it?
117108
Is the Universe being dragged into a singularity rather than expanding?
57305
Relativistic Mass and Gravity
108910
Age of the universe $ \equiv 1/H$?
13080
Why is the cosmological constant a scalar?
152888
Schwarzschild Radius of the Universe
123854
Would time speed up near a large body of negative mass relative to observers in micro gravity?
152130
Maximum size of the observable universe?
79708
Is the energy density of vacuum uniform in the whole universe?
13662
Did time exist before the Big Bang and the creation of the universe?
127479
Is there any true inertial reference frame in the universe?