Submitted by **_bidooflr_** t3_11isl13
in **askscience**

Just thought about it so my thoughts are a bit confused.

I know time depends on gravity force as time-space is a field. When you are next to a heavy body time is faster. When we calculated the age of the universe we used thermodynamic equations that ruled how it will expands and reversed them to find a single point, but that only applies to calculations and observations made on earth right? So is our universe 13.7 billion years old only for a constant earth gravity? Would it be anither result somewhere else in the universe? Could it be shorter as in the beginning of expansion everything was very dense and thus happened faster?

Aseyhet1_jb0odnt wroteWhen we say that the universe is 13.7 billion years old, this is actually in the rest frame of the cosmic microwave background, not that of the Earth. However, the difference due to gravitational time dilation (mostly due to the galactic potential) and kinematic time dilation (since we're moving at ~370 km/s with respect to the cosmic microwave background) is of order one part in a million, so any ambiguity in the age of the universe due to time dilation is much smaller than the measurement uncertainty in the "13.7 billion years" value.

More generally, the question of whether the age of the universe depends on where you are depends entirely on what convention you adopt. There is no such thing as a universal "now". If you wanted, you could

definethat "now" means the elapsed time, in the cosmic microwave background frame, is 13.7 billion years. This convention is called "synchronous gauge" and is commonly used in cosmology calculations. Under this convention, the age of the universe does not depend on position.For other conventions, like the "Newtonian gauge" that is also commonly used in calculations, the age of the universe does depend on position.