In a word, if you are sitting on the Earth, if I'm not mistaken you are experiencing Time Dilation compared to being in deep solar system space. Due to the mass of the Earth.
However. We're all sitting in a galaxy, and it weighs a lot.
(Perhaps 2e40 kg? I have no idea if issues like "dark matter" radically effect this.)
Can anyone quantify,
a) my Time Dilation sitting on Earth - versus in deeper space
b) my Time Dilation sitting in the Milky Way - versus deeper in space
We're all in the Universe. It weighs a lot.
In fact ..... are we all experiencing Time Dilation because of this being-in-the-rather-heavy-Universe affair?
c) if so, how much? Thanks.
Important ancillary question a'): I've never quite found the answer to this: we experience Time Dilation due to planet Earth. Now, if you are at the center of the Earth, you experience no gravitational pull, but, do you experience the Time Dilation??