Time is a variable.
1 second in our frame, might not be our concept of 1 second, in another frame.
Gravity possesses concentrated time.
Maybe
that’s a good way of looking at it. We understand that time is relative, but since space and time are different manifestations of the same thing (time is simply dimensional space that is in motion relative to us,) then space/distance is also relative. Fascinating stuff. No need to travel billions of light years when all the stars are right here with us. I hope someday soon we have the technology to reflect that. Instantaneous travel universe-wide would be a hoot.
“Gravity possesses concentrated time.”
It depends on how being “concentrated” (as a concept) affects the experience of time.
There is measurable evidence that the greater the gravitational pull (or linear acceleration) within a frame of reference, the slower time moves. It’s called “gravitational time dilation”.