Or how about the idea that all of spacetime exists, there isn't one "now" that the past and the future is another's "now", and equally real as my "Now".
From what I/we understand about time, it isn't a "constant", at least how I understand it. I do know that our perception of time is very relative.
Sort of like when you look at other galaxies through a telescope, you are quite literally looking back in time because the image you see is over 10 million years old, or more specifically you are looking at the galaxy as it was 10 million years ago. The entire galaxy could have gotten sucked up by a giant space vacuum in the last few years for all we know and can tell.