I guess I couldn't get past the conclusion that regardless of an observer's speed and direction... that he's standing still and the universe is in motion around him. If someone is standing still, it's impossible to slow down. So Einstien says if we accelerate to near light speed that time, mass density and gravity change... but then if you slow back down to Earth speed they revert to normal. My question is, "how is it possible to slow from near light speed if you were standing still?" You'd have to decelerate. A further understanding of Relativity will make this contradiction go away?
Thank you. So... I'm suggesting that the fact that we're traveling at near light speed is responsible for our mass density, and that only exists in a small window of velocity at near light speed. The 10 points I make near the end of the video support this idea.