I don't understand something here, please explain.
If I understood right, according to Newtonian Mechanics, there is absolute space, absolute time, and buncha stuff, each having coordinates of x-y-z-t. When there's rock standing still, there's really bunch of rocks that all have same x-y-z but different t. When there's rock thrown, there's actually bunch of rocks that have x-y-z that vary but are close to each other when t's are close to each other. Right?
And, if I read theory of relativity (excellent node btw, exactly what this place needs) right, Einstein's deal is the same, except that when single object "observes" world around it, its x, y, z and t-axises aren't parallel to objects' corresponding axises. Right?
Or, in other words, if you have car driving on top of train driving on ground, in Newton's system you say "ground doesn't move, train moves, car moves faster". In Einstein's system you don't say "ground doesn't move", you say "train moves relative to ground and car moves even faster relative to ground". So there isn't any static, absolute frame of reference.
So what I'm saying, you ask. Well... when you say "I want to be here 700 years earlier", in the light of above, I wonder, what does that mean? So, erosion eats ground so you'll have to adjust for that, you say. Then you say that earth rotates around the sun, so you'll have to adjust for that too, to calculate earth's location 700 years ago. Cool, I say, then proceed to ponder "But doesn't the earth-sun system move too, rotate around our galaxy? Doesn't this galaxy travel around? And is our galaxy part of some larger group that moves too? How can we ever know just what is moving, where, and how fast?". But more importantly, I ponder, "but didn't the above say that isn't any static frame to 'move' against?".
So I try to transcend the boundaries of local observer, but I can't, because any viewpoint would be "local". It would seem that there simply isn't any absolute direction of time and space. So what does "I want to go back 700 years" mean? Where do you end up? Is this motion even defined?