« on: 24/10/2011 11:29:57 »
I would say that if we look at a clock that "moves" away from us at speed 0.5 c, because of expansion of space, and a clock that moves away from us at speed 0.5 c, then we see the clock that "moves" is running faster than the clock that moves.I don't see. Gravitation of our galaxy does not make kinematic slowing of time of such very far galaxy.
Because: "moving" can reach speeds like 5 c, while moving is always slower than 1 c.
If we look at a galaxy that is "moving" at speed 0.9 c, and moving at zero speed, then we see no Lorentz contraction in the galaxy. Or do we see?
It is important to remember that the Lorentz contraction is a 1-dimensional thing: it applies only in the direction of motion: towards or away. It is also the case that our observation of the extent of something is a two-dimensional thing: we can observe up, down, left, right, but not towards, away. So we have no means of directly observing whether the contraction applies or not (to the component of motion directly away from us) when we look at distant galaxies. The two dimensions of observation and the one dimension of contraction are orthogonal.
I was thinking about a large mirror to help us see what the side of a receding galaxy looks like.
But now I can see that universe is transparent enough, so we can see that receding galaxies are not packed together in the towards-away dimension.