Quote:
Originally Posted by undidly
Your understanding is too simple.
If I (the observer ) am on Earth and everyone is moving away then they will meet at a point on the opposite side of the Earth to me.
I know they are moving away because of Doppler shift,radio or light.
If I (the observer ) am on an expanding Earth then everyone is moving away
but each says everyone else is moving away.
We all know others are moving away because of Doppler shift,radio or light,
and in the same direction and maybe at the same speed as in line 3,4,5.
Each may say that the others will collide at a point on the opposite side to where they are.
We may think we can calculate when the collisions will start but by then the
distance will be great enough that ever more time is needed.
The collision point is always on the other side (from the observer) and is always too far away.
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Your understanding is too simple, as you are neglecting the
Copernican principle, even if you think you aren't. If all observers think everything is diverging, then no observer will ever see everything converging.
In your example where the Earth is expanding and that expansion causes all coordinates to become more distant from their neighbouring coordinates, then no coordinate ever gets closer to another and none will ever "collide". If it looks from this side like everything is moving towards the other side, but from the other side everything looks like it is moving towards this side, but on no side does any coordinate actually converge towards another, then there is nothing but an
apparent illusion of convergence that does not really exist.