Gravity and Universal expansion

[phinds]

What I failed to say was 'undergoes a change along the line that it is traveling'.

OK, yes that would be acceleration.

... what I am questioning is that any physical body in the Universe is undergoing the reverse of such a change in all directions simultaneously.

Such a change requires that a force be applied. What force is it that you think is being applied to the Earth in all directions simultaneously, that causes it to move in all directions simultaneously ?

The "reverse of such a change" in this case just means "no change at all" and your theory does not seem to me to hold water.

EDIT: When I say the opposite of "reverse" in this case means "none" what I mean is that you cannot decelerate in all directions at once any more than you can accelerate in all directions at once so you can only be talking about no acceleration.

 

[Rob Benham]

What force is it that you think is being applied to the Earth in all directions simultaneously, that causes it to move in all directions simultaneously ?

That's a good question.

I visualize a line from a point at the centre of the Earth going through a particle at the surface, and on to a distant or fixed star*. Take this to mean a visible object not in our galaxy. I assume the surface particle is moving away from that distant object for the two separate reasons mentioned earlier. I also assume that velocity is increasing.

Now construct such a line through every particle on the surface of our planet. I can only see that it is decelerating in all directions simultaneously. What affect that might have is what I've been curious about for a very long time. *Now I remember where that term came from. It was used by us old timer airline skippers when answering papers on gyros and astral navigation. It occurs to me now that we were unaware that we were only pointing our sextants at stars within our galaxy. )

 

[phinds]

I can only see that it is decelerating in all directions simultaneously.

And I can only say again that such a concept makes no sense. You cannot accelerate (or decelerate, which is just negative acceleration) "in all directions simultaneously". Motion is relative. Acceleration is not. In the Earth's frame of reference, the Earth is not moving.