"Henry Spencer" wrote in message
...
In article ,
David Woolley wrote:
...The line of action of gravitation appears to be instantaneous
between orbitting bodies, so that distance is a non-issue to the
effect.

snipsnap
There is nothing that constantly
travels back and forth between the Earth and the Sun to keep Earth in its
orbit, ...

This is an assumption.
I think the current theory postulates that 'gravitons' are constantly
exchanged, at speed of light.
This is in analogy to all other forces of nature, where some 'particle' is
associated with the force.

But hard proof either way is still is not there...we have not observed
gravitons as particles (in some quantum effect), because their energy is so
absurtly small, so we cant measure their speed directly...

--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |