George and I had several lunchtime conversations during which we tried to grasp the non-intuitive aspects of Einstein's General Theory of Relativity. We got started on this topic after George had read Tom Van Flandern's book Dark Matter, Missing Planets, & New Comets.
Van Flandern points out that gravity appears to act instantaneously at a distance, and proposes a very different theory for how it works. Steve Carlip, a professor of Physics and a specialist on Genreal Relativity, has countered Van Flandern's theories a number of times, and provides explanations for why a gravitational field propagates at the speed of light, yet it's effects on objects appears to be instantaneous.
Yes, yes... but why am I dragging all this out of the dustbin now? Well, in a recent discussion thread on Tom Van Flandern's website Metaresearch.org, one of the more sensible contributors actually cited the Lunch With George gravity web page (it's the fourth post down on the page).
We've come full circle. Van Flandern's ideas got us talking, we did a lot of research, and ultimately we wound up on Van Flandern's website.