Thanks Bernard. I still find the attractive force counter intuitive - boomerang analogies not withstanding. In GR the attractive force of gravity makes perfect sense. As you may have noticed I'm trying to go back to the start and understand the standard model from the ground up. I'm hoping that will help me understand better why people don't accept formulations of the fundamental forces that make intuitive logical sense - such as this -> [www.calphysics.org]