For the entertainment of Steve and others, here is one derivation. There are many ways to solve a differential equation, even one of Einstein's equations. Thanks to the encouragement of Kea and other friends, this was briefly posted 17 months ago before being taken down. As more papers are written, the writing style improves. Since this was written additional supporting data has been gathered from the Lunar Laser Ranging Experiment.
Someone is scheduled to give a talk at the APS Meeting in St. Louis USA on April 14, details in their program.